topic 6 Flashcards
(39 cards)
what is organic food? How is it different from natural food?
- Organic foods: foods grown without synthetic fertilizers or synthetic pesticides and relying on natural means to control insects. No genetically modified components.
- Natural foods: ambiguous term w many meanings
why is it hard to grown organic in a large scale?
not enough manure to fertilize such large crops
what nutrients are needed in manure to grow crops? who figured this out?
Nitrogen (N), phosphorus (P), potassium (K)
Justus Von Liebig
What did Fritz Haber discover?
found a way to combine N and H to make ammonia synthetically. N2 + 3H2 –> 2NH3
ammonium nitrate
fertilizer as a good source of ammonia but can also be an explosive (Oklahoma City explosion). It decomposes into nitrous oxide (N2O) as greenhouse gas ☹ aka prevents heat loss and contributes to greenhouse effect (global warming).
difference between synthetic and natural pesticides
natural pesticides are unmodified from naturally existing plants/materials
synthetic pesticides are derived from materials, it has been modified or created in a lab
what are the only 4 genetically modified crops using recombinant DNA
corn, soy, canola, sugar beets
T or F: All foods we eat are genetically modified by cross breeding
True
T or F: organic = pesticide free
False, Organic agriculture uses registered, naturally-available pesticides ONLY. Eg. copper sulfate.
T or F: organic foods are more nutritious than conventional food
False, there is no evidence of a nutrient quality difference between the two. Nutrients do not depend on the latter, but rather variety type, soil quality, fertilizers, crop rotations, maturity at harvest, transportation.
health risks associated with natural and synthetic pesticides
no identified health risks for either, it is rather improper use (excess dosage) that causes risks
what kind of pesticides do we ingest the most
99.99% of consumed pesticides are natural, we consume ~ 1.5g of them/day, which is 10000x more than synthetic pesticide residues
Risks and benefits of DDT
Risks: Rachel Carson explained that DDT accumulated in the food chain which causes problems in the environment. Found to correlate with future breast cancer risk (but no prove of cause and effect), so no compelling evidence that influences cancer development
Benefits: reduced malaria in Africa
Malathion
synthetic pesticide that can wipe out mosquitoes that transmit disease and interfere with important enzymes in body if dosage is too high (can kill)
What is the Nocebo effect
Opposite of placebo effect, : if you believe something will do you harm, you can get physical symptoms.
Down side of pesticides…
Occupational exposure to pesticides can cause consequences, but amount of exposure is huge!
- Farmers might not wear proper equipment, settles in their clothes, and bring pesticides into their homes which in turn affects their family/kids. Common occurrence in southern U.S. where a lot of farmers are migrants.
- Incidence of Parkinson’s is higher in agricultural areas and might be linked to pesticides (but association is not = to cause and effect)
-Conclusion: while there are such hormonal effects, many chemicals affect hormones so it is v difficult to know whether pesticides which we are exposed to are having an effect on hormones.
why do people buy organic
- For what it doesn’t contain (pesticide residues) –> not true though
- For what it does contain (more nutrients) –> also no true
- Environmental benefits
Why do pesticides get a bad rap?
They have sometimes been associated with cancer and their improper use has caused deaths.
Round up
glyphosate: a pesticide used to kill weeds, made by Monsanto, sometimes weeds become resistance to it, very effective, DOES NOT cause cancer in humans
What is proposition 65?
California proposition 65: “Any substance that in any dose in any animal can cause cancer should be subject of a warning to the public”.
Are natural pesticides better for the environment than conventional (synthetic) pesticides?
It depends, it is a case by case issue. Eg. for soybeans, organic mineral oil had a worse record than synthetic
Why is synthetic pesticide use beneficial?
Allows for more specific killing use, less tillage, less energy intensive and less herbicide –> higher yield
What is the second most used technology in gmo foods?
insertion of gene into crop that codes for toxin that kills insects. eg. bt corn has gene from bacillus thuringiensis that allows for protection from corn borers. It therefore prevents the development of fumonisins, a fungus which is an established carcinogen.
Common GMO foods
canola, bt corn, gmo potatoes (survived colorado beetle), papayas, etc.
