Food Safety and Technology: Microbial Threats and Genetic

EngineeringBIOL 103, Chapter 14

Today’s Topic

• Food Safety• Food Technology• Genetically Modified Foods

Food Safety

• Harmful substances in foods– Pathogens (disease-causing)

– Foodborne illness:1. Infection from pathogen2. Toxin produced by microorganism• CDC: “48 million Americans become sick, 128,000

require hospitalization, and 3,000 die from foodborne illnesses).”

Food Safety

• Harmful substances in food pathogens (Table 14.1: Common Foodborne Pathogens and Illnesses):

Pathogens Common Source Illness Symptoms

S. aureus Vomiting, abdominal cramps

C. botulinumFatal to infants

Salmonella Diarrhea, Vomiting, Abdominal cramps

E. coli Watery or bloody diarrhea, Death

Food Safety

• Prions: self-reproducing protein particles that can cause a disease such as…– Mad Cow Disease or Bovine spongiform

encephalopathy (BSE): a chronic degenerative disease that affects the CNS of cattle.

– Cooking and irradiation do not kill or deactivate abnormal prions.

Food Safety- Harmful Substances in Food

• Chemical contamination– Pesticides

• Important role in food production

• Concerns: 1. Pollution of soil

and water2. Threatens

wildlife• FDA collects samples

and analyzes food samples and animal feeds for illegal pesticide residues.

Food Safety

• Organic alternatives to chemical contamination in foods– There is no scientific evidence that genetic

engineering and irradiation of foods present unacceptable risks

– “USDA Organic” seal– Concerns regarding natural fertilizer– Can use approved synthetic and natural pesticides

to control weeds and insects– Microbial contaminants still found

Food Safety

• Animal drugs1. Antibiotics to maintain animal well-being, but

overuse can develop antibiotic-resistant microorganisms illness in humans

2. However, drug residues may enter human food drug allergies or illness in humans

• Pollutants1. Animal manure, factories wastes/dioxins, human

sewage can contaminate food production areas

Food Safety: Harmful Toxins

• Natural Toxins– Aflatoxins:

– Ciguatera: • Cooking does not destroy these toxins.

– Methyl mercury:

– Poisonous mushrooms: – Solanine:

Figure 14.5 Toxins in the food chainAs toxins travel up the food chain, they become concentrated in larger fish.

Figure 14.7 Government agencies that help protect our food supplyAlthough the FDA has primary responsibility for the safety of much of our food supply, many government agencies provide oversight.

Keeping Food Safe: Government Agencies (Pg587-588)

1. FDA: enforces laws governing safety of ____________________ food, except meat and poultry.

2. CDC: monitors/investigates outbreaks of ________ _______________and determines proper prevention

3. USDA FSIS: enforces laws governing safety of domestic and imported ________________ product.

4. USDA CSREES: develops research and education programs on ______________for farmers/consumers

5. EPA: regulates public ___________, approves _________________and other chemicals used in the environment.

Keeping Food Safe: Consumer

• Keep hot foods hot and cold foods cold

1. Clean2. Separate 3. Cook 4. Chill (refrigerate

promptly)

Risk for Foodborne Illness

1. Immune disorders (e.g. HIV infection)2. Cancer 3. Diabetes4. Long-term steroid use, such as for asthma

or arthritis5. Liver disease6. Hemochromatosis (iron storage disorder that

affects the liver)7. Stomach problems (e.g. low stomach acid)

Food Technology

• Food preservation– Preservatives

1. Salt, sugar –Most common

antimicrobial agents

2. Antioxidants– prevents changes in

color/flavor caused by air exposure

Food Technology

• Other preservation techniques1. Salting2. Fermenting3. Drying 4. Canning 5. Heating (e.g. pasteurization) 6. Irradiation – controversial

Food Technology

• Irradiation – food is exposed to measured doses of radiation to reduce or eliminate pathogens and kill insects, reduce spoilage, and in certain fruits/vegetables, inhibit sprouting and delay ripening.

• Why are food manufacturers reluctant to use this method of preservation?

Food Technology: Irradiation

Food Technology

• Bacteriophage– “Bacteria eaters” – viruses that infect bacteria– Sprayed on ready-to-eat meats and poultry

products to protect people from bacterial infections

• Infect only bacteria and do not bother mammalian or plant cells

– Must declare “bacteriophage preparation” on label of meat/poultry product

Genetically Modified Foods

Traditional Breeding• Cross two plants and

develop hybrids• Takes time

Genetic Engineering• Transform specific genes• Less time needed to get

desired effects

Figure 14.12 Genetic engineering and traditional breedingGenetic engineering can fast-track crop development that can take years with traditional breeding practices.

GM foods: Pros and Cons

Benefits1. Enhanced plant growth2. _________ pesticide and

fertilizer use3. Enhanced ___________

composition4. Enhanced _____________

Risks• Potential for new ________• Herbicide-resistant weeds• Loss of ________________

– Biggest con of unmonitored GM crops

Genetically Modified Foods

• Regulation– FDA oversees genetically modified foods– Label requirements if food is significantly different

• Examples: – Changes in nutritional properties– Presence of allergen that consumers would not expect in the

food– Any property that would require special handling, storage,

cooking, or preservations.