Ongoing Outbreak from An Unusual Salmonella

A salmonellosis outbreak in 34 states appears to be linked to specific types of raw red tomatoes - primarily plum, Roma, or round red - and the products containing them. The bacteria causing the illnesses are an uncommon type of Salmonella called Salmonella Saintpaul.

Since mid-April, there have been more than 700 confirmed cases of illness caused by infection with Salmonella Saintpaul. Because of delays in reporting and because many people who become ill don't have a stool sample tested, it's probable that many more illnesses have occurred than the numbers that have been officially reported.

During the same period in 2007, only 3 people infected with this strain of Salmonella Saintpaul were identified.

The US Food and Drug Administration (FDA) is advising consumers to eat only tomatoes that have not been associated with the outbreak. Because raw tomatoes are often used in fresh salsa, guacamole, pico de gallo, and other dishes, it's best to stay away from these foods for now unless you're sure they don't contain any of the tomato types mentioned.

Restaurants, grocery stores, and food service operators have been advised by the FDA not to provide raw red plum, Roma, or red tomatoes and products made from them unless they are from one of the areas listed on its website.

If you've recently bought one of these types of tomatoes and still have them, either contact the store where you bought them to see where the tomatoes came from, or throw them away.

Cherry tomatoes, grape tomatoes, and tomatoes sold with the vine still attached, from any source, are still considered safe to eat.

Human Infection with Salmonella
Salmonella is actually a group of bacteria that can cause diarrheal illness in humans. Salmonella (named after a scientist named Salmon, who discovered them) live in the intestinal tracts of people and other animals. The bacteria spread when people eat food contaminated with animal feces or contaminated by people who don't wash their hands after handling the food or using the bathroom.

Although tomatoes are the source of the current Salmonella outbreak, contamination is more typically from raw foods of animal origin, such as beef, poultry, milk, or eggs. Contaminated foods usually look and smell normal. Thorough cooking kills Salmonella.

Salmonella can also be found in the feces of some pets, especially those with diarrhea, and people can become infected if they do not wash their hands after contact with the feces. Reptiles are particularly likely to harbor Salmonella and people should always wash their hands immediately after handling a reptile, even if the animal is healthy. Adults should make sure that children wash their hands after handling a reptile.

Symptoms
Most people infected with Salmonella develop fever, diarrhea, and abdominal cramps within 12 to 72 hours after exposure. Although the illness usually lasts 4 to 7 days and most people recover without treatment, some people can become severely ill, requiring medical attention and hospitalization. In these patients, the Salmonella infection can spread from the intestines to the bloodstream and then to other body sites. In this situation, the infection can cause death unless the patient is treated promptly with antibiotics. Infants, elderly people, and people with impaired immune systems are more likely than other people to become severely ill.

Diagnosis and Treatment
Many different kinds of illnesses can cause diarrhea, fever, or abdominal cramps. The only way to tell if Salmonella is the cause of the illness is by doing laboratory tests that identify Salmonella in the stools of an infected person. Once Salmonella has been identified, further testing can determine its specific type, and which antibiotics could be used to treat it.

Every year about 40,000 cases of salmonellosis are reported in the United States, but there are probably many more that are not reported, especially milder cases. The CDC estimates that at least 600 people die every year from acute salmonellosis.

Salmonella infections often do not require treatment unless the patient becomes severely dehydrated or the infection spreads from the intestines. People with severe diarrhea may require rehydration, often with intravenous (IV) fluids. Antibiotics usually aren't needed unless the infection spreads from the intestines. Unfortunately, some Salmonella bacteria have become resistant to antibiotics, largely as a result of the use of antibiotics to promote animal growth.

People with diarrhea caused by Salmonella usually recover completely, although it might be a few months before their bowel habits are entirely normal. A small number of those who are infected will go on to develop joint pains, eye irritation, and painful urination. This is called Reiter's syndrome. It can last for months or years, and can lead to chronic arthritis.

Preventing Salmonella Infection
There is no vaccine to prevent salmonellosis, but you can help avoid it. Most importantly, when you're preparing food, always start by washing your hands with warm water and soap.

For produce:

• Cut away any damaged or bruised areas on fresh fruits and vegetables. Produce that looks rotten should be discarded.
• All produce should be thoroughly washed under running water before eating. Even if you plan to peel the produce before eating, it's still important to wash it first.
• Washing fruits and vegetables with soap, detergent, or other washes is not recommended.
• Firm produce, such as melons and cucumbers, should be scrubbed with a clean produce brush.

For animal products:

• Do not eat or drink foods containing raw eggs, or raw unpasteurized milk. Some foods made with raw eggs include Hollandaise sauce, Caesar and other homemade salad dressings, tiramisu, homemade ice cream, homemade mayonnaise, cookie dough, and frostings.
• Wash hands, kitchen work surfaces such as cutting boards and counters, and utensils with soap and water immediately after they have been in contact with raw meat or poultry.
• Be particularly careful with foods prepared for infants, the elderly, and the immunocompromised. (Mother's milk is the safest food for young infants. Breast-feeding prevents salmonellosis and many other health problems.)
• People who have salmonellosis should not prepare food or pour water for others.
• It might seem obvious, but: wash your hands after contact with animal feces, and make sure children do, too.
• Avoid direct or even indirect contact between reptiles (turtles, iguanas, other lizards, snakes) and infants or immunocompromised persons. Since reptiles are particularly likely to have Salmonella, everyone should immediately wash their hands after handling reptiles. Reptiles (including turtles) are not appropriate pets for small children and should not be in the same house as an infant. In the 1970s, small pet turtles were a common source of salmonellosis in the United States, and in 1975, the sale of small turtles was halted in this country.
• If you are served undercooked meat, poultry or eggs in a restaurant, send it back to the kitchen for further cooking.

Even though we don't usually think about it until an outbreak occurs, many highly effective disease prevention strategies occur every day in our food and water systems; for instance, pasteurization of milk and treating municipal water supplies have been in place for many years.

Improvements in farm animal hygiene, in slaughter plant practices, and in vegetable and fruit harvesting and packing operations can help prevent salmonellosis caused by contaminated foods.

Better education of food industry workers in basic food safety and restaurant inspection procedures help prevent cross-contamination and other food handling errors that can lead to outbreaks.

And every one of us can help reduce the spread of infection by regular handwashing, especially before and after preparing food and using the bathroom.

This article includes information from the US Centers for Disease Control and Prevention (CDC), the US Department of Agriculture Food Safety and Inspection Service, and the CDC's National Center for Zoonotic, Vector-Borne, and Enteric Diseases (ZVED).