Food Service Micro-Organisms

E. Coli
Listeria
Salmonella
Staph

E. Coli

Generic Escherichia coli (E. coli) bacteria are an essential, but normally harmless, component of the digestive tract of healthy animals and humans. E. coli 0157:H7, or pathogenic E. coli, is typically found in raw or undercooked ground beef. It has also been linked to infections involving vegetables, unpasteurized apple cider, raw milk, salami, alfalfa sprouts and drinking water. Upon inspection, E. coli 0157:H7 can cause hemorrhagic colitis, which is characterized by initial abdominal pain and cramping, usually followed by bloody diarrhea. Those most susceptible to severe illness include the elderly, the young and those with compromised immune systems.

E. coli is a non-spore forming, gram-negative rod.

Several disinfectants and sanitizers are known to be effective against E. coli. These products include: quats, iodophors and hypochlorite (bleach).

Listeria

Listeria monocytogenes

There are seven species of Listeria, with Listeria monocytogenes being the species of public health concern. Listeria monocytogenes has been detected in various areas of the environment, including the soil, ditches, surface water of canals, lakes and sewage. Growth of Listeria monocytogenes in the environment in food-processing plants is often found in areas where high humidity and nutrients are present (factors that are favorable to growth) such as floor drains, floors, food-processing equipment and in and around coolers.

Many food products have been associated with Listeria monocytogenes contamination, including raw milk and cheeses; fresh vegetables such as cucumbers, potatoes and radishes; ready-to-eat meat products such as beef, ham and sausage; and raw and ready-to-eat seafood and fish products. Animal carcasses are also very often associated with Listeria monocytogenes contamination. Listeria also has the ability to survive and grow in refrigerated conditions.

Infection with Listeria (called listeriosis) is characterized by a variety of severe symptoms and often leads to meningitis and meninigoencephalitis. In pregnant women in their third trimester, the consequences for the fetus include spontaneous abortion, fetal death and meningitis, while the mother may be asymptomatic or exhibit flu-like symptoms.

Listeria monocytogenes is a non-spore forming, gram-positive rod.

Several disinfectants and sanitizers are known to be effective against Listeria monocytogenes. These products include: quats, iodophors and hypochlorite.

Salmonella

Salmonella is a naturally-occurring organism that is present throughout our environment. It lives in the intestinal tracts of humans and many animals, including birds. There are several species of Salmonella that are of public health concern, including Salmonella enteritidis and Salmonella typhimurium. Many food products have been associated with Salmonella infection including raw or lightly cooked eggs or egg-containing products; mayonnaise; fruits and vegetables and some meat products. The ability of Salmonella to persist for long periods of time in foods stored at freezer and room temperatures makes it an organism of particular concern.

Salmonella is also a major problem in animal feeds and for crops fertilized with untreated sludge or sewage that is potentially contaminated with the Salmonella bacterium.

Infection with Salmonella can lead to several different conditions depending on the causative agent. Human infections can range from enteric (typhoid) fever, enterocolitis, and septicemia to aseptic reactive arthritis. Symptoms usually resolve themselves in 5-7 days and do not normally require treatment unless the patient becomes severely dehydrated or the infection spreads to the intestines.

Salmonella species are non-spore forming, gram-negative rods.

Quats, iodophors, and hypochlorite disinfectants and sanitizers have been shown to be effective against Salmonella typhimurium.

Staph

Staphylococcus aureus

There are several species of Staphylococcus, with Staphylococcus aureus being the species most associated with food-borne illnesses. Though often not reported, Staph accounts for about 14% of the total food-borne disease outbreaks within the United States.

Humans are a primary source of Staph contamination of food during preparation. Staph may also be introduced into food from food-processing equipment such as knives, meat grinders, cutting blocks and saws. Several conditions have often been associated with Staph aureus food poisoning including: inadequate refrigeration; inadequate cooking of food; poor personal hygiene (improper washing of hands and/or equipment); preparation of foods too far in advance; and extended use of warming plates for food being served. Staph can multiply rapidly in food held at room temperature and toxins can be produced. This toxin, or enterotoxin, causes gastroenteritis (flu-like symptoms). Though Staph is destroyed by thorough cooking, the toxin it produces is very resistant to heat, refrigeration and freezing.

Animals are also very important sources of Staph aureus, which are often very heavily colonized with the bacterium. Staphylococcus aureus is often the causative agent of the very serious disease, bovine mastitis.

Vomiting, diarrhea, headache and abdominal cramping usually characterize infection with Staph aureus. Symptoms generally resolve themselves in a few days.

Staph aureus is a non-spore forming, gram-positive cocci.

Quats, iodophors, and hypochlorite disinfectants and sanitizers have been shown to be effective against Staph aureus.