NATS1560
Final Exam Review: Lectures 6-11
Lecture 6.1 + 6.2: Preserving food
Learning Goals:
To define food spoilage, and identify its causes and the variables that control itTo define and the explain some pre-industrial and industrial methods of food preservation, and to review some of their history, advantages, and disadvantages
PREINDUSTRIAL: drying, smoking, salting, sugaring, pickling, cooking
INDUSTRIAL: canning, refrigeration and freezing, pasteurization, irradiation, preserving additives, vacuum packaging
methods that work by dehydration: drying, salting, smoking
Traditionally done out in the open sun or heat
Industrial drying methods: tunnel drying, drum drying, spray drying
Sugaring
Reduces moisture for microbes
Ancient greek and roman used honey and grape juice as sweeteners and preservatives
Asian countries used sugar cane as a drug spirce and luxury item
In the 1500s Portuguese and spanish traders imported sugar cane to south america and caribbean
1600s-1700s sugar industry grew with the slave trade
1800s slave labour and industrial refining made sugar a cheap mass commodity
Only after were jams, marmalades and jellies popular to preserve fruit
pickling, and how it differs from “quick pickling”
Canning
Preindustrial times cooked food was kept in sealed containers such as pie crusts and potted foods like terrines and pates sealed with fat
1810 Nicholas Appert won a french army contest with a new method of preservation (large jars with cork lids and wax)
Englishman Brian Donkin replaced jars with tin coasted iron cans which was adopted by British Navy and military
1850s industrial canning and long distance shipping became affordable for home use (includes tomatoes, peas and peaches, meat from Argentina, US and australia, fish from BC and Canadian east coast, washington, oregon, california)
Late 1800s mass produced glass cars with airtight lids made home canning of fruit and vegetables popular
Refrigeration
Pre industrial cool caves, cellars, snow and ice from mountains were used previously
1800s-early 1900s ice harvesting industry in Canada and US
1850s the heat pump and mechanical refrigeration was invented
1870s ammonia-refrigerated units and cold storage plants
1910s-1950s large electric refrigerators (Kelvinators) uses CFCs
1950s large electric refrigerators became affordable home appliances for all
Pasteurization
Named after Louis Pasteur a pioneer of microbiology
Irradiation
Test Review/Questions
What are the main causes of food spoilage?
Microbes such as bacteria, yeast and mould
Enzymatic reactions
Oxidation
What variables favour food spoilage?
Spoilage depends on moisture, temperature, acidity, and exposure to oxygen
Preservation helps control variables of spoilage and it exists in all human cultures
Industrialization increases demands for preservation methods
How do drying, salting, and sugaring slow down spoilage?
All methods include dehydration which is the removal of water to inhibit the growth of pathogens
Are usually done in the sun or heat, and cn be combined with salt and smoke (salt is hydrophilic so it speeds up the drying process, and smoke has antibacterial and antioxidant substances)
What is the difference between pickling and “quick pickling”?
Pickling is done by fermentation or curing in salt or brine, this method uses a sealed container and most of the work is done by beneficial bacteria and yeast (Leuconostoc mesenteroides and Lactobacillus plantarum or yeast) in order to develop that lactic acid and aromatic compounds
Examples are cabbages like sauerkraut and kimchi, olives, cucumbers, salami, chorizo, etc.
Quick pickling is done by direct acidification, this method soaks in vinegar solutions, and using flavouring with sugar, garlic or spices
Examples are pickles, carrots, okra, beans, mushrooms, pears, peaches, etc.
How does canning preserve food?
Uses heat and airtight container to keep food safe to eat for longer periods of time by destroying microorganisms and inactivating enzymes
What foodborne hazard can carelessly canned food present?
The risk of botulism (from bacterium Clostridium botulinum) from low acid foods (meaning pH levels >4.6) not being heated at 121*C for less than 10-20 mins
How does refrigeration slow down food spoilage?
Prevents microbial growth and enzymatic action
What global environmental issue was caused by industrial refrigeration?
The use of Chlorofluorocarbons (CFCs) for refrigerants and aerosol propellers caused the ozone layer in the stratosphere to breakdown
CFCs were used between 1930s-1987
The montreal protocol from October 16, 1987: called the international treaty for the phasing out of CFCs and other ozone-depleting substances
The ozone layer absorbs the harmful radiation especially UVB
CFC is considered a POP (persistent organic pollutant) which remain in the atmosphere forever (many many years) which can biomagnify and bioaccumulate in ecosystems with adverse effects on human and animal health
What is pasteurization?
A heat treatment used to kill microbes and deactivate enzymes while minimizing flavour changes, most applied to milk, juice, and beer
What are the different types of pasteurization?
Batch pasteurization: approx. 65*C for 30-35 mins
HTST: 75-80*C for 15 sec
UHT, 130*C for 1-3 sec
What does irradiation help to preserve food?
Exposes food t ionizing radiation (x-rays, gamma rays, electron beams) which mills microbes and pests, delays ripening and sprouting but damages DNA
The damaged food cells and proteins can cause severe losses of vitamins and alteration of texture and taste, creating harmful substances
What methods of food preservation work by dehydration?
Drying, salting, and sugaring
Lecture 6.3: Cooking
Temperature: measure of the hotness or coldness of a body (in atomic theory of matter, temperature = average kinetic energy of molecules)
Heat: energy transferred from a hot to a cold body
Heat transfer convection: by movement of fluids
Conduction: by contact, no movement of bulk matter
Radiation: by propagation of electromagnetic waves through space
Metals are good conductors of heat
Glass, ceramics and plastic are good insulators
Temperature scales:
F = 9/5 C + 32
C = 5/9 (F-32)
K = C + 273.15
Heating sources for cooking
Open fire(place), brick oven, coal stove, gas stove, electric range and oven, microwave oven, induction stove
Cookware
Earthenware, ceramic, pyrex, cast iron, stainless steel, aluminum, copper, enamel coayted iron or steel, teflon (chlorine based plastic)
Cooking methods
Roasting, grilling , broiling, baking, simmering, poaching, braising, steaming, frying, sauteing, pressure cooking, mircowaving
How cooking changes food: Changes the colour, flavour and texture of food
Blends flavour molecules
Intensifies flavour by drawing out water
Polysaccharide degradation
Starch gelatinization
Protein denaturation
Browning reactions
Caramelization (sugars at high temps)
Maillard reactions (sugars + amino acids at high temps)
Cooking and nutrition
Cooking affects the nutritional value of food
Makes more calories available to be absorbed and metabolzied
Decreased energy cost of digestion
Makes food safer and slows down spoilage by killing microbes and eactivating enzymes
Cooking can also cause
Loss of vitamins (espcially B an C since they are water based)
Fat degradation (above the smoking point)
Creating toxic compounds (acrylamide, PAHs and others)
Lecture 7.1 + 7.2: Food and Fermentation
Learning Goals:
To define fermentation and distinguish the scientific definition from the common usage of the word
Scientific definition: anaerobic metabolic process (=energy production in absence of oxygen) occurring in bacteria, yeasts, and oxygen deprived muscle cells. It helps transform organic molecules into other molecules (mostly sugars, alcoholic and proteins)
Common usage: fermentation refers to the desirable transformation of foods and drink by the beneficial action of microbes to process and preserve foods (can occur in the presence or absence of oxygen)
To define the difference between alcoholic fermentation and lactic acid fermentation
Alcoholic fermentation produces ethyl alcohol and carbon dioxide (CO2)
Used to make beer, wine and bread
Fermentation occurs on yeast and some bacteria
Lactic acid fermentation produces lactic acid
Used to make cheese, yogurt, etc
Fermentation occurs in muscle cells
Acetic fermentation: acetic acid
To describe milk as a food and as a raw ingredient, and identify the main fermented and non-fermented milk products
In human diets, cows milk si the most common, but also comes from goats, sheep, buffalo, etc.
Cow milk composition: 87% water, 5% sugar (lactose), 3.8% fat, 3.5% proteins (casein and whey), Vitamins (a and b complex), minerals (mainly calcium), enzymes, other molecules (flavour)
Unfermented milk products: creams (half and half (12% fat), table (18% fat), whipping cream (35% fat)), butter, ice cream, gelato
Fermented milk products: sour cream, cultured butter, buttermilk, yoghurt, cheese
To highlight the uses of fermentation for food processing and preservation
Fermentation has been used historically to produce a variety of fermented foods and drinks
Fermented foods and drinks have been important in part of diets in every human culture
To make foods and drinks (cheese, beer, wine, bread, etc.)
In the 19th century Louis Pasteur and other scientists discovered that fermentation and decay are results of the action of microbes on organic molecules, giving birth ro the science of microbiology
To name the most useful lactic acid bacteria
Lactic acid fermentation: lactic acid bacteria transforms lactose into lactic acid, it curdles the milk and prevents growth of harmful microorganisms, various species of lactic acid bacteria from genera Lactobacillus, Lactococcus, Streptococcus and Leuconostoc
To describe cheesemaking as an example of the use of fermentation
Lactic acid bacteria turn lactose into lactic acid which causes curdling
Rennet enzymes (chymosin) enhances the formation of curds and whey in cheese making processes
Whey can be used to make ricotta (=cooked again)
Curds are further processed in different ways which may include being strained, salted, cooked, kneaded, stretched, pressured, aged, etc
To distinguish cheese from “processed cheese”
“Cheese product” is an indicator of mass produced cheese
“Milk ingredients” and the addition of emulsifers, colours, ad other additives
These products are cheaper ad have longer shelf lives
They come pre sliced, or pre packaged
Patented by James L. Kraft in Chiago 1916, shes the found of Kraft & Bros Co. which is now Kraft & Heinz Company, a giant food corporation
Definitions
Microbes or microorganisms: bacteria, yeast, protozoa, fungi, algae, amobeas, slime molds
Fermentation: manipulation of environmental conditions to growmote the growth of beneficial microbes and inhibit the growth of harmful microbes
Curdling: addition of acid to milk makes casein molecules clump, separating curds from whey
To describe alcoholic fermentation
Alcoholic fermentation is how yeast converts sugars into ethyl alcohol and carbon dioxide
Ethyl alcohol or ethanol (“drinking alcohol”) is a psychoactive substance and narcotic
It moderate amounts it causes mild inebriation
In larger amounts intoxication and addition
It is also an antiseptic, killing harmful microbes
To define “wild yeasts”
Alcoholic fermentation is also considered a wild year or natural starters
Name the microorganisms most commonly used for alcoholic fermentation
Saccharomyces cerevisiae
To describe the most common drinks and foods produced by alcoholic fermentation, their raw ingredients, and their processing ↴
Wine
Vinification (wine making):
Grapes are crushed into must
Wild year or inoculated Saccharomyces cerevisiae convert sugars into CO2, ethanol and aromatic molecules
Skins are steeped to give colour and stronger flavours
Wine is racked to eliminate the dregs (dead yeast and skins), filtered and fined
Wine is aged, and if its in oak casks, the contact with the wood adds complexity to flavour
The finest wines are up to 30-40 years old
Wine is mostly made form grapes of Vitis vinifera, with over 1300 varieties
Some examples: cabernet sauvignon, merlot, chardonnay, riesling, etc.
Wines can alo be m,ade form other fruit like cherries, dates, apple, pears, etc.
Terroir: place of origin, giving distinctive character to each wine)
Alcohol content is ranges from 8-14% ABV
Beer
Is made from grains: barley, wheat, oats, rice and corn
Grains are turned into malt by sprouting then kilned and grounded
Amylase enzymes convert starch into sugars
Hops added to the wort for flavour
Yeast and fermentation converts sugars into CO2 + alcohol
Conditioning: refermenting, fining and centrifuging
Alcohol content ranges is 4-5% (up to 10%)
Ale: warm brewing (21-25*C), top fermentationwith Saccharomyces cerevisiae
Lager: bottom fermentation (6-8*C), cold brewing ith Saccharomyces uvarum
Bread
Flour: is milled grains
Hard wheat: high protein content (glutenin, gliadin)
Amylase breaks down some starch into sugar
dough = flour and water
Glutenin + gliadin (in water) = gluten
Kneading allows gluten to form and elastic mass
Leavening by fermentation: yeast (wild or saccharomyces cerevisiae) turns sugars into CO2 and alcohol, and gas bubbles amke dough rise
Sourdough bread uses a sgtarter with have wild yeasts and lactic acid bacteria, when making occurs the fermention stops
Surface water evaporation and mailard reactions form the crust and crumb
Unfermented bread
Flatbreads: matzo or matzah, lavash, rotis, chapatis, tortillas, other
Quick breads: leavened by CO2 producing chemical reactions without fermentation
Cakes, scones, cookies, pastries, biscuits, etc.
Chemical leaveners: baking powder, baking soda, ammonia salts
Test Review/Questions
What are the 3 main kinds of fermentation
Alcoholic, acetic, lactic acid
How does the common usage of the term fermentation differ from the scientific definition?
The common usage of the term refers to the desirable transformation of foods and drinks by the beneficial action of microbes, whereas the scientific definition refers to anaerobic metabolic processes only
What are the two main nutrients by weight in milk?
Water and carbohydrate: nutrients, not macronutrients, what is a nutrient and its needed in macro quantities but behaves more like micronutrients in that we dont get calories from it
Are curdling and fermentation the same process?
No, curdling itself is the denaturation of milk proteins (casein) to make them clump together. Even though lactic acid bacteria occurs in fermentation curdling can also occur without fermentation
Is cheese an unprocessed food?
No, it is processed from milk
What is the most used miroorganism or alcoholic fermentation?
Saccharomyces cerevisiae
What contributes to the distinctive character of a wine?
Terroir, steeping grape skins, and aging in casks (oak)
How is lager different from ale?
Bottom vs top fermentation, cold vs warm brewing, saccharomyces uvarum vs saccharomyces cerevisiae
What is the difference between sourdough bread and non sourdough bread?
Sourdough uses a starter containing “wild yeasts” (yeasts and lactic acid bacteria)
What happens when milk curdles and how does it apply to cheese?
Lactic acid bacteria turn lactose into laxctic acid
Lactic acid curdles milk to prevent the growth of harmful microorganisms
This curdling creates the separation of curds and whey contributing to the process of cheesemaking
How does mould affect cheese?
Mould grows on cheese which helps its flavour for aged cheese
wheels like gouda have wax, or others have a dehydrated outer shell called a rind which is maintained that allows one type of edible mold to grow on it, for cheeses like brie salt water is used to regularly clean it
Once maintenance stops and the cheese is cut all types of cheeses can become mouldy from its environment
Give three examples of each of the two main kinds of fermentation
Lactic acid fermentation
Sour cream, cheese, yoghourt
Alcoholic fermentation
Wine, sourdough, beer
What is malt and how is it used in brewing beer
Malt is a type of grain that's used for brewing beer, it provides the sugar needed for fermentation
What are the main differences between winemaking and beer brewing?
Grapes and other types of fruits are the base and are used to feed the yeast in the wine
Beer brewing relies on grains on the base and fr fermentation
Lecture 8: Where food comes from
Learning Goals:
To define arable land and fertility, and identify the main components of soil and the factors that determine soil fertility
Arable land: land fit for agriculture
Only about 5% of canadian land is arable and The urban sprawl in southern ontario subtracts prime arable land from agriculture
Land fertility is the capacity to sustain planet growth and depends on soil. Water and climate
Soil has a complex structure and varies place to place: 45% mineral component, 5% organic component, 35% water, 25% air. Soil comes from rock weathering (breaking down into fragments and particles over centuries) and biological activity
Agriculture and other human activities cause loss of land fertility through soil erosion, compaction, salinization, etc.
Soil degradation is used by unsustainable land use and management practices, as well as anthropogenic climate changes
33%of land today is moderate-highly degraded due to erosion, salinization, compaction, acidfcation and chemical pollution
Soil is considered a nonrenewable resource because it can't recover within a human lifespan, and the current rate of soil degradation is unsustainable
Growing crops exhausts the fertility of the land and deplates the soil of planet nutrients, farmer used to restore fertility with aminal manure and green manure
They also did crop rotation
Twpo fiel rotation: alternating ctop growing and idling (fallow field)
Three fiel rotations: alternating grains, legumes and idling
To identify the main parts of the hydrologic cycle
The natural cycle of precipitation, runoff, and evaporation
Only about 2.5% of the earth water is fresh and 3.4 of it is locked in ice
Earth's freshwater supply is in principle sufficient to sustain the worlds population
Unsustainable water management: wasteful irrigation, pollution, deforestation, climate chnage
2 billion people are affected by water scarcity
¼ people will suffer from water shortages by 2050
To outline and discuss the historical process of industrialization of agriculture
Within the last two centuries agriculture has become increasingly industrialised from machinery, fertilisers, pesticides, fossil fuels, monocultures and factory farming
Plant breeding for high yield monocultures, mechanisation, chemical pesticides, and fertilisers, invasive irrigation and farm consolidation and expansion of agribusiness
Industrialization has increased the productivity of agriculture but also entails great environmental, social, and nutritional costs
To discuss the mechanisation of agriculture and its effects
The first ploughs were just sticks used to prepare the soil for sowing
Heavy ploughs and wheeled plough pulled by oxen and horses expanded arable land in regions across the globe
During the industrial age the first steam and gas engines replaced animal labour
Today diesel tractors can pull multiple steel ploughs
Excessive tilling (ploughing and harrowing) causes soil erosion and water runoff
Grain harvesting and threshing used to be really labour intensive but today farmers use harvesters and combines. The use of fossil fuels, combined with capitalization created displaced workers
To discuss two main aspects of the chemical revolution in agriculture, the synthesis of ammonia and synthetic fertilisers
The Chemical Revolution- Synthetic fertilizer: Justus Von Liebig (1803-1873): a founder of organic chemistry, planet and animal physiology
Hr produced the first synthetic fertilizer popuarlized by the NPK model
Nitrogen (N)
Phosphorous (P)
Potassium (K)
The synthesis of ammonia- The Haber-Bosh process
Nitrogen based fertilizer was industrially produced due to the german chemists fritz haber and carl bosh in 1908-1913
Ammonia synthesis from its elements nitrogen front he atmosphere, and hydrogen from water and other sources
About half of the world is fed due to this process
Synthetic ferilizers cause nitrogen and ohosphprs runoff and eutrophication, loss of biodiversity, and large fossil fuel consumption
Ammonia is also used for mass production of explosives
The chemical revolution- pesticides
Crop selection and monoculture
People can gone from farming for subsistence to agribusiness and from mixed farms to monocultures only selecting high yield cash crops
In canada this looks like maize, soybeans, wheat and canola
Factory farming: intensive livestock production (of cattle, pigs, poultry, fish for meat, fish, milks and eggs)
This is done to maximize their “production” at the cost of the animals welfare and ecosystems
These farms are typically confined, overcrowded, and other forms of animals abuse occur
They use growth hormones, preemptive antibiotics
These farms produce noxious smells, waste, and greenhouse gases
Industrial farming
Mechanization + seeds that are selected or hybrid seeds + irrigation and synthetic fertilizers + use of pesticides = high yield monocultures
The number of farms has decreased while the farm sales has increased
The number of pigs has increased by x10, cows by x5 and the amount of crops by x14 in the last 150 years
Horizontal and vertical integration
Oligopoly (horizontal integration/vertical integration)
Discuss the hidden environment, social, and nutritional costs of industrial agriculture
Industrial agriculture enhances the quantity at the expense of quality, soil depletion, use of artificial fertilizers and a smaller number of high yield varieties
The price of industrial farming
There's a high input of technology, and fossil fuels
Oligopoly (horizontal/vertical integration
Labour issues and social impact
Loss of biodiversity
Pollution
Decline of nutritional values
Test Review/Questions
Definitions
Sustainability: the ability to satisfy our present needs without compromising the ability of future generations to satisfy their needs. Is a holistic idea that united environmental sustainability, economic sustainability and social sustainability.\
particle size: sand, silt, clay
smaller particles = lower permeability
Loam: sand, silt, clay, and organic matter mixture in optimal proportions for fertility
Organic layer: litter, humus, worms, insects, and millions microorganisms
What is sustainability
The ability to satisfy present needs without compromising the ability of future generations to satisfy their needs, the ability to satisfy future needs without compromising the ability of present generations to satisfy their needs
What is soil composed of?
45% mineral component, 5% organic component, 25% water, 25% air
What are the two processes through which soil is formed?
Rock weathering and biological activity?
Current and sue and management practices are
Jeopardising the ability of future generation to satisfy their needs
What is the “chemical revolution” in agriculture?
The first part of the chemical revolution is the first production of synthetic fertiliser with the NPK model, nitrogen, phosphorus and potassium
The second part of the chemical revolution is the introduction to pesticides
Insecticides
Plant extracts: pyrethrum, rotenon, nicotine, sulphate
Synthetic compounds: organochlorine compounds DDT, organophosphates, carbamates
New nicotine- like insecticides aka neonicotinoids
Fungicides
Herbicides
2, 4-D
Atrazine
Glyphosate (round up)
Rodenticides
Who was Justus von Liebig and what role did he play in the development of agriculture ?
Justin von liebig is the founder or organic chemistry and pant and animal physiology
What is the Haber-Bosch process, and what role does it play in modern agriculture?
The use of nitrogen based fertilizers beginning the industrial productivity of agriculture in the 20th century. They found The synthesis of ammonia from its elements, getting nitrogen form the atmosphere and hydrogen from water and other sources
The nitrogen cycle
A repeating cycle that moves nitrogen between living and non living things
It begins with the atmosphere, 78% of the atmosphere in volume is nitrogen gas (N2)
Since plants cant absorb or use nitrogen from the air, nitrogen fixation occurs
Nitrogen fixation: the conversion of atmospheric nitrogen (N2) into nitrogen compounds that plants CAN absorb and use
Soil and root organisms have natural nitrogen cycles from decomposing microbes in soil, the bacteria that fixes nitrogen in roots and soil
E.g Rhizobium bacteria in legume roots
The phosphorus cycle
The phosphorus cycle is the movement of phosphorus through the biosphere, hydrosphere and geosphere.
Some key steps in the phosphorus cycle:
Weathering and rain: Rocks release phosphate ions and other minerals.
Plants: Plants absorb inorganic phosphate from the soil.
Animals: Animals absorb phosphates by eating plants or plant-eating animals.
Decomposition: When organisms die and decay, phosphates are released back into the environment
What are the main kinds of pesticides?
Insecticides, fungicides, herbicidses, rodenticides
What type of pesticide is DDT
Insecticide
What was the problem with DDT, according to the book silent spring?
Bioaccumulation in song bird
What is an oligopoly
A market system in which there are a small number of producers or sellers
How does an oligopoly form?
By a horizontal integration of industries and a vertical integration of industries
What is horizontal integration
When a company buys, merges with, or drives out of the market competitors to get control
What is vertical integration
When a single company acquires control of several segments of s supply chain
What is the overall result of industrial agriculture?
A high yield in a small number of crops
Lecture 9: Industrialization of food
Learning Goals:
To explain the function of food processing in human food systems, and of the role of the food processing industry in the economy and public health today
Over the last 200 years the food processing industry has hugely grown and is now a major driver in the economy and shapes the food system
Food supply chain: sequence of steps involved in producing, processing, and moving foodstuff, through which raw materials are transformed into a final product ready to be delivered to consumers
Agri-food inputs → primary production → food manufacturing → distribution ↴
Food retailing → domestic food ↘
Food catering → eating out → outputs
Food system: is the interconnectedness set of factors, forces, ad relations that together determine what and how a human population eats
“The food syste, includes the related resources, the inputs, production, transport, processing and manufacturing industries, retailing, and consumption of food as well as its impacts on environment, health and society”
To highlight the inadequacy of the distinction between “natural” and “processed” foods and replace it with more useful distinctions between degrees and types of processing
Limiting highly processed foods is always the best decision
Every food originates from nature so therefore it is natural but all foods are processed in some way
The word “natural” is used in marketing and there is no hard line distinction between natural and processed foods but there are different degrees and types of processing
Canadian label regulations allow foods to be labelled as natural if it hasnt undergone processes that significantly alter their original, physical/chemical/biological state
Little to no processing: freshly picked fruits and vegetables, raw milk, freshly cut meat and fish, etc.
Some processing: washed, packaged, artificially ripened, pre-cut fruits and vegetables, homogenized and pasteurized milk and cream, filtered fruit juices, frozen and canned foods, etc.
More processing: sausages, patties, cured meats, smoked fish, cheese, yogurt, sour cream, etc.
Highly processed (several stages, many ingredients and additives), baked goods, crackers, candies, boxed cereal, processed cheese, soda, sauces, etc.
To define industrial food and contrast it to artisanal food
Industrial food is mass produced foods made by using industrial methods
Industrial food processing is optimized for mass production, efficiency, uniformity, and meant to minimise raw material and cut labour costs
Thi is done to raise the profit margins for manufacturers and lowering store prices
Industrial machinery and chemical substances are used
There are many hidden costs such as fossil fuel energy per kcal of food 10:1 ratio, waste/pollution/environmental damage, health issues, deskilling and loss of knowledge of workers and consumers
Added value is created by industrial processing through preservation, convenience, novelty, and consumer appeal through the engineering of cravings and advertising
Very small shares of store protfits go to farmers
Eggs and milk about 60%, bread <6% and cereal, 1%
Artisanal foods are made by hand or craft methods
To define the types and functions of food additives in industrial foods, and identify some common examples
Health canada's definition of a food additive is: any chemical substance that is added to food during preparation or storage and either becomes a part of the food or effects its characteristics for the purpose of achieving a particular technical effect
Food additives include:
Preservatives
Chemicals that prevent spoilage aka antimicrobial and antifungal agents, antioxidants which are used to lengthen the shelf life of commercial foods
E.g. sodium nitrate and sodium sitrite, sulphites, sulphur dioxide, sorbic acid and salts, sodium sorbate, potassium sorbate, calcium sorbate, BHA, BHT, ascorbic acid, citric acid, disodium EDTA
Emulsifiers, thickeners, stabilizers
Non sugar sweeteners
Classified as food additives by canadian food and drug regulations e.g. saccharin, sorbitol, aspartame, cyclamate, acesulfamek
Colours
Anti foaming agents, anti caking agent and anti sticking agents
Glazing and polishing agents
Others
Flavour enhancers
“Natural flavours”: compounds extracted from plants, animals, yeast or algae that imitate certain food flavours e.g monosodium glutamate (MSG), hydrolyzed vegetable proteins, yeast extract castoreum, castoreum, etc.
“Synthetic flavours”/””artificial flavours”: synthetic compounds from non edible sources that imitate natural flavours e.g vanillin, diacetyl and acetoin (butter like flavour)
Colours
Plant extracts: annatoo, turmeric, synthetic dyes (coal tar derivatives): yellow tartrazine, organge B, citrus red 2, etc.
Emulsifiers
Lecithin (phospholipid_
Mono and diglycerides, DATEM (diacetyl tartaric acid ester of mono and diglycerides), PGEs (polyglycerol esters of fatty acids)
Thickeners
Agar agar, carrageenan
Pectin, gelatin, gums
Food additives do not include:
Food ingredients such as salt, sugar, starch
Vitamins, minerals, amino acids
Spices, seasoning, flavouring preparations
Agricultural chemicals
Veterinary drugs
Food packaging materials
To define food fortification and enrichment, and identify some common examples
Fortification: the addition of micronutrients or fibre to commercial foods
E.g. calcium added to orange juice
Enrichment: fortification aimed to restore micronutrients that were lost during processing
Milk and milk products adding vitamin D
Some foods must be fortified or enriched as public health in intervention to prevent nutritional deficiencies, but for other foods manufacturers will voluntarily fortify or enrich food fas a marketing strategy
To discuss the problem of added sugars in industrial foods
The addition of flavour and sugar (quinine and tonic water) contributed to the development of soda
American soda fountains mix water, syrup, sugar and carbonation to make drinks
Many popular drinks like cola came was made from cocaine, and kola seeds, and fruit drinks are actually less than 25% fruit juice
Sugar comes in many many forms and added to 74% of foods and drinks
e/g malt sugar, molasses, dextrose
High fructose corn syrups or HFCS is called glucose-fructose or glucose-fructose sugar on canadian labels
Thi is made by processing corn starch with enzymes and its much sweet an cheaper than other sugars
WHO recommended reducing sugar to below 5% or roughly 25 grams or 6 teaspoons per day would provide additional health benefits
To define horizontal and vertical integration in the food industry
1850-1890 Christie, Brown & Co, Toronto become the largest cookie manufacturer in canada
1928, US National Nuiscuit Company (Nabisco) buys christie Brown & Co
2011 Nabisco merges with Kraft international
2015 Kraft merges with Heinz to form Kraft Heinz
To describe the extent, character, benefits and costs of the global industrialized food system
The food processing industry that chemically, mechanically or physica;l;y transforms materials and substances into new products, the food processing industry is aslo the second largest manufacturing industry in canada, and the largest manufacturing employer
Since 1950s large scale integration, domestically and internationally, has led to a worldwide oligopoly
Food sales and distribution has significantly changed
Local and seasonal production to global sales
From specialist retailers (butchers, bakers, greengrocers, fishmonger, confectioners) to supermarkets and superstore
Selling mindless consumption, glut, speed, and convenience of packaged foods, prepared foods, conveniences foods and fast foods
They use sly and manipulative marketing, overpackaging and non biodegradable packaging
Excessive and avoidable food waste
Economic development has been prioritized over quality, for quantity, disregarding impacts on human health and environmental destruction such as:
Deforestation and destroying ecosystems
Loss of biodiversity
Loss of fertile soil
Water and air pollution
Climate change
Sustainability is the ability to meet the needs of the present without compromising the ability of future generations to meet their needs
The current food system is unsustainable
Canada's new food guide
Issues by health canada in january 2019
The series started in 1942
Educational tool based on the best scientific evidence
Translates nutritional science into pratical advice for canadians
Nova food classification system
unprocessed/minimally processed foods (fresh/whole foods): comes from plants and animals by cleaning, cutting, crushing milling, drying, freezing without using industrial methods or adding new substances
Processed culinary ingredients: extracted and refined by industry from raw materials, to be used in food preparation/cooking to make nourishing and enjoyable dishes
Processed foods: mae by adding culinary ingredients to minimally processed foods to enhance the palatability
Ultra processed foods: products that are made to be profitable, durable, ready to eat and hyper palatable, formulated of industrial ingredients, and other food substances/additives. Branded very assertively, packaged attractively, and marketed intensely
Water and soft drinks
On distilled water contains traces of minerals
Bottled water is not purer, safer or healthier than tap water
carbonation : the addition of carbon dioxide gas
It was ivnented by Joseph Priestley in 1772 to simulate fizzy spa waters and was commercialized by Jacob Schweppe in 1800s
Test Review/Questions
What is a market in which there is only a small number of sellers?
Oligopoly
The present global food system is:
An oligopoly
How does an oligopoly form
Horizontal integration, vertical integration, diversification
The business strategy by which a company grows its operations at the same level of the supply chain is called
Horizontal integration
A food is either natural or processed it can't be both (T or F question)
False
Most foods are processed in some way and to some degree (T or F question)
True
According to Health Canada, which of the following is a food additive?
Pectin
According to Health Canada, which of the following is a food additive?
Aspartame
How does enrichment differ from fortification?
Enrichment is a type of fortification that aims to restore micronutrients lost during processing
What is an example of fortification?
Calcium added to orange juice
What percentage of the maximum daily intake of free sugars conditionally recommended by WHO is approximately contained in one can of coco cola
150%
Why did Joseph Priestley invent carbonated water?
To reproduce the healthy virtues of natural fizzy waters
What has not been a feature of the industrialization of the food system in the last 100 years?
An increase in the number and variety of specialist food retailers
Which of the following statements is correct?
About 33% of the food produced globally gets lost or wasted
What are the main categories of food additives?
Preservatives
Emulsifiers, thickeners, stabilizers
Mon sugar sweeteners
Colours
Anti foaming, anti caking, and anti sticking agents
Glazing and polishing agents
Others
What are some specific examples of food additives in each category?
Preservatives: sodium nitrite and sodium nitrate
Emulsifiers: lecithin (phospholipid)
Thickeners: agar agar, gelatin, pectin
stabilizers:
Non sugar sweeteners: aspartame, saccharin, sorbital
Colours: synthetic dyes like orange B
Anti foaming, anti caking, and anti sticking agents
Glazing and polishing agents
Others
What is the difference between natural and artificial flavours?
Natural flavours: compounds extracted from plants, animals, yeast or algae that imitate certain food flavours
E.g. MSG, hydrolyzed vegetable proteins, yeast extract
FDA: natural flavours cn refer to anything that comes form a spice, fruit, fruit juice, vegetable, vegetable juice, edible yeast, herb, bark, bud, root, leaf, meat, seafood, poultry, eggs, dairy products or anything fermented from those foods
Synthetic flavours/artificial flavours: synthetic compounds from non edible sources that imitate natural flavours
E.g. vanillin, diacetyl and acetoin (butter flavours)
FDA: artificial falvours come from petroleum and other inedible sources
What is an example of natural flavour?
MSG
What is an example of artificial flavour?
vanillin
Lecture 10
Learning Goals:
To define plant and animal breeding, species, breeds, hybrids, straight breeding and cross breeding
Plant breeding: the process of developing new varieties by seelctivng desirable traits
Animal breeding: the process of selectively mating for offspring with desirable genes
Species: a category of organisms that normally breed with one another
Species from different genus can sometimes mate but different genera very rarely
Breed: a group of plants or animals with common linage within a species, especially one developed by artificial selection and maintained by controlled propagation
Other terms for breed: subspecies, cultivar (plants), strain, variety, population, race
Hybrid: of mixed origins, crossbred or produced by mating 2 different species of the same genus
E.g. zorse
(animal) Straight breeding: mating individuals of the same breed
To achieve uniformity of characteristics
There's an issue of inbreeding depression: reduction of health, fertility, and longevity
(animal) Crossbreeding: mating individuals of different breeds
To achieve complementary characteristics
To produce heterosis or hybrid vigour: increasing size, health, ferility and longevity
Can also be damaging to health of offspring
purebred: produced by the controlled mating of an unmixed breed over many generations
E.g. purebred arabian horse
Intraspecific hybrid: within species
Interspecific hybrid: outside of species
To review a few examples of the uses of plant and animal breeding in the history of agriculture
Animal breeding: Post WII reproductive technology advanced
From the 1950s, artificial insemination was increasing in breeding efficiency
From the 1980s embryo transfer and in vitro fertilization
Plant breeding:
Practiced since agriculture existed
Selection of cultivars with wanted characters
Hybridization: cross pollination and grafting
1865, Gregor Mendel did experiments on hybridization
He found that the inheritance of a hybrid trait is determined by a pair of elements with each element coming from one of the parents and each element has two variations, one dominant and one recessive
In midterm terms Mendels elements are called genes and their other variations are alleles
To introduce the basics of classical genetics
About 14000-12000 years ago (some people say 20000 years ago) humans began to domesticate plants and animals for agriculture and other purposes
Today's domesticated varieties are distant descendant of wild species which were modified for human purposes by selective breeding and usually it was because they were unable to survive without human support
Genetics: the experimental study of biological inheritance to better understand and control breeding
The key idea of early genetics: specific characters are transmitted from parents to offspring as individual, independent units
Gene: a unit of heredity
Genotype: set of genes related to a given character, or the full set of genes of an individual
Phenotype: actual outward character or set of characters of an individual
From the 1900s-1930s
The carriers of genes are the chromosomes, microscopic structures that appear in the cell nucleus during cell division
Genetic mutations are biochemical changes in the chromosomes
Classical genetics was birthed and grew due to the support in:
Selective breeding plants and animals to improve agriculture
Interest in “good breeding” in human populations to “improve” society
Eugenics
Classical genetics are used by plant breeders and agronomists to enganc e traditional breeding methods
In the 1940s rust resistant Marquis wheat was cultivated
Canola in 1978
CAN(adian) O(il) L(ow) A(cid)
To discuss the green revolution and its connections to plant breeding, genetics, and industrial agriculture
Agricultural reforms in developing countries in 1950-1960s aimed to implement industrial agriculture techniques and increase agricultural production
The green revolution was promoted, organized and funded by american foundations and international agencies in collaboration with local governments
Mexico, india, pakistan, bangladesh, philippines, indonesia have all had a green revolution
This term was coined by the US AID Willian Gaud in 1968 to contrast it to “Red” revolutions and “white” revolution of Iran
This is a geopolitical project used to contrast ideas of communism
It was led by norman E. Borlaug and other agronomists
Higher productivity of few selected varietiies of cereal grains (wheat, maize, rice, and other crops like beans cassava and cotton
There was a high technological input and other issues while attending industrial agriculture
And this was a mixed legacy
Selective breeding/artificial selection: controlled reproduction to select desirable characteristics
Classification
Kinky People Come Over For Good Sex
To introduce the transition from classical genetics to molecular biology, and the identification of strands of DNA with the genes
1940s, molecular biology
Chromosomes are made of DNA and proteins
Genes are segments of DNA responsible for the synthesis of specific proteins
1953, the discovery of the structure of the DNA double helix
DNA molecular structure is the same for all living organism
Different species are distinguished by the specific sequence of genes in their DNA (genome)
To introduce the basics of the double-helix structure of DNA and its relation to the genetic code
DNA structure
DNA is composed of two antiparallel strands of nucleotides which looks like a ladder
A double helix is the two ladders of nucleotides twisted into a double helix
A nucleotide: a phosphate group, a five carbon sugar and one of four types of nitrogen bases
Complementary base pairs: Adenine (A) and thymine (T), and guanine (G) and cytosine (C)
The sequence of bases is the “genetic code” and template sued by the cell to construct all the proteins specific the organism
Central dogma of molecular biology: DNA makes RNA, RNA makes proteins
The knowledge of DNA structure made genetic engineering possible
To define genetic engineering, genetically modified organisms, and the main kinds of genetic engineering: cloning, gene transfer, and gene editing
Genetic engineering: direct manipulation of DNA to transfer genes from one organisms to another or modify the genome of an organism
GMO: a genetically engineered or genetically modified organism
Types of genetic engineering:
Cloning: transfer of the entire nuclear DNA of a donor organism into an emptied out egg cell of the same species to produce a genetic copy of the donor
Gene transfer (gene splicing or recombinant DNA technology): transfer of a specific gen from the DNA of a donor organisms to the DNA of a target to reproduce single genetic traits independently of the species of donor and target
A wanted gene is identified in the DNA of a donor organism
The gene is cut out by restricting the enzyme and its implanted in the DNA of another organism to produce recombinant DNA or rDNA and transgenic organism
A plasmid or virus is used as a vector, electro or chemical poration, microinjection, or gene gun to genetically engineer transgenic varieties of bacteria, planets or animals
Early successful gene transfer: human genes were transplanted into bacteria to make them produce insulin and human growth hormone rHGH
Gene editing: modification of one or more genes in an organism
To review the state of animal cloning and it use for food
The first cloned animal was Dolly the Sheep by Ian WIlmut and his team in scotland 1996
Cloning is possible for many animal species from mice cats gods goats pigs horses cattle etc
Cloning factories in china an the USA are small scale
There are many ethical cocnerns with cloning and the welfare of cloned animals
2007: FDA approved of marketing food products from cloned animals without labelling since the biotech industry claimed it was of “substantial equivalence”
Sept 2015: the EU banned cloning farm animals
In canada food from cloned animals is subject to novel food regulations and must be approved for sale
No food products from cloned animals are currently approved for sale in canada
To identify and discuss a few examples of GMO foods
GE is applied to make new designer plants and animals
Gene transfer from a donor e.g. a bacterium to target plant or animal
Silencing or editing one or more genes in the target organisms
e.g. roundup-ready crops (soy, corn, cotton), bt crops (corn, rice, soy, cotton), AquAdvantage salmon, Arctic apples
To discuss why GMOs are controversial and review the main points of the arguments in favour and against the genetic engineering of foods
GMOs are controversial due to the misinformation and fear mongering of ignorant publics, concerns cover a mix of environmental, health, amongst other issues
FOR GMOs
GE is not qualitatively different from traditional breeding methods
Just more controlled, accurate and efficient in comparison to traditional breeding
More environmentally friendly than conventional agriculture
Patenting of GE organisms is needed to protect intellectual property and foster innovation
The public is ignorant and misinformed and reacts emotioanlly out of unjustified fears
AGAINST GMOs
GE is qualitatively different from traditional breeding methods
Gene interactions and expression of genes in different cellular contexts are still poorly understood
High input GE crops, genetic contamination of wildlife, reduction of biodiversity, superweeds, superbugs
Patenting restricts access to seeds and to information and is one more cause of socio-economic inequalities
Lack of transparency and pub;ci scrutiny is undmocratic
Test Review/Questions
When did farmers begin to use selective breeding or artificial selection?
About 14,000-12,000 years ago
What is the difference between species and breed?
Breed is a sub classification of species
What is an example pf an intraspecific hybrid?
A labradoodle
What is an example of an interspecific hybrid?
A “liger”
What did Gregor Mendel aim to study with his experiments on pea plants?
The general laws of biological heredity
When gregor mendel hybridized two purebred strains of peaplants what did he find in the first generation of hybrids (F1)?
All the F1 hybrids displayed the character of one parent
What did mendel find in the second generation of hybrids (F2)?
75% of the F1 hybrids displayed the character of one parent, 25% the character of the other parent
What did mendel conclude from his experiments about the mechanism of plant hybridization?
Hereditary character that exist in two vafiations are carried by pairs of “elements” (alleles), in purebred individuals, all the inheritable elements are equal, the inheritable elements of each parent are transitted separately to the offspring, and pair up randomly with elements from the other parent
What is the key idea of classical genetics?
Hereditary traits are transmitted from parents to offspring as individual, independent units
What is an example of agricultural application of classical genetics in Canada
Marquis wheat, rust-resistant Marquis wheat, canola
From the point of view of genetics, what distinguishes an organism from another
DNA distinguishes one organism from another
What is the genetic code of an organism and how is it related to DNA
The genetic code is written in the DNA, it is a sequence of bases in the DNA, it is unique to the organisms DNA
What is the difference between gene transfer and cloning?
Cloning is a genetic copy of the donor, gene transfer selects a single gene to add
What is a transgenic organism, and how is it different from a hybrid?
A transgenic organism has a single gene transferred via recombinant DNA, a hybrid is a combination of two species
What is an early example of gene splicing?
Insulin
Lecture 11
Learning Goals:
To identify the main institutions in charge of food governance in our society
Politics dhap[es the food choices of individuals in numerous ways
Land property and labour legislation
Agricultural policy: tax breaks, subsidies, price controls
Infrastructure: irrigation, transports, power
Trade policy: domestic and import/export
Food and public health policy
Food safety regulations and enforcement
Food security policy, national and global
Scientific research and technological innovation
Environmental policy
Food production and processing is one of the main sectors of the economy
Food security, food safety, and nutrition are also public health matters
To discuss aspects of food trade and the globalization of food
Each country aims to assist its farmers and food manufacturers by promoting the export of their products while protecting them from competition by limiitng the import of good abroad
Trade barriers: tariffs, import bans and quotas, subsidies and assistance policies
Protectionist policies have been applied by all industrial countries to foster their own growing industry and become global economic powers
Since WWII industrial countries launched a concerted effort to increase international trade by removing trade barriers: international free trade
Until 1955, agriculture and food industry were largely exempted, and the food supply was regarded as a matter of national security
1947: general agreement on tariff and trade (GATT) for 20 countries
1995: world trade organization, was present 164 countries
Food is a business as any other and theres need for international food safety standards
Free trade zones
1993: EU, 27 countries with 500 million people and worth 30% of the world economy
1992: North american free trade agreement (NAFTA), USA, Canada, Mexico, with almost 500 million people
New free trade zones:
canada-United States-Mexico agreement (CUSMA) or “New Nafta” in Nov 2018
Comprehensive economic and trade agreement (CETA), canada-EU signed in 2013
trans -pacific partnership (TPP),m 12 pacific-rim countries signed in 2016, now CPTTP
Transatlantic trade and investment
To explain why food is a public health issue: food security and food safety
Food security:
The right to be free from hunger is food security
Around 1/9 people face food insecurity thats about 821 million people, with the highest number in africa with a 1/5 prevalence
Hung3r is on the rise in western asia and the root causes are povertyk, war and climate change
In canada 8.7% of households were food insecure between 2017-2018, this was 22% for single parents with children and 36.7% in nunavut
Food safety and prevention of food borne illness
1985: canada food and drug act
Illegal to sell tainted food, mislabel and adulterate it, stoere it in unsanitary ocnditions
Regulations for importantna d export of food
1997: canadian food inspection agency (CFIA)
1998, canadian food inspection system
Producers have a primart responsibility for quality
Consumers have right to know what they are buying
CFIA responisbuiltieis further defined by the fish inspection act, the meat inspection act, the canada agricultural products act, the consumer packaging and labelling act
2012: all food safety laws consolidation under the safet fod for canadians
Strengthened protections against deception and tampering
Improved food traceability
Enhanced import controls and export certifications
To explain how food is involved in climate change
The greenhouse effect
Since the industrial revolution- human activities have artificially increased the greenhouse effect causing climate change
Greenhisue gagses (GHG) akak radiatively active gases (RAGs)
Water vapiur h2o
Carbon dioxide co2
Nitrous oxide n2o
Methane
Also since 1930s human made CCS and other flurinated gases
The contribution to climate change is:
The carbon cycle and burning fossil fuels
the methane from live stock farming
natural gas lines
nitrous oxide from synthetic fertilizer
fossil fuel combustion
CFC and other fluorinated gases
POPs
To define sustainability and explain why the global industrial food system is unsustainable
Sustainability is the ability to meet the needs of the present without compromising the ability of future generations to meet their needs
The global food system is unsustainable because economic development has prioritized quantity over quality and disregarded the harm to human health and the environment
Deforestation and destruction of ecosystems
Loss of biodiversity
Loss fertile soi
Water air pollution
Climate change
To discuss some possible changes toward the goal of sustainable food systems
Test Review/Questions
Politics shapes the food system by
Providing infrastructure, supporting scientific research, regulating trade
What canadian government department is tasked with food governance
Health canada
What is the aim of free trade agreements
To eliminate trade barriers
What is an example of trade barrier
A tariff an import quota, a subsidy
For the UN food security is:
A human right
What part of canada suffers form food insecurity the most
Nunavut
What foods did the USDA food pyramid recommend to eat in the largest amounts?
Bread, pasta, and cereals
How is the 2019 Canada food guide different from other food guides?
It recommends to limit the consumption of highly processed foods
What is sustainability
The ability to meet present needs without compromising the ability of future generations to meet their needs
The present food system is
Unsustainable
What is an example of a greenhouse gas?
Water vapour, methane, nitrous oxide
How does human activity change the carbon cycle
Moving carbon front he geological to the atmospheric compartment, increasing the absorption of carbon in the oceanic compartment
Lecture 12
Learning Goals:
To review the food labelling requirements in Canada
Canada food labels are regulated by
the food and drug regulations (under the food and drugs act)
The safe food for canadians regulations (under the newer safe food for canadian act as well as other acts relevant o food safety and food import-export)
These laws:
Prohibit deceptive labelling
Prescribe labelling requirements
Net quality of product
Identity and main palace of origin
For some foods, packaging date, bet before date and storage instructions
Ingredients and allergens
Nutrition facts
The canadian food inspection agency and health caada are responsible for defining and enforcing food labelling regulations
Food labelling changes
In 2015 of december there were changes made tot he lsit of ingredients and nutrition facts table on packaged food, part of the healthy eating initiative which also includes
The new canadian food guide
The elimination of artificial trans fats
Restrictions on marketing to children
Improving access to fresh food for northern isolated communities
And food industries had until 2021 to comply
To distinguish between labelling requirements and manufacturer’s claims
Ingredients must be listed by their common names in descending order by weight (except spices, seasonings other than salt, herbs, natural and artificial flavour, flavouring agents, food additives, vitamins, and minerals which can be listed at the end
In 2016 changes were made to make it easier to find read and understand the ingredients lists
There is a minimum type height, black font, using lower and uppercase, grouping based on ingredients, bullet to commas to separate ingredients, food colours listed by name and a white or neutral background
Nutrition facts table
It was unclear and now, the calories are larger and bolder with a line below it
serving size stands out more because it is similar on similar foods
Daily values updated
New % daily value for total sugars
Mg amounts are shown
New % daily value footnote
Updated list of minerals of public health concern
New % daily value for total sugars
Manufacturers claims on nutrient and diet related health claims
This is made more marketing purposes and and as a rule of thumb the more health claims it claims on the front label the less healthy the food is
To describe organic farming, outline its original goals, and discuss its institutionalization
Organic farming started in 1960s as grassroots movement that opposed the industrialization of agriculture, it used both environmentalism and social justice
Now organic foods are the fastest growing sector of food industry and its largely co opted by agribusiness
Institutionalized: national regulations and standards
Its large scale production and distribution contradict the original principales of organic farming in the first place nad institutional standard can only regulae a limites set of practices
To define the organic standards in Canada
The organic food standards in canada sicne 2009
Requires certification by CFIA rcognized bodies
Products with at least 95% certified organic content can be lablled as organic or have the organic logo
Products with 70-95% certified organic content can declare “containsn xx% organic ingredients
Products with less than 7-% organic content can only show organic claims in the products ingredients list
Canadian organic standards
Plants grown without pesticides, artificial fertilizers, sewage sludge
Animals grown without antibodies and hormones, fed organic feed, no animal byproducts, having access to outdoors
Processefd and packaged without synthetic additives and preswrvatives
Not irradiated
No GMOs and cloned organisms
To discuss the value and limitations of nutrition science
Its trustworthy since it comes form a systematic and peer reviewed researched, and the scientists are trained professional with evidence
Peer reviewed means that it goes under a lot of scrutiny and evaluation by many independent scientists before being oublcished
But human nutritionalstudies are didifuclt to carry otu and interpret sicne its realtviely yung, its complex and its evolving
To distinguish the various types of scientific studies used in nutrition research, and discuss their advantages and disadvantages
Types of nuturitonal studiesL
Observational, intervention, metastudies
Observational
Observations only, no interventions
Epidemiological studies: bservations of populations
Case studies: past histories of individual subject re examined
Cohort studieS: a group of subjects are monitoeed over a long period of time
Longitudinal, prospective/retrospective
Statistical correlations are possible indicators of cause-effect relations
Source of errors: sample size, duration of study, sampling bias, unreliability of self reporting, experimenter bias
Intervention
Intervention studies: intervention and observation
independent variable: possible cause of a health outcome actions are taken to isolate the effects of the independent variable to test a cause-effect hypothesis
subject group and control group
sources of error: sampling bias, subject bias (placebo effect), experimenter bias
Randomized controlled trials: random selection of subjects and control group
Double-blind randomized controlled trials, the “gold standard” of intervention studies
source of error: experimenter bias
metastudies
A meta study is a statistical analysis of data drawn from several previosu studies on the same matter
Sources errors: quantity and quality of studies examined, variations of experimental design, complexity of analysis
To identify some examples of controversial nutrition claims
Fad-diet claims: “Fat makes you fat”, “Low fat diet is healthy”, “Carbohydrates make you fat”
The Lipid Hypothesis:
To define two overweight parameters, BMI and waist size
Body mass index (BM<I) - body mass in Kg/(height in m)2
A healthy range is about 18.5 < BMI < 24.9
Obesity is BMI > 29.9
Bmi is a statistical measure and its not a aprameter of haltjh risk applicable to indidivuslas, there are biases since muscle mass is denser than fat, different corerelations with bodyfat for people of different heights, it not valid or younger/older people, breastfeeding or pregnant people either
Waist size as index of risk
Increased risk > 94cm for men and >80 cm for women
Substantially increased risk >102cm for men and >88cm for women
To discuss the question of the raising numbers of overweight and obese people in the contemporary world
The eat more environment: constant ready to eat products availability, advertising, portion distortion and supersizing
Industrial food production and processing
Adulterations and evirnmental toxins
Sedentary lifestyle
Stress
To conclude the course with a few simple guidelines to be an “enlightened eater”
“Eat food. Not too much. Mostly vegetables” (Michael Pollan)
Shop around the perimeter of the supermarket (Marion Nestle)
The Okinawan rule: Hara Hachi Bu (“Belly 80% full”)
Prefer fresh local food in season
Read labels
Prefer foods that are not advertised
Enjoy preparing and eating food with friends and family (by yourself too—why not?)
Test review/questions
What is the difference between labelling requirements and manufacturer’s claims?
Labelling requirements are mandatory, manufacturers claims permitted
What agenc or agencies is or are responsible for defining and enforcing food labelling regulations in Canada?
Canadian food inspection agency and health canada
What information msut be present on food labels in canada?
Ingredients list, nutrition facts table, main place of origin
What information must the nutrition facts table contain?
Kilacalories
What are the orginal goals of organic farming?
Protecting the environment
Why were official organic food standards defined?
To regulate the growing organic food market
Which of the following is part of the organic food standards in canada?
Grown without pesticides, grown without artificial fertilizers, no GMOs ad cloned organisms
What is a limitation of scientific research in nutrition?
Human nutrition is affected by many factors and experiments are difficult to carry out
What is the difference between an observational study and an intervention study?
In an intervention study an independent variable is isolated and controlled to test a cause-effect hypothesis
What is one type of observational study?
Case studie
What is one type of intervention studies?
Randomized control trials
What is a possible source of error in an observational study?
Small sample size, short duration, and experimenters bias
What is a possible source of error in a double blind randomized controlled trial ?
None, its seen as the gold standard
What is an example of a nutrition claim?
The lipid hypothesis, a high carb diet is less healthy than a high fat diet, foods of high glycemic index lead to diabetes, heart disease, and other diseases
What is a problem of using BMI as a measure of ideal weight of an individual
Muscle mass is denser than fat tall people tend to have lower BMI than short people, and it only applies to a limited group of people