Food Safety Facts
A Fact Sheet for People Who Prepare Food

University of Maine Cooperative Extension
Bulletin #2258

Salmonella and Food Safety: Questions and Answers
By Mahmoud El-Begearmi, Extension specialist, nutrition and food safety

Salmonella is the most frequently reported cause of foodborne illness. In 1996, the Centers for Disease Control and Prevention (CDC) documented 39,027 cases nationwide. Much is being learned about Salmonella and the risks associated with it through FoodNet, the Foodborne Diseases Active Surveillance Network. Begun in 1995, FoodNet is a collaborative project of the U.S. Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS), CDC, the Food and Drug Administration (FDA), and seven participating states. FoodNet tracks cases of foodborne illness to better gauge the prevalence of food-related illness in this country and to monitor the effectiveness of food safety programs in reducing foodborne illness.

It is important to remember that many food products may contain bacteria. A comprehensive farm-to-table approach to food safety is necessary. Farmers, industry, food inspectors, retailers, food service workers and consumers are each critical links in the food safety chain. This fact sheet answers common questions about Salmonella, describes how USDA is addressing the problems of Salmonella contamination, and offers guidelines for safe food handling to prevent bacteria, such as Salmonella, from causing illness.

What Is Salmonella?

Salmonellosis is one of the most common bacterial foodborne illnesses, but many cases could be prevented by proper food handling practices.

The Salmonella family includes over 2,300 serotypes of bacteria, which are one-celled organisms too small to be seen without a microscope. Two types, Salmonella Enteritidis and Salmonella Typhimurium, account for approximately half of all human infections. Strains that cause no symptoms in animals can make people sick, and vice versa. If present in food, the bacteria do not affect the taste, smell or appearance of the food. They live in the intestinal tracts of infected animals and humans. 

Salmonella bacteria have been known to cause illness for over 100 years. They were discovered by an American scientist, Dr. Daniel E. Salmon.

What Is Salmonellosis?

Salmonellosis, or a Salmonella infection, is the illness that can occur if live Salmonella bacteria enter the body, usually through eating foods containing the bacteria. Salmonellosis is one of the most common bacterial foodborne illnesses, but many cases could be prevented by proper food handling practices.

How Do Salmonella Bacteria on Food Make People Sick?

Symptoms of Salmonellosis: - diarrhea - abdominal cramps - fever - chills - headache - nausea - vomiting

Bacteria can grow on just about any food, such as meat, poultry, seafood, eggs and dairy products (in particular), as well as vegetables and fruits, such as beans, grains, orange juice, cantaloupe and sprouts. To survive and multiply, bacteria need time and the right conditions: food, moisture and warm temperatures. The ideal temperature for bacterial growth is between 40 and 140 degrees F. 

Salmonella present on raw chicken can survive if the chicken is not cooked thoroughly. Salmonella can also cause foodborne illness through cross-contamination. For example, juices from raw meat or poultry prepared on a cutting board could contaminate salad ingredients if the board was not washed before cutting up the salad ingredients. If the contaminated salad sat at room temperature for any length of time, the Salmonella would multiply to dangerous numbers. The person who eats the salad then also eats the bacteria and becomes ill.

What Are the Symptoms of Salmonellosis?

According to CDC, most people experience diarrhea, abdominal cramps and fever within eight to 72 hours after the contaminated food was eaten. Additional symptoms may be chills, headache, nausea and vomiting. Symptoms may last up to seven days. Many people ill with salmonellosis recover without treatment and may never see a doctor. However, Salmonella infections can be life-threatening, especially for the very young, the elderly, and for persons with impaired immune systems.

Are There Long-Term Consequences to Salmonellosis?

Any raw food of animal origin, such as meat, poultry, milk and dairy products, eggs, seafood, and some fruits and vegetables, may carry Salmonella bacteria.

Persons with diarrhea usually recover completely, although it may be several months before their bowel habits are entirely normal. A small number of persons who are infected with Salmonella will develop pains in their joints, irritation of the eyes and painful urination. This is called Reiter’s syndrome. It can last for months or years and can lead to chronic arthritis that is difficult to treat.

How Many People Get Sick from Salmonellosis?

Not all cases of foodborne illness are reported, but experts believe that anywhere from 696,000 to 3.8 million people contract salmonellosis each year. The only way to confirm salmonellosis is to conduct laboratory tests on the stools of the ill person, a process that takes several days. To overcome the difficulties caused by unreported cases, the collaborating FoodNet sites have set up a system to actively identify laboratory-confirmed cases of foodborne illnesses. This system will provide more specific numbers in the future.

What Foods Are Most Likely to Make People Sick?

The key to preventing illness, at home, in a restaurant, at a church picnic or elsewhere, is to prevent the bacteria from growing to high levels and to destroy the bacteria through thorough cooking.

Any raw food of animal origin, such as meat, poultry, milk and dairy products, eggs, seafood, and some fruits and vegetables, may carry Salmonella bacteria. The bacteria can survive to cause illness if these foods are not thoroughly cooked. The bacteria can also cause illness if they contaminate any other food that comes in contact with the raw food. Safe food handling practices are necessary to prevent bacteria on raw food from causing illness.

Are Kosher or “Free-Range” Chickens Lower in Salmonella Bacteria?

FSIS does not know of any valid scientific information that shows that any specific type of chicken has more or less Salmonella bacteria than other poultry.

What Is the USDA Doing to Prevent Salmonella Contamination?

Under USDA’s new science-based inspection system, FSIS will test meat and poultry samples to identify pathogens, including Salmonella. For the first time ever, FSIS is requiring all processing plants to reduce bacteria by means of a Hazard Analysis and Critical Control Point (HACCP) plan and accompanying testing and performance standards. These national performance standards will be adjusted downward over time, even further reducing bacteria levels.

How Can Salmonellosis Be Prevented?

For more information about food safety, call USDA's Meat and Poultry Hotline:           1-800-535-4555

Bacteria on raw foods of animal origin do not have to cause illness. The key to preventing illness, at home, in a restaurant, at a church picnic or anywhere, is to prevent the bacteria from growing to high levels and to destroy the bacteria through thorough cooking. Follow these guidelines for safe food preparation:

Clean:
Wash Hands and Surfaces Often

• Wash your hands with hot soapy water before handling food and after using the bathroom, changing diapers and handling pets.
• Wash your cutting boards, dishes, utensils and counter tops with hot, soapy water after preparing each food item and before you go on to the next food. Sanitize with a chlorine and water solution (1 tablespoon of chlorine to 1 gallon of water).
• Use plastic or other non-porous cutting boards. These boards should be run through the dishwasher—or washed in hot, soapy water—after use.
• Consider using paper towels to clean up kitchen surfaces. If you use cloth towels, wash them often in the hot cycle of your washing machine.

Separate: 
Don’t Cross-Contaminate

• Separate raw meat, poultry and seafood from other foods in your grocery shopping cart and in your refrigerator.
• If possible, use a different cutting board for raw meat products.
• Always wash hands, cutting boards, dishes and utensils with hot, soapy water after they come in contact with raw meat, poultry and seafood.
• Never place cooked food on a plate that held raw meat, poultry and seafood.

Cook: 
Cook to Proper Temperatures

• Use a clean thermometer, which measures the internal temperature of cooked foods, to make sure meat, poultry, casseroles and other foods are cooked all the way through.
• Cook roasts and steaks to at least 145 degrees F. Poultry parts should be cooked to 170 degrees F and whole poultry to 180 degrees F for doneness.
• Cook ground beef, where bacteria can spread during processing, to at least 160 degrees F.
• Cook eggs until the yolk and white are firm. Don’t use recipes in which eggs remain raw or are only partially cooked.
• Fish should be opaque (not clear) and flake easily with a fork.
• When cooking in a microwave oven, make sure there are no cold spots in food where bacteria can survive. For best results, cover food, stir and rotate for even cooking. If there is no turntable, rotate the dish by hand once or twice during cooking.
• Bring sauces, soups, and gravy to a boil when reheating. Heat other leftovers thoroughly to at least 165 degrees F (steaming hot).

Chill: 
Refrigerate Promptly

• Refrigerate or freeze perishables, prepared foods and leftovers within two hours or sooner.
• Never defrost food at room temperature. Thaw food in the refrigerator, under cold running water or in the microwave. Marinate foods in the refrigerator.
• Divide large amounts of leftovers into small, shallow containers for quick cooling in the refrigerator.
• Don’t pack the refrigerator. Cool air must circulate to keep food safe. 

This publication was revised and reprinted from “Salmonella Questions and Answers,” a backgrounder publication produced by the FSIS, USDA in February, 1998.

For more information about food safety, call USDA's Meat and Poultry Hotline at 1-800-535-4555 or contact your University of Maine Cooperative Extension county office.

Published and distributed in furtherance of Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.

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