Chapter 18: Food Safety: Sources of Contamination

the state of being impure or unfit for use due to the introduction of unwholesome or undesirable elements

when something not normally found in the food is added

Physical, chemical and microbial

• nonliving substances that become part of a food mixture

- metal filings, broken glass, rodent droppings, insects, and packaging materials

– create health hazards

– occur at any point in food growth or production

• Pesticide residue left on food can enter the food supply

* Toxic substances that may get into water supplies include (mercury, lead, chloroform, benzene)

• USDA and CFIA

- Conducts tests to determine if residues pose a health hazard

change in food that makes it unfit or undesirable for consumption

Microbes and enzymes

cause most cases of foodborne illness, which involves nausea, stomach cramps, vomiting, diarrhea

2 or more people becoming ill from eating the same food

By intoxication (may or may not eat the pathogen, pathogen in food produces toxins) or by infection
- Intoxication onset is much faster than infection

foodborne illness caused by a toxin released by microbes

metabolic by-products released by microbes that are harmful to humans

Killing the microbe is not enough to make food safe since the toxin must also be denatured

Bacteria (do not grow at low temperature), viruses and parasites (not microorganisms, they cause food spoilage)

Children, elderly, immuno-compromised because the

Botulism

Gram Positive: thick cell wall

Gram Negative: thin cell wall

• Gram positive

• Facultative

• Halophilic: better to survive in salts (because gram +, thick cell wall)

By a heat-resistant toxin

– is best prevented by proper hygiene, and work habits of food handlers
– can be prevented by cleaning and sanitizing food equipment

Anaerobic, only grow in the absence of oxygen

• called botulism, a progressive paralysis that
  can cause death by suffocation (stops electrical impulses, paralyses the nerve cells)
  – also causes blurred vision and a red, sore mouth, tongue, and throat

honey and improperly processed home- canned goods

• No, since it produces spores that withstand temperatures above the boiling

• Use a pressure cooker to heat even higher

Honey

| - C. botulinum is an intoxication in adults BUT it is an infection for infants

• foodborne illness that occurs when microbes release digestive enzymes that damage body tissue and cause illness

• Bacteria, parasites, viruses (70%)

• Gram-negative, rod-shaped bacteria

| - Live in the intestines of mammals

• is often due to food contaminated by exposure to raw fecal matte

• Infected food handlers and contaminated water transport E. coli to the food supply

prevented by chlorinating water supplies, washing hands after using the bathroom, and cooking meat thoroughly

• If meat is cooked thoroughly, even if it is contaminated, WON'T get you sick

diarrhea, nausea, fever, cramps, weakness, aches, and vomiting, KIDNEY disease, and even death in small children and adults

• Most won't make you sick, but there are 7 strains that cause foodborne illness

• E. col 0157:H7

Rod-shaped, aerobic, gram-positive bacterium

At refrigeration temperatures, in 10% salt solutions, and at pH of 9

– include symptoms of fever, headache, nausea, diarrhea, and vomiting

• can cause miscarriage, stillbirth, and death

• It affects the least amount of people/year, we care because the mortality rate is HIGH (20%-40%)

• High-risk populations - pregnant women, newborns, people with weakened immune systems

soft cheeses, uncooked meats, vegetables, unpasteurized milk

rod-shaped, gram-negative, anaerobic bacteria

Salmonellosis

diarrhea, cramps, fever, nausea, vomiting, chills, and headache

found in eggs, poultry, meat, and dairy products

Prevention includes keeping work surfaces and hands clean, and thoroughly cooking food

parasites, organisms that live in and feed on a host

– contaminated water
– raw fish and unwashed fruits and vegetables
– Swine, cattle, and wild animals

roundworm that occurs in hogs and wild game

– Worms attach to intestinal walls and produce new larvae that travel in the bloodstream to muscle tissue

• Trichinosis

When meat is adequately cooked, cured, smoked or fermented

microscopic disease-causing agent made of genetic material surrounded by a protein coating called a capsid

Viruses do not multiply in food, but can be transmitted in food

Viruses

| parasites don't cause a lot - 3%

Must attach to a host cell to multiply

| Unlike bacteria, which can multiply in the environment

glass, stainless steel, tile, low-moisture food, and in ground meat

1) Failing to wash hands after using the bathroom

| 2) Using sewage-contaminated water or fertilizer on food crops

– Rotavirus, Noroviruses, Hepatitis A virus

• By animals when animal feces comes in contact with food (meat or vegetables) or microorganisms are transferred during slaughter or meat packaging

• Due to time and temperature abuse: involves holding perishable food beyond 2-4 hours at temperatures not cold or hot enough

• Due to poor personal hygiene

• Due to cross contamination (food comes into contact)

Pathogen transmission due to time and temperature abuse

in the temperature danger zone

| 5 –57 C or 41 – 135 F

Food safety system used by food producers

• examines every point in the process where contamination can occur

• to remove hazards

• Reduces producer's risk of liability