fdsc2000 prelim 3

criteria for designating vitamins

cannot be synthesized in ample amounts in the body
Chronic deficiency is likely to cause physical symptoms
Symptoms will disappear once the vitamin level in the body is restored (However deficiency may cause permanent damage if it is too late)

Classifying vitamins

Classified based on solubility → affects absorption, digestion, transportation, storage, excretion

Water soluble: 8 B vitamins
B1 - Thiamin, B2 - Riboflavin, B3 - Niacin, B5 - pantothenic acid, B6, B7 - Biotin, B9 - Folate, B12, C

Fat soluble: 
A, D, E, K

Vitamin structure

All vitamins contain CHO, some contain N and S
Each vitamin is a singular unit
Vitamins are absorbed intact
Vitamins perform numerous essential functions → some have more than one role in metabolism

Absorption and storageof fat soluble vitamins

absorbed in the upper part of SI → except for K, which is mostly made by gut bacteria and can be absorbed in LI
Micelles in lumen → packaged in chylomicrons in enterocytes to enter the bloodstream
Lack of fat can lead to deficiency
More Stable

Liver mostly stores vit A, some K and E
Vit D stored in fat muscle and tissue
Since can be stored, can build up in body to point of toxicity

Absorption of water-soluble vitamins

Absorbed with water and enter directly into the bloodstream
Most absorbed in upper part of SI

Not stored, excess intake excreted in urine → must consume adequate amounts daily

Vitamins differ in bioavailability

Depends on
Amount in food
Preparation
Efficiency of digestion and absorption of food
Individual nutritional status

How vitamins are destroyed in cooking and storage + how to preserve

soaked/cooked in water → water soluble vitamins destroyed or dissolved
Changes in pH → affect Thiamin (B1) and C
Heat → affects mostly water-soluble vitamins, especially C

Veg and fruits lose vitamins almost immediately after harvest → some prep and storage methods accelerate loss

Fat soluble more stable than water soluble

Preserve be cooking in less water, lower exposure to heat, water, oxygen (less surface area), store in fridge, don’t rinse rice or pasta

How do vitamins act as antioxidants? + Oxidative stress

Vitamin E, beta-carotene, and C, phytochemicals, superoxide dismutase (requires Zn, Mn, Cu) are antioxidants

free radical = molecules with unpaired e- → unstable
Produced as by products of metabolism and from exposure to toxic chemicals, smoking, UV
antioxidants act as e- donors to stabilize free radicals

Oxidative distress = more oxidants (free rads) than antioxidants → high and chronic stress

Oxidative eustress = less oxidants than antioxidants → moderate and short-term stress

Oxidative stress = faster accumulation of free radicals that body can metabolize them → Damage DNA, body proteins, cell membranes → cell damage, disease, aging

Primary functions of water-soluble vitamins

B vitamins act as coenzymes in many metabolic processes → help enzyme to catalyze reactions to build or break apart compounds → transform CHO, protein, fat to ATP
recall B2 and B3 in TCA cycle and ETC

Other roles
antioxidant - C
nerve function - B1
Protein synthesis - B3
formation of RBC - B9, B12
Promote heart health - B vitamins

Food safety

includes safety from pesticides, additives, and microorganisms

Consumers mainly focus on microbiological quality
Many microorganisms can cause infections and produce toxins
Infection = ingestion of pathogens with food that may attack intestinal tract or produce toxin
Intoxication = production of a toxin by a pathogen in the food and then digested

Time from ingestion until symptoms is longer in foodborne infections than in foodborne toxins

Food safety in the US

one of the safest food supplies worldwide:

Federal and state regulations - FDA
Inspections - FSMA → food safety modernization act
CDC - Center for disease control and prevention → tracks down causal factors upon outbreaks of foodborne illness (relies on reports from local agencies)
Voluntary recalls: food manufacturers and distributors can avoid lawsuits due to negligence

Foodborne outbreak and foodborne illness

Foodborne outbreak CDC definition: occurrence of two or more cases of a similar illness resulting from the ingestion of a common food

Foodborne illness: illness transmitted to humans by food
can also be caused by human errors (like improperly preparing food item or cross contamination)

Food recall causes and classes

Occurs due to discoveries of:
Organisms like bacteria or parasites
Foreign objects like broken glass or metal
Major allergens that do not appear on product label

Class I:
Most severe, reasonable probability that will cause serious adverse health consequences or death

Class II:
Reversible adverse health impact, remote chance for serious consequences

Class III: 
Least serious → labeling mistakes, health impacts unlikely
if its just a labeling mistake they can just repackage the product and sell it

Basic categories of food safety hazards, conditions that create food safety problems

Physical, chemical (like pesticides or additives), biological (microorganisms)

Conditions that create food safety problems:
Transmission of disease germs via food → cause illness from infection or toxins
Gastroenteritis caused by ingested bacteria
Illness caused by agents other than microorganisms → like tuna and mercury

High-risk foods and individuals

Potentially hazardous foods:
Moist, high-protein, low-acid

Immune system helps fight infection → but most vulnerable are
Infants and children, elderly individuals, immuno-compromised individuals, pregnant women

All things are poisonous!! the dose makes things safe

Cross contamination

transportation of harmful substances to food by:
Hands that touch raw foods
Cutting boards or cleaning cloths
Fluids
Improper storage

Pathogens

Harmful microorganisms
Ex: viruses, parasites, fungi (yeasts and molds), bacteria
STEC = shiga toxin-producing e. coli
Of the 15 leading foodborne pathogens, Norovirus sickens the most people

The greatest threat to food safety…bacteria

What even are bacteria?! How are they classified ?!

Single-celled, living organisms that grow quickly

Vegetative cell = their normal active state
Not all bacteria are pathogens → some are useful !! → gut microbiota
Some are pathogens tho (Booo) → infectious disease-causing

Classified by shapes: 4 most common
Cocci = spheres → some spheres can stick together
Bacilli = rods
Vibrio = coma shaped (squiggly guys)
Spirilla = spirals (have fun hair)

Bacterial spores

Some bacteria, not all, transform into spores as a survival mechanism or protection from a harsh environment → ex: when nutrient sources (C and N) are depleted) → these spores are more resistant to higher temperatures and toxic chemicals than their corresponding vegetative cells (very tough guys, outer shell more resistant) → at favorable conditions, the spores can be reactivated and turn into bacteria

Factors influencing microbial growth

FATTOM acronym
Food
Acidity → bacteria survive within specific ranges → acidophiles (low pH), Neutrophiles, Alkaliphiles (high pH)
Temperature → psychrophiles (low temps), mesophiles (medium temps), thermophiles (high temps), hyperthermophiles (very high temps)
Time → need enough time to grow
Oxygen
Moisture → water activity = measure of water available for bacterial growth, 0.85 = minimum for bacterial growth (idk if thats true.. maybe check the slides later)

We can control TT → time and temperature the most
Time-temperature abuse = food that has been allowed to remain too long at temperatures that favor growth of foodborne microorganisms → you should not eat that

Time and bacterial growth

4 phases of growth vs time
Lag phase (no increase) → log phase (exponential growth) → stationary (environment self-limiting → plateau in growth) → death or decline phase (exponential decrease)

Oxygen and bacterial growth

anaerobic organisms → oxygen is not necessarily required for some bacteria"

Obligate aerobes → love oxygen, aggregate to top of test tube exposed to air
Obligate anaerobes → hate oxygen !!! booo, bottom of test tube dwellers
Facultative anaerobes and aerotolerant anaerobes → both don’t mind absence or presence of oxygen, facultative prefer some oxygen tho
Microaerophiles → like oxygen, but not too much

Listeria Monocytogenes: Where its found, its characteristics, common foods, prevention, high risk pops

Causes listeriosis, found in soil, water, plants
Unique characteristics → its a tough guy:
grows in wide temp range (4-45C) → survives refrigerator temps, even frozen dairy deserts
Facultative → can grow with/without oxygen
Can survive a wide pH range (4.8-9.0)

Foods commonly linked with listeria outbreaks → raw meat, ready-to-eat food (like salad packets), unpasteurized milk/dairy products (recall how listeria jumps across cells!!)
Prevent: cook raw meat to min internal temps, avoid cross contamination b/w raw and cooked foods

High risk pops: Usual 3 - elderly, infants, immunocompromised
+ pregnant women (can lead to miscarriage) and fetuses/newborns (can reduce life span and health status) → recall that Listeria can jump b/w cells/barriers → travels through the body → can pass blood-placental barrier b/c of its actin-powered tail

Listeria Monocytogenes: how it infects and multiplies in the body

Infection:
1. Listeria induces entry into a non-professional phagocyte (like epithelial cells) → 2. bacteria becomes internalized in a vacuole (AKA phagosome) →
3. membrane of vacuole is disrupted Listeria secreting phospholipase C (PLC) and pore forming toxin listeriolysin O →
4. bacteria released into cytoplasm, where they multiply and start to polymerize actin, forming actin tails →
5. Actin polymerization allows bacteria to pass into a neighboring cell by forming protrusions in the plasma membrane →
6. Enters neighboring cell through a double-membrane vacuole, repeats cycle (check slides)

Toxin-producing bacteria in food

Bacillus cereus clostridium botulinum, staphylococcus aureus

Endotoxins: released after bacteria death
Exotoxins: secreted into surrounding environment

Clostridium botulinum

Produces the botulism toxin, causing botulism (wow who would’ve thought)

A very delicate and picky guy…
Obligate anaerobes → HATES OXYGEN!!, but not necessarily killed in presence of O2
Can’t grow well in refrigerator temperatures, high acidity, or low moisture
Form spores a lot → their spores are temperature and O2 resistant

Foodborne botulism:
When intoxicated: causes not gut-related symptoms → nausea and vomiting (nerve reactions), double vision, difficulty speaking and swallowing

Commonly linked with contaminated canned food, reduced oxygen packaged food, time/temperature-abused foods

C. Tetani vs C. Botulinum

C. Tetani:
Blood borne, not foodborne
Causes tetanus, generally fatal, toxin affects CNS, causes spastic paralysis 
Infects deep wounds, vaccine available

C. Botulinum:
Foodborne
Causes botulism, potentially fatal, one of the most lethal substances - LD50 = 1ng/1kg
LD50 = lethal dose for 50% of people
Causes paralytic death, rare occurrence, anti-toxin available
Botox :O

Viruses

Microscopic infectious agents that can reproduce only inside a host cell → need energy source (ATP) to reproduce

They do not cause spoilage in food, but may still be present → can’t tell if a food has a virus on it → can contaminate both food and water
→ cannot grow in food, but can “grow” in a person’s intestines
→ don’t die because they were never alive… not a complete cell, cannot perform regular cell functions → that’s why they need host cell
→ CAN be denatured/inactivated, NOT KILLED !!

Some can withstand refrigeration and freezer temps (heat- and cold- resistant)

they kinda just exist in the environment 

Norovirus: Where its found, how you get it/how its transferred

Causes Norovirus gastroenteritis → affects intestines
Most common “popular” gastroenteritis in the world

Usually found in ready-to-eat food, contaminated water
Commonly uses the fecal-oral transfer route (like if not washing hands after pooping and then eating with those hands) → WASH YO HANDS

Self-limiting for the majority of people → people will get better after a few days, but the virus will still be in their poop for days after symptoms end

Small amounts can make a person sick, very contagious, cannot build immunity to it

Outbreaks often occur in closed communities → lots of people, confined space (ex: college dorms, cruises #1)

Fungi and Aflatoxins

Can be microscopic or as big as a giant mushroom

Molds and yeast are both fungi → some produce toxins, others are beneficial (like the ones we eat - baker’s yeast/saccharomyces cerevisiae, or penicillium)

Aflatoxins: produced by Aspergillus species of mold
four major types → B1, B2, G1, G2
carcinogenic
Toxins are highly thermostable
Caused by poor storage/weather conditions
Causes estimated 25% loss of food supply
Most famous outbreaks: corn and peanuts due to storage, if moisture seeps in
Can be visually seen, but spores travel easily → softer foods do not eat if has mold !!!

Toxins = known structures, can be natural or manmade
biological toxins are made by living organisms

Parasites: What are they, prevention, in the body

Need to live on or in a host to survive → no benefits from host, steals host nutrients
Ex: Trichinella spiralis (trichinosis) found in pork products, Anisakis roundworm or cod worms

Prevention:
Buy food from approved and reputable suppliers
Most commonly associated with pork (raw meats), seafood, or contaminated water → less likely to show up in foods that go through additional processing

In the body:
Much of them damage the intestines
Some may bite into intestinal lining to feed → chronic bleeding, may see parasites in the stool

Thermal processing and Microbial destruction

Thermal processing: used to keep microbial loads at minimal levels to provide safe foods while also keeping quality high

2 general thermal processes: heating to a specific temp for a specific time to reduce microorganisms
Pasteurization: decrease vegetative pathogens
Comm. Sterilization: decrease spore-forming pathogens → much harsher

Microbial destruction: a logarithmic event, much like microbial growth phase → neither process kills all microorganisms in food, only lowering their amount

Microbial methodology

SPC - Standard plate count: a laboratory test for total number of viable aerobic and facultatively anaerobic microorganisms in foods
→ a quality indicator used to set microbial standards
→ low SPC does not always mean a safe product
→ FDA generally requires no infection causing microorganisms (like listeria, E. coli, etc) can be recovered from 100g of food after suitable incubation
→ presence of E. Coli is used as an indicator of potential for the presence of pathogens since its so commonly found

Cleaning: methods, biofilms, solubility properties

The complete removal of food soil

Categorized cleaning methods:
Mechanical cleaning (CIP) → most general, generic → like a car wash, run through a mechanical pipeline of cleaning tools and solutions
Clean out of place (COP) → more detailed → localized, some things may be disassembled to clean → cleaning parts separately, like your water bottle
Manual cleaning → most detailed, deep cleaning → physical disassembly to clean every little piece

Microbiological biofilms: built up in environment and in our mouths
Essentially layers and layers of microbials growing → these need extra solutions or harsher detergents to clean → may need manual cleaning

Solubility properties: soils may be classified as…
Soluble in water (sugars, salts, some starches)
Soluble in acid (mineral deposits)
Soluble in alkali (protein, fat)

Sanitization

2 types of methods
Thermal (heat) → uses water or steam
Chemical → approved for food-contact surface applications, specific concentration and contact time → some concerns about residuals tho

Hot-water sanitizing involves immersion, spray, and circulating systems

Consider the effects of impurities, like the hardness of water

Why doesn’t honey go bad?

Recall FATTOM:

Moisture is a big reason why honey doesn’t go bad. It has a low water activity since there is so much sugar → lots of the water in honey gets bound to sugar molecules, so there is not a lot of free water to support microbial growth.

HAACP and food safety: the 7 principals

HAACP = Hazard Analysis and Critical Control Point

1. Conduct a hazard analysis
2. Identify critical control points (CCP) → pt in production process in which control is applied to prevent, eliminate, or reduce safety hazards
3. Determine the critical limits/establish preventative measures
Critical limit = maximum or minimum value in which a safety hazard can be controlled
4. Define monitoring procedures → processes that ensure every process is under control at each CCP
5. Implement corrective actions → when a deviation in a critical limit occurs
6. Establish verification procedures → to ensure plan is successful
7. Create record keeping procedures 

“what gets measured gets managed"

Graph of critical limits principal 3

Food quality: consumer choice, what does it depend on, who controls it

price, availability, religion, preference affect consumer food choice → they want high-quality, nutritious, safe, for best value

Quality depends on food composition, handling and processing, packaging and storage → must control microbiological spoilage, enzymatic degradation, and chemical degradation

USDA - AMS (agricultural marketing service) establishes quality and grading standards → develops and maintains descriptions for commercial food items

Programs like HACCP, TQM (total quality management) and CGMP (current good manufacturing practices) monitor and maintain food quality

Sensory evaluation

The process of human analysis based on appearance, taste, smell, sound, feel of food 

Everybody is different → consumers have certain expectations about different food

Appearance

2 categories:

Color attributes
Subjective index: compared with standardized color tiles
Objective index: precisely measured by tristimulus colorimetry in terms of value, hue, and chroma
hue = pure color name, value = brightness, how light or dark, chroma = intensity

Geometric attributes
Size and shape: depends on product
Electronically measured and recorded

Textural factors

Refers to qualities that can be felt with fingers, tongue, or teeth

Texture is a mechanical attribute, quantified by:
Sensory means
Physical (rheology) measurements: rheology = study of flow

Mechanical testing:
Based on actions of stress and strain → viscometer, penetrometer, Warner-Bratzler shear press, etc

Various methods to control texture:
Lipids are softeners and lubricants, starches and gums are thickeners, protein can also be a thickener, sugar can add body or chewiness

Taste vs flavor

5 primary tastes. These cannot be broken down further:
sweet, sour, salty, bitter, umami (like msg)
Different people can have different number of taste buds → not all people detect all five tastes to the same level

Flavor describes sensations perceived by the tongue (taste) and nose (smell)
Other characteristic flavors: fruity, hot (capsaicin), sulfurous, astringent (dry, chalky)

Judgment of flavor is influenced by:
Color and flavor
Bacteria, yeast and molds, enzymes, moisture and dryness, light, additives

Taste panels

the ultimate test → sensory evaluations typically ask for
Appearance
Mouthfeel → flavor and taste
Aroma
texture
Aftertaste → residual, may be different from taste
Taste “fatigue” → if you keep tasting same attribute, brain stops responding

Some of these categories can be eliminated by the design of a sensory evaluation room: like clamping noses, changing color lighting to mask food sample color

Additional Quality factors

A product’s storage or shelf life can be extended via: heat treatment, irradiation, refrigeration, freezing, drying, controlling water activity → these also impact food quality especially via effects on food components like proteins, fats, carbohydrates, vitamins, and on microbiological characteristics

Proteins: heat denaturation, light-oxidation → staling
Enzymatic degradation of protein causes changes in body and texture and may produce bitter flavors from peptides and amino acids
Freezing alters protein conformation and solubility

Lipids: similarly, oxidized stale smell comes from lipid oxidation → this is from the smell of volatile short chain fatty acids. Longer chain acids produce a soapy flavor but are less volatile, so less noticeable smell

Hydrolytic rancidity → hydrolysis of triglycerides into one or more free fatty acids from glycerol → these fatty acids are stinky

Oxidative rancidity: Begins with formation of free radicals from unsat FA → these bonds become unstable. This is less of a problem with saturated lipids

free radicals from unsat FA due to light → hydrocarbon free radicals form peroxide radicals → these abstract H from other substrate molecules to form hydroperoxides