These are some tips for preventing foodborne illnesses caused by pathogens. Some of them are fatal, however, in a person with a weakened immune system all of them are potentially deadly.

Campylobacter jejuni
It reproduces in the "intestinal tracts of animals and birds, raw milk, untreated water, and sewage sludge" and is transmitted by "contaminated water, raw milk, and raw or under-cooked meat, poultry, or shellfish".

Clostridium botulinum
It is "widely distributed in nature; soil, water, on plants, and intestinal tracts of animals and fish. Improperly canned foods, garlic in oil, vacuum-packed and tightly wrapped food" are the main culprits.

Clostridium perfringens
Found in "soil, dust, sewage, and intestinal tracts of animals and humans". Also called "'the cafeteria germ' because many outbreaks result from food left for long periods in steam tables or at room temperature. Bacteria destroyed by cooking, but some toxin-producing spores may survive."

Escherichia coli 0157:H7
Found in the "intestinal tracts of some mammals, raw milk, unchlorinated water; one of several strains of E. coli than can cause human illness.
It is transmitted by "contaminated water, raw milk, raw or rare ground beef, unpasteurized apple juice or cider, uncooked fruits and vegetables; person-to-person.

Listeria monocytogenes
Found intestinal tracts of humans and animals, milk, soil, leaf vegetables, and processed foods; can grow slowly at refrigerator temperatures". Transmitted by "soft cheese, raw milk, improperly processed ice cream, raw leafy vegetables, meat, and poultry.

Salmonella (over 2300 types)
Found in the "intestinal tract and feces of animals; Salmonella enteritidis in raw shell eggs. It is transmitted through raw or undercooked eggs, poultry, and meat; raw milk and dairy products; seafood and food handlers".

Shigella (over 30 types)
Found in the "human intestinal tract; rarely found in other animals" and transmitted "person-to-person by fecal-oral route; fecal contamination of food and water. Most outbreaks result from food, especially salads, prepared and handled by workers using poor personal hygiene."

Staphylococcus aureus
Found on "humans (skin, infected cuts, pimples, noses, and throats)" and transmitted by people to food through improper food handling. Multiply rapidly at room temperature to produce a toxin that causes illness.

These are some general rules that can help you prevent foodborne contamination:

• Eat your food the freshest possible, the longer in storage the more dangerous it may be.
  
• Check expiration dates and see that the packages and cans are in good condition.
  
• "Store food in the refrigerator (40 °F or below) or freezer (0 °F or below).
  
• Cook food to 160 °F (145 °F for roasts, steaks and chops of beef, veal, and lamb).
  
• Maintain hot cooked food at 140 °F or above.
  
• When reheating cooked food, reheat to 165 °F."
  
• Wash your hands thoroughly before cooking and after handling chicken and beef.
  
• Be specially careful about hygiene, proper preparation and storage if children or people with compromised or weak inmune system will consume the food.

For more information visit the USDA Food Safety and Inspection Service website.