2. Food Safety: Sources of Contamination18
Food Safety: Sources of Contamination

3. Objectives Identify three main types of food contaminants.
Differentiate among the types of foodborne illnesses.
Name pathogens that cause foodborne illnesses.
Describe the two main ways pathogens enter the food supply.
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4. Objectives
Use food handling procedures that will help prevent the growth of illness-causing microbes.
List the seven steps in developing a HACCP system.

5. Types of Food Contamination
Contamination is the state of being impure or unfit for use due to the introduction of unwholesome or undesirable elements
It occurs when something not normally found in the food is added
The 3 types of food contamination are
physical, chemical, and microbial

6. Physical Contaminants
These are nonliving substances that become part of a food mixture such as
metal filings, broken glass, rodent droppings, insects, and packaging materials
Physical contamination can
create health hazards
occur at any point in food growth or production
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7. Physical Contaminants
Insects and rodents damage food, transfer microbes onto food, deposit their waste on food, or their body parts may be mixed into food during processing
The FDA examines food products for insect parts
©Sascha Burkard/Shutterstock.com

8. Chemical Contaminants
Pesticide residue left on food can enter the food supply
The USDA monitors pesticides and conducts tests to determine if residues pose a health hazard
Toxic substances that may get into water supplies are
mercury, cadmium, lead, chloroform, benzene, and PBCs
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9. Chemical Contaminants
Main sources of toxins in water supplies are pesticides and industrial waste
Some pesticides have been banned because they are not biodegradable
Rain can carry airborne exhausts to earth
Wastes may be dumped into bodies of water
Water filtered through dump sites can carry pollutants into the water supply
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10. Chemical Contaminants
Mercury is often found in industrial waste
This has led to the monitoring of mercury levels in fish
Lead contamination has lessened due to regulations and voluntary industry changes
Consumers still need to know that lead leaches into food from certain dishes, lead crystal glassware and decanters, and silver-plated hallowware
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11. Chemical Contaminants
Polytetrafluoroethylene (PTFE) coating on nonstick cookware is being studied for its safety
Currently it appears safe when used in normal cooking
©KKulikov/Shutterstock.com

12. Microbial Contaminants
Food spoilage is a change in food that makes it unfit or undesirable for consumption
Microbes and enzymes often work together to cause spoilage
Microorganisms can create changes in food that cause a foodborne illness

13. Types of Foodborne Illness
Pathogens in food cause most cases of foodborne illness, which involves
nausea, stomach cramps, vomiting, diarrhea
An outbreak of foodborne illness is
2 or more people becoming ill from eating the same food
Pathogens cause illness by intoxication or by infection

14. Food Intoxication
A foodborne illness caused by a toxin released by microbes is food intoxication
Toxins are metabolic by-products released by microbes that are harmful to humans
Several common microbes release toxins
Killing the microbe is not enough to make food safe since the toxin must also be damaged or altered

15. Clostridium Perfringens
Clostridium perfringens causes a frequent and mild form of food intoxication
The microbe is
gram-positive, anaerobic, and heat-resistant
widespread in air, soil, water, and sewage
often traced to high-protein foods because it raises stomach pH enough to allow acid-resistant C. perfringens to survive
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16. Clostridium Perfringens
Food illness from C. perfringens
can occur from 2 to 29 hours after eating contaminated food
includes diarrhea, bloating, and cramps
can be controlled by following sanitation procedures, and cooking and storing foods at the proper temperatures

17. Staphylococcus Aureus
Staphylococcus aureus is commonly found on humans and animals
The microbe
is gram positive, facultative, and halophilic
grows slowly when other bacteria are present
is found in red meats, poultry, potato, macaroni, and tuna salads, custards and cream-filled pastries
has a heat-resistant toxin
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18. Staphylococcus Aureus
Food illness from S. aureus
is caused by a heat-resistant toxin
can include nausea, diarrhea, vomiting, and abdominal cramps
is best prevented by monitoring the health, hygiene, and work habits of food handlers
can be prevented by cleaning and sanitizing food equipment

19. Clostridium Botulinum
Clostridium botulinum is an extremely dangerous anaerobic bacteria
The microbe
is found in all soil types and in sediments of marshes and lakes
uses honey and improperly processed home-canned goods as a food source
produces spores that withstand temperatures above the boiling for hours
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20. Clostridium Botulinum
Food illness from C. botulinum
is called botulism, a progressive paralysis that can cause death by suffocation
also causes blurred vision and a red, sore mouth, tongue, and throat
Infants up to 12 months should not be fed honey
Chemicals are added to meat products to destroy C. botulinum spores

21. Escherichia Coli
Escherichia coli are gram-negative, rod-shaped bacteria that live in the intestines of mammals
Infected food handlers and contaminated water transport E. coli to the food supply
There are 7 strains that cause foodborne illness
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22. Escherichia Coli Food illness from E. coli
include diarrhea, nausea, fever, cramps, weakness, aches, and vomiting, even death in small children and adults
is often due to food contaminated by exposure to raw fecal matter
is prevented by chlorinating water supplies, washing hands after using the bathroom, and cooking meat thoroughly

23. Food Infection
A foodborne illness that occurs when microbes release digestive enzymes that damage body tissue and cause illness is known as a food infection
It may be caused by bacteria, parasites, and viruses
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©Sebastian Kaulitzki/Shutterstock.com

24. Listeria Monocytogenes
Listeria monocytogenes is a rod-shaped, aerobic, gram-positive bacterium
The microbe is
harder to kill than many foodborne pathogens
found in soil, water, and many animals
able to multiply at refrigeration temperatures, in 10% salt solutions, and at a pH of 9
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25. Listeria Monocytogenes
Food illness from L. monocytogenes
include symptoms of fever, headache, nausea, diarrhea, and vomiting
affects high-risk populations—pregnant women, newborns, and people with weakened immune systems
can cause miscarriage, stillbirth, and death
Food sources include soft cheeses, uncooked meats, unwashed vegetables, unpasteurized milk

26. Salmonellae
Salmonellae are rod-shaped, gram-negative, anaerobic bacteria that cause salmonellosis
Symptoms include diarrhea, cramps, fever, nausea, vomiting, chills, and headache
The microbe is found in eggs, poultry, meat, and dairy products
Prevention includes keeping work surfaces and hands clean, and thoroughly cooking food

27. Parasitic Infections
Parasitic Infections are caused by parasites, organisms that live in and feed on a host
Common sources are
contaminated water
raw fish and unwashed fruits and vegetables
hogs, cattle, and wild animals

28. Trichinella Spiralis
Trichinella spiralis is a 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
Infection is called trichinosis
It is destroyed when meat is adequately cooked, cured, smoked, or fermented

29. Viral Infections
A virus is a 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
A virus must attach to a host cell to multiply
Viruses can survive on glass, stainless steel, tile, low-moisture food, and in ground meat
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30. Viral Infections
Viral infections are transmitted by the fecal-oral route in 2 ways
failing to wash hands after using the bathroom
using sewage-contaminated water or fertilizer on food crops
Poliovirus is practically eliminated, but 3 other viruses can cause foodborne illness
Rotavirus, Norwalk virus, Hepatitis

31. Rotavirus Rotavirus is a flu-like infection common in children
Symptoms include vomiting, diarrhea, and low-grade fever for up to 10 days
Prevention involves good hygiene practices
©Thomas M Perkins/Shutterstock.com

32. Norwalk Virus Norwalk virus causes a mild flu-like illness
It occurs among all age groups and only lasts up to 2 days
Outbreaks have been traced to green salads, raw oysters, cake frosting, and chicken sandwiches
Prevention involves good hygiene

33. Hepatitis
Hepatitis is a viral infection that can cause liver damage, liver failure, and even death
Hepatitis A is the only strain that can be transmitted through contaminated food
Foods at risk are uncooked salad ingredients, raw shellfish, and foods handled after cooked
Infection can be prevented by washing hands and wearing disposable gloves

34. Prions
Prion is a term for a misfolded protein that can cause infection
Prions form clumps in the central nervous system and brain tissue
Disease in cows is called bovine spongiform encephalopathy (BSE), or mad cow disease
Disease in humans is called Creutzfeldt-Jakob disease (CJD)

35. How Pathogens Enter the Food Supply
Pathogen transmission by animals occurs when
animal feces comes in contact with food or microbes are transferred during slaughter or meat packaging
parasites enter the digestive track while eating raw fish that was not handled properly
meat and dairy products are not handled properly
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36. How Pathogens Enter the Food Supply
Pathogen transmission due to time and temperature abuse
is the biggest cause of foodborne illness
involves holding perishable food beyond 2 hours at temperatures not cold or hot enough
Most pathogens multiply rapidly in the temperature danger zone (5°–57°C or 41°–135°F)
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37. How Pathogens Enter the Food Supply
Pathogen transmission due to poor personal hygiene can make food unsafe
Food handlers and customers are a major cause
Sources of contamination include hands, breath, hair, wounds, unshielded coughs and sneezes, and perspiration
Prevention includes washing hands frequently and avoiding handling food when ill
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38. How Pathogens Enter the Food Supply
Pathogen transmission due to
cross-contamination
– occurs when food comes in contact with a contaminated surface during harvest, storage, preparation, or holding
– is prevented by thoroughly washing cutting boards, knives, and hands after preparing raw foods
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39. How Pathogens Enter the Food Supply
Pathogen transmission due to improper handling procedures by uninformed or careless consumers
is the root cause of all foodborne illness
Pathogens make people ill long before the food shows signs of spoilage
Any food improperly handled can cause foodborne illness

40. Food Industry Sanitation Procedures
Monitoring the safety of the food supply involves
voluntary effort by the food industry to set and follow standards to prevent contamination
government regulation and inspection of food processing plants and their safety-related record keeping

41. Developing a HACCP System
HACCP (Hazard Analysis and Critical Control Point) is a food safety system used by food producers
It examines every point in the process where contamination can occur
A critical control point is any step where hazards can be removed, prevented, or minimized
Hazards are anything that can cause harm
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42. Developing a HACCP System
Documentation of monitoring and correction at each critical control point is key
HACCP reduces a food producer’s risk of liability and prevents outbreaks of foodborne illness
These accomplishments can also increase profits
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43. Seven Principles of HACCP
Conduct a hazard analysis
Identify critical control points
Establish critical limits
Establish monitoring procedures
Establish corrective actions
Establish verification procedures
Establish record-keeping and documentation procedures

44. Government Regulation of the Food Industry
The FDA and USDA monitor the safety of the food supply by
setting standards such as cooking and cooling temperatures
regulating food shipped across state lines
Local and state health departments
monitor foods produced and sold within states and regulate foodservice operations
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45. Government Regulation of the Food Industry
A food business must get a permit and be inspected to ensure safety and sanitation regulations are being followed before opening
At least one supervising employee must be a certified food protection manager
Violations of regulations results in warning, fines, or even closure of the establishment

46. Recap Food contaminants can be
physical
chemical
microbial
Pathogens can cause foodborne illness through intoxication or infection
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47. Recap Pathogens enter the food supply by
being transmitted by animals
improper food handling procedures
A HACCP system examines every point in food production where contamination can occur and follows 7 principles to prevent contamination