Chapter Images shutterstock.com Food Safety: Sources of Contamination 18.

Chapter

Images shutterstock.com

Food Safety:Sources of

Contamination

18

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.

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.

Objectives

continued


Objectives

• Use food handling procedures that will help prevent the growth of illness-causing microbes.

• List the seven steps in developing a HACCP system.

Objectives


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


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

productioncontinued


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


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

continued



• 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 supplycontinued



• 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

continued



• Polytetrafluoroethylene (PTFE) coating on nonstick cookware is being studied for its safety– Currently it appears safe when used in

normal cooking

©KKulikov/Shutterstock.com


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


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


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


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

continued


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


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 toxincontinued


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


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

continued


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


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

continued


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


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

continued©Sebastian Kaulitzki/Shutterstock.com


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

continued


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


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


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


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


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 continued


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


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


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


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


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)


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

continued


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)

continued


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 continued


How Pathogens Enter the Food Supply

• Pathogen transmission due tocross-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

continued


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


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


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

continued


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

continued


Seven Principles of HACCP

1. Conduct a hazard analysis2. Identify critical control points3. Establish critical limits4. Establish monitoring procedures5. Establish corrective actions6. Establish verification procedures7. Establish record-keeping and

documentation procedures


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

continued


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


• Food contaminants can be– physical– chemical– microbial

• Pathogens can cause foodborne illness through intoxication or infection

Recap

continued


• 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

Recap

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