Food Sci Midterm 3

types of food hazards (from lowest to increasing concern by regulatory agencies like FDA, CDC)

food additives, pesticide residues, natural toxicants, environmental, nutritional, microbiological (opposite order for increasing concern by public and news media)

very toxic dosage

50-500 mg/kg

2 toxins made by glycoalkaloid

solanine and chaconine

microbial death

decrease in numbers

Clostridium botulinum

gram positive anaerobic bacteria, ubiquitous in soil, spore forming bacteria, produces Botulinum Toxin: Neurotoxin

what conditions allow botulinum toxin to be produced?

-absence of air (since C. botulinum is obligate anaerobe)

-water activity must be >0.9 (water makes bugs grow, salt and sugar inhibits growth bc of water binding/osmotic properities)

-pH > 4.6

-nitrite: NaNO2 has inhibitory effect

Rotavirus disease

self-limiting, mild to severe gastroenteritis: vomiting,

watery diarrhea, and low-grade fever

Harvey Kellogg

-devoted to creating healthy food items for his patients

-advocate of vegetarianism and exercise, advocated low calorie diets (peanut butter, granola, toasted flakes)

-exploited 7th day adventists

-in charge of Sanitarium

-1st millionaire from selling health foods

Greeks

used toxins in the treatment of certain diseases/rational medicine (Hippocrates, Aristotle, Theophrastus)

Cleopatra

-experimented with strychnine and other poisons on prisoners and poor

-committed suicide with an Egyptian Asp (cobra)

Paracelsus

-father of toxicology

-alchemist, physician, astrologer, general occultist

-says that "all substances are poison"

Catherine de Medici

-wife of Henry II

-used poisoning as political tool during her reign

-early experimental toxicologist: experimented poisons on on sick and poor, disguised as "feeding" and "assistance"

-"mother of French cuisine" according to cooking historians

-original wearer of high heals and lip gloss

chemical types

inorganic, radioactive

biological toxin types

Clostridium Botulinum toxins, Staphylococcus aureus enterotoxin

example of radioactive chemical

selenium in brazil nuts

example of clostridium botulinum toxin (biological toxin)

botulism in canned foods

example of staphylococcus aureaus enterotoxin (biological toxin)

salads, meats

physical toxin

due to their physical nature, they interfere with biological processes

example of physical toxin

water

toxicity

capacity of a substance to produce injury

hazard

probability injury will result from use of a substance in a prescribed quantity and manner (hazard includes levels/how much, hazard=exposure x toxicology)

true/false: Once Salmonella enters your bloodstream, you suffer from sepsis and this can be deadly

true

food toxicology

the study of the adverse effects of poisons associated with foods in living organisms

why we study food toxicology

food and drink are primary exposure to chemical and bacterial toxins (since we eat 3 meals a day and drink fluids)

Shen Nung

-father of Chinese medicine

-wrote treatise "on herbal medical experiment poisons"

-died of toxic dose

Ebers Papyrus

oldest preserved medical doc from ancient Egyptian record (has anatomy and physiology, toxicology, spells, treatments recorded on papyrus)

Hebrew biblical description

Hebrews suffered mass food poisonings and deaths through eating quails

why did Hebrews die from eating quails?

quails fed on hemlock seeds and they are resistant to hemlock but humans are not

example of inorganic chemical

heavy metals: mercury in fish

safety

freedom from danger, injury, damage

toxicant

substance which when ingested at high levels produces harmful actions on biological mechanisms

nutrient

substance which when not ingested in sufficient amounts, produces harmful actions on biological mechanisms

LD50

statistically determined value that estimates dose required to kill 50% of population

practically nontoxic dosage

>15000 mg/kg

slightly toxic dosage

5000-15000 mg/kg

moderately toxic dosage

500-5000 mg/kg

extremely toxic dosage

5-50 mg/kg

supertoxic dosage

acute toxicity

disease with rapid onset or short course

chronic toxicity

disease that is persistent/otherwise long-lasting in its effects; occurs over a long period of time

example of acute toxicity

agent orange

dioxin

-super toxin

-can act as acute toxin or long-term chronic toxin

agent orange

-herbicide used in Vietnam

-sprayed many soldiers and victims

ichtytoxicology

seafood toxins, paralytic shellfish poisoning

fugu

made usually by licensed chefs in sushi bars/restaurants from fish in the tetraodontidae family (puffer-fish, blowfish, boxfish)

pufferfish can make a deadly toxin called...

tetrodotoxin (can inflate with h2o/sometimes air; when they are frightened/something angry/aggressive)

paralytic shellfish poisoning

-shellfish eat dinoflagellates, which accumulate saxitoxin, and people will get sick when they eat the shellfish

-cooking doesn't destroy the toxin

symptoms of paralytic shellfish poisoning

tingling and numbness, paralysis, respiratory depression, circulatory failure

treatment for paralytic shellfish poisoning

no antidote but treatment includes promotion of emesis, charcoal, artificial respiration

what does shellfish eat that make people get sick?

dinoflagellates (unicellular algae)

what type of toxin is created by dinoflagellates?

saxitoxins

shell fish (filter feeders)

mussels, clams, oysters

second metabolites produced by plants

waste products, intermediates in metabolism, protective mechanism

glycoalkaloid

toxins from plant genus solanacea; nightshades

nightshade family

tomatoes, potatoes, eggplant, peppers

green potato poisoning

-toxin: solanine (green caused by chlorophyll which shows potato was exposed by sunlight, increased sunlight=increased solanine)

-found in green potatoes (high levels in new sprouts and eyes of potato, low levels in skin)

cyanogenic glycosides

has cyanide triple bond, hydrolytic products

types of cyanogenic glycosides

cassava, lima beans, flax and seeds of almonds, apricots, plums, peaches, etc

peach pits with cyanogenic glycosides

HCN is part of amygdalin and enzymatic action releases HCN which interferes w/cellular respiration

cassava

-Africa largest consumer/producer

-cyanogenic glycosides are removed before cassava is eaten: roots are scraped/grated, properly soaked in h2o, finally fermented for a few days

hamburger paradox

-undercook=pathogens

-overcook=carcinogens

polycylic aromatic hydrocarbons

produced by excessive heating of meat (aromatic refers to the way double bonds are arranged)

polyaromatic hydrocarbons

prevents microbial problems by cooking food in high temps to kill microorganisms but has carcinogenic agents, mutagens

most important detoxification organ

liver

detoxication mechanisms

liver, immunities through homeopathic practices, tolerance to a poison is acquired by taking gradually increased doses of it (ancient Turkey ways)

most common overall cause of foodborne illness in U.S

novavirus

foodborne disesases

bacteria, parasites, viruses

microbial growth

increase in numbers

microbial survival

no increase or decrease in numbers

microbial foodborne diseases

infections, intoxications

foodborne intoxications

-relatively acute illness

-organism must grow in food but not grow in you

examples of foodborne intoxications

Clostridium botulinum (classic barf), Staphylococcus aureus (deadly), Bacillus cereus (emerging pathogen), etc

Botulism

caused by botulinum toxin: neurotoxin, heat-labile protein, toxin is resistant to proteolytic enzymes in GI tract

why do we add nitrites to food?

taste, to fix color (pink), inhibit growth of Clostridium botulinum

concerns about nitrites

-now generally recognized that nitrites don't cause cancer

-can make nitrosamines which are carcinogens at high levels

-food scientists keep nitrosamine levels very low and thus they don't cause cancer

prevention of botulism

-pH>4.6

-refrigeration at <40 degrees F

-hygienic food handling

-heat food to boiling temperature for 10 minutes (toxin is heat labile protein)

major sources of botulism poison

-low acid foods (ex: veggies like green beans, fish like salmon, meats)

-insufficient processing of processed foods

types of microbial food poisoning

infections, intoxications

foodborne infections

illness caused by infection, in which pathogen colonizes/takes over body

salmonella

gram negative facultative anaerobic bacteria, can survive for weeks in dry environment and several months in h2o, causes salmonellosis (symptoms: fever, gastroenteritis, septicemia)

salmonellosis prevention

hygienic food handling, high temps for cooked food, rigid temp control and hygienic practices for processed foods

e coli

gram negative facultative anaerobic bacteria, intestinal/commensal, found in feces, detection of e coli in drinking h2o/food is indication fecal contamination

odwalla story

made and marketed unpasteurized fruit juices which led to poisoning

chipotle story

2 outbreaks, linked to norovirus and salmonella outbreak, CDC investigators couldn't find source of infection, Chipotle identified Australian beef as source of contamination

parasite

an organism that lives in another organism, called the host, and often harms it (depends on its host for survival)

example of parasites

Giardia spp, Cryptosporidium spp, Cyclospora spp

Trichinellosis

-Trichinella spiralis (trichina worm)

-from undercooked pork, bear, dog, cat (rare in the U.S)

-killed by freezing 3 weeks

Anisakiasis

-Anisakis simplex (a nematode=roundworm)

-sushi parasite

-undercooked fish

-killed by freezing at -20 degrees C, 24h

-fish can be inspected/farmed

virus

-not alive

-grow in body (host) not food

-have no metabolism, no energy source, no metabolic waste

-hard to treat and diagnose

virus structure

-genetic material (dna/rna) is covered by a protein coat (capsid)

-hijacks host's genetic and protein synthesis apparatus and forces it to make more virus particles (virion)

how do viruses spread?

-disease is from infection (no toxin)

-infected people "shed" virus particles generally in feces

-normally spread through food handlers when they don't wash hands (fecal oral route for infection is most common)

Hepatitis A disease

mild illness: sudden fever, malaise, nausea, anorexia, abdominal discomfort, followed in several days by jaundice

Hepatitis A transmission

person-to-person contact through fecal contamination

Hepatitis A risk foods

water, shellfish, cold cuts, salads, anything handled by infected individuals

Rotavirus transmission

asymptomatic rotavirus excretion exists

Rotavirus risk foods

water, shellfish, cold cuts, salads, fruits, handled by infected individuals

Norovirus disease

self-limiting, mild, gastroenteritis: nausea, vomiting, diarrhea, abdominal pain, headache, low-grade fever

Norovirus transmission

fecal-oral route

Norovirus risk foods

water, raw, under-steamed shellfish, any foods handled by infected individuals

Aerosol

solid or liquid particles that can contain viruses and chemicals suspended in air or other gaseous environment