Salmonella

Salmonella are usually motile, non-sporeforming, and Gram-negative rod-shaped bacteria. They are widespread in the environment and are associated with all animal species including mammals, birds, reptiles, and amphibians. Salmonella have been found in water, soil, insects, on factory and kitchen surfaces, animal feces, raw meats, poultry, and seafood. While these are common sources, Salmonella have been isolated from numerous other food sources.

Symptoms of Salmonellosis

Acute symptoms may include nausea, vomiting, abdominal cramps, diarrhea, fever, and headache. Symptoms typically develop 12 to 72 hours after ingestion of contaminated food. Most infected persons recover without treatment after four to seven days. As with many food-borne pathogens, young children, the elderly, and the immunocompromised are the most common victims of serious Salmonella infections. Depending on host factors such as age and health, the infective dose has been estimated to be as low as 15 to 20 cells for some strains.

In a small percentage of cases, persons infected with Salmonella can develop chronic, long-term problems. Reactive arthritis may begin three to four weeks after onset of acute symptoms, and the arthritic symptoms can be debilitating and last for six months or more.

Those at Risk

All age groups are susceptible to infections, but salmonellosis has a more severe effect on elderly, young, and sick people. The frequency of salmonellosis in AIDS patients is estimated to be 20 times higher than the general population. School lunch programs, nursing homes, and hospitals often require food from sources with more rigorous quality assurance programs in place; these programs might include increased sanitation, stricter rules governing personal hygiene, and/or increased microbial testing of finished products.

Foods Associated with Salmonella

Salmonellosis outbreaks have occurred from a variety of foods including poultry, meats, eggs, milk products, fruit juice, fish, shrimp, frog legs, yeast, coconut, sauces and salad dressings, cake mixes, breakfast cereal, cream-filled desserts and toppings, dried gelatin, peanut butter, cocoa, chocolate, and dried spices.

The incidence of Salmonella is much higher in raw agricultural products (e.g. raw eggs, or uncooked poultry or meat) than in cooked or processed food products. However, Salmonella can occur in other foods as a result of cross-contamination with raw foods or from contamination from humans, animals, birds, or reptiles. Additionally, because of the microorganism’s ability to survive in a wide range of environments, Salmonella has been found in dry and dehydrated foods (e.g. cocoa, chocolate, dry milk, spices, and cereal products) and in higher-acid food products (e.g. non-pasteurized orange juice). Thus, preventative measures are extremely important at all food handling and processing steps.

Additional Resources

www.cdc.gov/salmonella/ [1]

www.salmonella.org [2]

www.dupagehealth.org/safefood/industry/fs/hw.asp [3]

www.cfsan.fda.gov/~dms/foodcode.html [4]