Food Poisoning Background

What do microorganisms need to survive, grow, and reproduce?

• available water
• appropriate pH
• optimal temperature
• time to grow
• nutrients
• oxygen

The optimum conditions for growth in food are: high protein, low acidity, moist foods. Different organisms, however, can survive in a variety of environments with varying conditions.

Organisms that produce spores can survive cooking at high temperatures. Re-heating causes heat shock, which causes the spores to germinate. If given the right conditions, such as holding in the temperature danger zone of 4°C-60°C for too long, the spores can start to grow and replicate, and can cause illness.

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Which microorganisms are of concern?

1. Staphylococcus aureus

FOUND IN:

• nose and on skin of humans

HOW IT GETS INTO FOOD:

• infected food handlers

FOODS ITS COMMONLY ASSOCIATED WITH:

• foods that are frequently handled during preparation (ex. breads, pastries, meats)
• ready to eat foods (ex. vegetables, fruit, sandwiches)
• salty foods like ham, and bacon
• high protein foods (ex. meats)

OTHER IMPORTANT INFORMATION:

• toxin produced by some types is not destroyed by cooking, and so remains on food

2. Clostridium botulinum (Type E) 

FOUND IN:

• naturally in soils and sediments of streams, lakes, and coastal waters
• intestinal tract and feces of animals and fish
• gills and viscera of other crabs and shellfish

HOW IT GETS INTO FOOD:

• C. botulinum (Type E) produces spores that are heat-resistant, which enhances its survival 
• needs an oxygen free environment to grow, reproduce, and produce toxins
• food mishandling
• inadequate processing

FOODS ITS COMMONLY ASSOCIATED WITH:

• homecanned and fermented foods (vegetables like peppers & pimentos, seafood, meats)
• honey
• other food environments that are oxygen-free (ex. garlic in oil)
• some commercially processed foods (ex. sausages, canned vegetables, seafood products)

OTHER IMPORTANT INFORMATION:

•  the toxin produced by this microorganism is destroyed from cooking at high temperatures
• this microorganism is a spore-former

3. Salmonella serovars (Typhimurium and Paratyphimurium)

FOUND IN:

• intestinal tract and feces of animals and humans

HOW IT GETS INTO FOOD:

• food mishandling by an infected or contaminated food handler via the fecal-oral route

FOODS ITS COMMONLY ASSOCIATED WITH:

• meats
• milk
• eggs

4. Escherichia coli O157:H7

FOUND IN:

• intestinal tracts and feces of animals and humans

HOW IT GETS INTO FOOD:

• food mishandling by an infected or contaminated food handler via the fecal-oral route

FOODS ITS COMMONLY ASSOCIATED WITH:

• raw unpasteurized milk
• water
• vegetables
• ground beef

5. Clostridium perfringens

FOUND IN:

• decaying vegetation
• marine sediments
• intestinal tract and feces of humans, animals, and insects
• soil

HOW IT GETS INTO FOOD:

• food mishandling by an infected or contaminated food handler via the fecal-oral route
• this microorganism produces spores that are heat-resistant to enhance its survival

FOODS ITS COMMONLY ASSOCIATED WITH:

• meat products

OTHER IMPORTANT INFORMATION:

• this microorganism is a spore-former

6. Yersinia enterocolitica

FOUND IN:

• intestines and feces of animals (ex. cattle, deer, pigs, and birds)

HOW IT GETS INTO FOOD:

• infected animals
• food mishandling by an infected or contaminated food handler via the fecal-oral route
• this microorganism is can survive at very low temperatures (4°C), and so can grow and replicate in food stored in the refrigerator

FOODS ITS COMMONLY ASSOCIATED WITH:

• pork products
• contaminated or unpasteurized milk
• untreated water

7. Listeria monocytogenes

FOUND IN:

• intestinal tract and feces of humans and animals (ex. sheep, cattle)
• soil
• vegetation
• water

HOW IT GETS INTO FOOD:

• food mishandling by an infected or contaminated food handler via the fecal-oral route
• microorganism is capable of surviving at very low temperatures (0°C-4°C), and so can grow and replicate in food stored in the refrigerator

FOODS ITS COMMONLY ASSOCIATED WITH:

• raw unpasteurized milk
• dairy
• softened/ripened cheese (ex. brie, feta)
• raw vegetables
• fermented raw-meat sausages
• raw and cooked poultry
• raw meats of all types
• raw and smoked fish

Listeria is more likely to cause death than other bacteria that cause food poisoning. In fact, 20 to 30 percent of foodborne listeriosis infections in high-risk individuals may be fatal. However, it should be noted that listeriosis is a relatively rare disease in Canada.

Canadian Food Inspection Agency

http://www.inspection.gc.ca/english/fssa/concen/cause/listeriae.shtml

8. Campylobacter jejuni

FOUND IN:

• intestinal tract and feces of animals

HOW IT GETS INTO FOOD:

• food mishandling by an infected or contaminated food handler via the fecal-oral route

FOODS ITS COMMONLY ASSOCIATED WITH:

• raw unpasteurized milk
• drinking water
• incorrectly prepared meat (pork)
• poultry

9. Giardia lambia

FOUND IN:

• intestinal tract and feces of humans and animals

HOW IT GETS INTO FOOD:

• food mishandling by an infected or contaminated food handler via the fecal-oral route

FOODS ITS COMMONLY ASSOCIATED WITH:

• water

OTHER IMPORTANT INFORMATION

• this is a parasite that produces infective and resistant oocysts
• can be killed by boiling water or use chlorine to disinfect water

10. Shigella spp.

FOUND IN:

• intestinal tract and feces of humans 

HOW IT GETS INTO FOOD:

•  food mishandling by an infected or contaminated food handler via the fecal-oral route
•  pests such as cockroaches and flies that are contaminated (ex. from walking in garbage)

FOODS ITS COMMONLY ASSOCIATED WITH:

• water

After reading about these microorganisms, I'm sure you noticed that many of them get into food through the fecal-oral route. This route of transmission is easily avoided by making sure that you wash your hands properly after going to the bathroom and before preparing food.

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What are the different types of contamination?

• Chemical: pesticides and herbicides
• Microbial: bacteria, fungus, parasites, protozoa, mould
• Physical: feces, hair, insects, glass, pests (rodents)

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What is considered a potentially hazardous food?

A potentially hazardous food supports the growth of microorganisms that have the potential to cause illness. Generally foods that have a pH of 4.6-8.5, and available water (above 0.85) are potentially hazardous. This includes raw or cooked meats, foods of plant origin that is heat-treated or consists of raw seed sprouts, cut melons, and garlic and oil mixtures.

Some examples of potentially hazardous foods in a bed and breakfast setting are:

• vegetables (heat treated or cooked)

• coffee creamers

• fresh or cooked eggs (not boiled)

• meat (sausage, chicken, ham)

• cheese

• cream filled pastries

• soy milk

• milk

• yogurt

• cooked/fried onions

• potatoes

• raw melon slices (cantaloupe)

• seafood

• hollandaise sauce

Fresh fruits and vegetables are not considered potentially hazardous as long as from an approved source, and therefore cleaned properly. Instead, fruits and vegetables would be considered to be hazardous as a vehicle for transmission from improper sanitation in combination with an infected food handler, or contamination from processing or mishandling (as they are ready-to-eat foods after preparation, so there is no kill step).

Bread is also not considered a potentially hazardous food but can grow mould like Aspergillus (common bread mold). This mold is generally just a spoilage organism though and isn’t necessarily a health concern.

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What is considered a poisonous food?

1. Mushrooms

There are many mushrooms that grow in nature that are poisonous, and there is no clear way to identify poisonous from non-poisonous mushrooms. For example, the extremely poisonous jack-o-lantern mushroom is often mistaken for the common non-poisonous chanterelle mushroom.

For the safety of your guests, make sure you get your mushrooms from an approved source and don't pick them yourself.

2. Seafood (Shellfish)

Paralytic shellfish poisoning (PSP) can occur during red tide. Red tide is an algal bloom in sea waters. Shellfish are a particular concern as they are filter feeders and they take in the sea water (containing algae). The toxin that the algae produces is accumulated in the shellfish. When these contaminated shellfish are consumed, they can cause paralysis due to the PSP.

For the safety of your guests, buy your seafood from an approved source and do not obtain the seafood yourself from the beach (ex. clam digging).

For more information regarding PSP, visit the BCCDC website.


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Contributing Factors

Some contributing factors that allow for the contamination, survival, growth, and reproduction of potentially hazardous microorganisms include:

• poor personal hygiene (ex. improper hand washing)
• temperature and time abuse (ex: held in temperature danger zone 4°C – 60 °C)
• un-approved sources
• improper sanitation of equipment, utensils, and food-contact surfaces
• contaminated food (ex. raw meat coming into contact with cooked food)

How This Applies to Your Bed and Breakfast

• Be aware of potentially hazardous foods

• Many harmful microorganisms that cause food borne illness’s are associated with infected food handlers or infected animals and are spread via fecal-oral contamination. THEREFORE IT IS IMPORTANT TO WASH YOUR HANDS, SANITIZE PROPERLY, AND OBTAIN FOOD FROM APPROVED SOURCES AT ALL TIMES!

• Contamination does not just involve microorganisms. Contamination also involves: chemicals, parasites, insects, hair, etc…. so beware.

POP QUIZ:

Food Poisoning Background » Quiz School

References:

Picture 1: http://www.rosemerena.org/home/wp-content/uploads/2009/04/greening8.jpg
Picture 2: http://oryana.coop/blog/wp-content/uploads/2010/03/eggs-main_Full1.jpg
Picture 3: http://www.quitsmokingonline.com/quitsmokingnatural/images/glass-of-water.jpg
Picture 4: http://thisisjack.files.wordpress.com/2009/11/andoullie20sausage20raw.jpg
Picture 5: http://www.mushroomthejournal.com/mhma/images/favorites/lateritius.jpg


Heymann, David L. (2008). Control of Communicable Diseases Manual, 19th Edition. American Public Health Association, Washington.

International Association for Food Protection. (1999). Procedures to Investigate Foodborne Illness, 5th Edition. Iowa.