Chapter 18: Food Safety: Sources of Contamination Flashcards
What is contamination?
the state of being impure or unfit for use due to the introduction of unwholesome or undesirable elements
When does contamination occur?
when something not normally found in the food is added
What are the 3 types of food contamination?
Physical, chemical and microbial
What are physical contaminants? Name some examples.
- nonliving substances that become part of a food mixture
- metal filings, broken glass, rodent droppings, insects, and packaging materials
What are the consequences of physical contaminants? When can they occur?
– create health hazards
– occur at any point in food growth or production
Name 2 sources of chemical contaminants.
- Pesticide residue left on food can enter the food supply
* Toxic substances that may get into water supplies include (mercury, lead, chloroform, benzene)
Who monitors pesticides? What do they do?
- USDA and CFIA
- Conducts tests to determine if residues pose a health hazard
What is food spoilage?
change in food that makes it unfit or undesirable for consumption
What often work together to cause food spoilage?
Microbes and enzymes
What do pathogens cause?
cause most cases of foodborne illness, which involves nausea, stomach cramps, vomiting, diarrhea
What is an outbreak of foodborne illnesùs?
2 or more people becoming ill from eating the same food
How do pathogens cause illness? How do they differ?
By intoxication (may or may not eat the pathogen, pathogen in food produces toxins) or by infection - Intoxication onset is much faster than infection
What is foodborne intoxication?
foodborne illness caused by a toxin released by microbes
What are toxins?
metabolic by-products released by microbes that are harmful to humans
Does getting rid of microbes protect humans from harm?
Killing the microbe is not enough to make food safe since the toxin must also be denatured
Name the 3 pathogens that cause acute food borne illness.
Bacteria (do not grow at low temperature), viruses and parasites (not microorganisms, they cause food spoilage)
Who is at higher risk for food borne illnesses?
Children, elderly, immuno-compromised because the
Give an example of intoxication.
Botulism
How does the cell wall of positive and negative gram bacterias differ?
Gram Positive: thick cell wall
Gram Negative: thin cell wall
What are the characteristics of S. aureus?
- Gram positive
- Facultative
- Halophilic: better to survive in salts (because gram +, thick cell wall)
What is food borne illness from S. aureus caused by?
By a heat-resistant toxin
How can food borne illness from S. aureus be prevented?
– is best prevented by proper hygiene, and work habits of food handlers
– can be prevented by cleaning and sanitizing food equipment
Is c. botulinum aerobic or anaerobic?
Anaerobic, only grow in the absence of oxygen
What is the food illness from C. botulinum? What does it cause?
- 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
What does C. botulinum use as a food source?
honey and improperly processed home- canned goods
Can you kill C. botulinum with heat? Why? What can you do?
- No, since it produces spores that withstand temperatures above the boiling
- Use a pressure cooker to heat even higher
What should infants up to 12 months not be fed?
Honey
- C. botulinum is an intoxication in adults BUT it is an infection for infants
What is a foodborne infection? What can it be caused by?
- foodborne illness that occurs when microbes release digestive enzymes that damage body tissue and cause illness
- Bacteria, parasites, viruses (70%)
What are the characteristics of E. coli? Where does E. coli live?
- Gram-negative, rod-shaped bacteria
- Live in the intestines of mammals
What are the main cause of E. coli foodborne illnesses?
- 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
How can we prevent E. coli contaminations?
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
What does E. coli food illness cause?
diarrhea, nausea, fever, cramps, weakness, aches, and vomiting, KIDNEY disease, and even death in small children and adults
How many E. coli types will make you sick? Which one is the main type?
- Most won’t make you sick, but there are 7 strains that cause foodborne illness
- E. col 0157:H7
What are the characteristics of L. monocytogenes?
Rod-shaped, aerobic, gram-positive bacterium
Where is L. monocytogenes able to multiply?
At refrigeration temperatures, in 10% salt solutions, and at pH of 9
What are the symptoms of food illness from L. monocytogenes?
– include symptoms of fever, headache, nausea, diarrhea, and vomiting
- can cause miscarriage, stillbirth, and death
Who does L. monocytogenes affect?
- 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
What are the food sources of L monocytogenes?
soft cheeses, uncooked meats, vegetables, unpasteurized milk
What are the characteristics of salmonella?
rod-shaped, gram-negative, anaerobic bacteria
What does salmonella cause?
Salmonellosis
What are the symptoms of salmonella?
diarrhea, cramps, fever, nausea, vomiting, chills, and headache
Whee is salmonella found?
found in eggs, poultry, meat, and dairy products
How can we prevent from salmonella?
Prevention includes keeping work surfaces and hands clean, and thoroughly cooking food
What are parasitic infections caused by?
parasites, organisms that live in and feed on a host
What are common sources of parasitic infections?
– contaminated water
– raw fish and unwashed fruits and vegetables
– Swine, cattle, and wild animals
What is trichinella spiralis? What does it occur in?
roundworm that occurs in hogs and wild game
How does trichinella spiralis infection spread? What is it called?
– Worms attach to intestinal walls and produce new larvae that travel in the bloodstream to muscle tissue
- Trichinosis
How is trichinella spiralis destroyed?
When meat is adequately cooked, cured, smoked or fermented
What is a virus? What is it made of? What is it surrounded by?
microscopic disease-causing agent made of genetic material surrounded by a protein coating called a capsid
Do viruses multiply in food?
Viruses do not multiply in food, but can be transmitted in food
What causes the most foodborne illnesses?
Viruses
parasites don’t cause a lot - 3%
How do viruses multiply?
Must attach to a host cell to multiply
Unlike bacteria, which can multiply in the environment
What can viruses survive on?
glass, stainless steel, tile, low-moisture food, and in ground meat
Name 2 ways that viral infections are transmitted by the fecal-oral route.
1) Failing to wash hands after using the bathroom
2) Using sewage-contaminated water or fertilizer on food crops
Name the 3 viruses associated with foodborne illness.
– Rotavirus, Noroviruses, Hepatitis A virus
How do pathogens enter the food supply? (2)
- 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)
What is the biggest cause of foodborne illness?
Pathogen transmission due to time and temperature abuse
Where do most pathogens multiply rapidly?
in the temperature danger zone
5 –57 C or 41 – 135 F
What is the Hazard Analysis and Critical Control Point (HACCP)?
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
