EESA10H3 Lecture Notes - Lecture 8: Spinach, Immunodeficiency, Clostridium
5 Jul 2018
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LECTURE #8
FOODBORNE HAZARDS AND HUMAN HEALTH
-Food production
Fertilizers
Pesticides
-Transmissible diseases
Bacteria (eg. E. Coli, salmonella, Listeria, botulism)
Viruses
Parasites
-Non-transmissble diseases
Shellfish associated toxins
Color aditives
Obesity
Diabetes
-Organic food
-GMO
Use of chemical fertilizers
-Use of nitrates in fertilizers lead to nitrites in ground water
-Direct human health effect
oNitrites in water change hemoglobin to form that cannot carry oxygen
oIn water have nitrate
oIn stomach, it changes to nitrite causes methemoglobinemia
Use of chemical pesticides
-Pesticide = chemical used to kill pests
Active ingredient = the one intended to kill the pest
-What is a pest? a cultural category
Eg. Squirrels/rats come from same category, but pests are the one that carry disease
-Insecticides
Inorganic compounds
oPytrethrum from Chyrssanthemum
oOrganochlorine insecticides (eg. DDT, chlordane, Aldrin, dieldrin, heptachlor)
oNeurotoxin, low acute toxicity
oPersistent and bioaccuulative
oBanned in developing countries
Organophosphates
oNeurotoxin (not persistent in env.)
oAcute toxicity to people varied wiedly
Carbamates
oChemical action similar organophosphate
Pyrethroid (pyrethrum-like) insecticides
oLow acute toxicity to people
oused in some consumer products
find more resources at oneclass.com
find more resources at oneclass.com
-Herbicides
Selective herbicides
oKill broad leaves plants, do not kill grass (eg. Corn, grain)
oKill weeds from wheat/corn fields common in agriculture
oUsed as a defoliant (selectively make leaves fall outside of regular season)
In military context, use to kill large plants that can provide cover to
enemy
Non-selective herbicides kill all plants
oEg. Monsanto’s roundup
oRoundup ready GMO soybeans
-Fungicides (in agriculture)
-Rodenticides (often anti-coagulant bait)
-Limitations of pesticides
oResistance
oSome pests resistant (genetic makeup)
oResistant indiv. Survive and breed resistance is passed to new generations
and pesticide becomes useless (kind of like antibiotics)
-Human health effects of pesticides
Difficult to study chronic effect (eg. Law suits for round up)
oDifficult to assess exposure accurately
oChanging mix of chemicals (exposed to new chemical every couple of years)
oWorkers lack information (farmers don’t know, don’t know if wear new gear
etc.)
oVariation in practices, protective gear (eg. Should spray more, spray less
eg. If liquid can have inhalation, solid = dermal exposure)
oHard to sep. acute/chronic effects ( how do we know how long it wil require
exposure to be dangerous)
Neurologic/reproductive effects; cancer
-Disparities in exposures and impacts
Pesticide production workers
Farmers and their faimilies
Hired farmworkers in US, mostly men, half Hispanic/half-foreign born
Often inadequate protections, faciliites, warnings (eg. Might be seasonal workers,
don’t get protection, information etc.)
-In lower-income countries; more hazardous pesticides may still be in use (eg. May be
cheaper so buy from black market, could may not be effective, but still be harmful)
Transmissible Foodborne Illnesses (illness can pass from host to another host; MOs)
-Types of food
Meat, milk, dairy, unpasteurised fruit/veggies, raw eggs, chicken, tuna, potato, cream
fresh produce, spices, seafood
Mostly proteins, carbs, fruits/veggies
-Careless food handling
find more resources at oneclass.com
find more resources at oneclass.com
Food standing too long at room temp.
Improper cooking
Contaminated cutting boards
and kitchen tools
Clean with detergents (eg.
Bleach) never cut fresh
meat and fruits on the same
cutting board
oWood vs plastic
wood is better for
cutting boards (have
natural chemicals
that disinfect as well)
-low-socio economic groups +
children are at greatest risk,
unsanitary conditions, eating out,
elderly
Symptoms
-diarrhea, abdominal cramping,
fever, vomit, blood in stool
-lasts 1-2 days or 7-10
-usually not life-threatening
-severe for young children, the very old and people w/ certain disease and conditions
such as liver disease, iron disorder, diabetes, cancer
Prevention
-safe storage, food prep, clean, hot food hot/cold food cold, cook properly, propoer
storage of leftovers, wash your hands
Bacteria: E. Coli
-food poisoning usually associated w/ eating unwashed veggies and meat contaminated
post-slaughter mostly in meat
-grounded beef (increased S.A, grinding is longer, contamination potential is longer)
-diarrhea, abdominal cramps (can also be from water)
-complications: hemolytic uremic syndrome RBCs are destroyed, kidneys fail (2-7%
cases)
Bacteria: Clostridium Botulinum
-rare, but serious illness (fatal)
-nerve toxic of bacterium botulinum
-caused by the toxin, not by the bacterium itself
-commercially canned foods should undergo botulinum cook in a pressure cooker at
121*C for 3m normally lives in soil and can be on the plant
-home-canned foods
-unusual sources: storing in things like oil activates them from spore state
garlic or herbs stored covered in oil
improperly handled baked potatoes wrapped in al. foil put in ground,
botulinum can enter the potato once it grows (b/c warm env)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Bacteria (eg. e. coli, salmonella, listeria, botulism) Use of nitrates in fertilizers lead to nitrites in ground water. Direct human health effect: nitrites in water change hemoglobin to form that cannot carry oxygen, in water have nitrate, in stomach, it changes to nitrite causes methemoglobinemia. Pesticide = chemical used to kill pests. Active ingredient = the one intended to kill the pest. Squirrels/rats come from same category, but pests are the one that carry disease. Inorganic compounds: pytrethrum from chyrssanthemum, organochlorine insecticides (eg. ddt, chlordane, aldrin, dieldrin, heptachlor, neurotoxin, low acute toxicity, persistent and bioaccuulative, banned in developing countries. Organophosphates: neurotoxin (not persistent in env. , acute toxicity to people varied wiedly. Pyrethroid (pyrethrum-like) insecticides: low acute toxicity to people, used in some consumer products. Selective herbicides: kill broad leaves plants, do not kill grass (eg. corn, grain, kill weeds from wheat/corn fields common in agriculture, used as a defoliant (selectively make leaves fall outside of regular season)
