Salmonella Outbreak in US (Fall 2012)
Briefly, what is Salmonella?
Salmonella is a genus of bacteria which can infect humans. Infection with most Salmonella species causes gastro-enteritis (gastrointestinal discomfort such as diarrhea, vomiting, abdominal pain and dehydration). Infection with a strain called Salmonella typhi can cause a systemic fever (Typhoid fever).
How does Salmonella get into the food supply? Can any type of food carry Salmonella?
Salmonella bacteria live in most warm-blooded animals (cows/beef), birds (chicken and eggs), reptiles (pet turtles or lizards), and in the environment (contaminated water). It is transmitted by the fecal-oral route to humans. This means that animal products can become infected with the bacteria, often during processing. Contamination could be due to incorrect food preparation techniques (incomplete cooking or lack of refrigeration) or contact with infected work surfaces. This can spread to other foods in manufacturing plants leading to many types of contaminated food and drink. In addition, infected people with poor personal hygiene can spread the bacteria via food to other people. “Typhoid Mary” is an example of an infected carrier who worked in the food industry. She unknowingly (?), passed the bacteria and the disease onto many people, making them sick.
How is a Salmonella infection treated?
Most food poisonings caused by Salmonella are self-limiting. That is to say, it will go away on its own. Dehydration due to diarrhea and vomiting is a concern, so the patient must make every effort to stay hydrated during the infection. In more severe cases, or if the infection is systemic as in Typhoid fever, antibiotics are given.
Can Salmonella ever be eradicated?
Eradication is probably impossible since most animals have one strain of Salmonella or another living in their G-I systems. Preventing human disease is a more realistic goal. Proper sewage treatment, chlorinated water, pasteurization of milk products, correct cooking of poultry, eggs and meat and improved personal hygiene prior to food handling will all help to insure that foods do not become contaminated with Salmonella.
What should we do if we own a contaminated product?
Return it to the store of purchase or throw it out. If a product is recalled due to possible infection, even if you are not sure if your jar contains the bacteria – get rid of it. DO NOT EAT IT!
How would we know whether a food product has Salmonella or not, if we haven't been told in advance?
Unfortunately, there is no way to know if foods are contaminated. Often produce is contaminated due to crops and livestock being in close proximity to one another. Since the contamination is on the surface of the produce, it is always a good idea to wash all fresh produce very well before consumption. Likewise, it is almost impossible to tell if packaged foods contain Salmonella. This is why manufactures recall all products made on the same machinery as an infected batch. Obviously, if the color or smell of a product is wrong – do not eat it.
As a scientist, what worries you most about the fairly frequent news of Salmonella outbreaks in the US?
My concern with Salmonella outbreaks, as well as many other types of bacterial infections, is the overuse of antibiotics. Antibiotics are a great tool for combating invasive bacteria. However, the more they are used, the more likely bacteria will become resistant. Drug companies are always trying to develop newer and better drugs for fighting resistant strains. It is a delicate balance between prescribing antibiotics when needed, and not overusing them. In many cases of Salmonella food poisoning, it might be better not to use antibiotics since often these infections are self-limiting.
Lee Ann Schein, Ph.D is an Assistant Professor, Department of Pharmacology at Robert Wood Johnson Medical School. She is the Course Director for Mechanisms of Disease and Defense, a first year medical school course. She is also the Course Director of Microbiology and Immunology Course in the Master in Biomedical Sciences Program (RWJMS). Dr. Schein teaches immunity and microbiology. Contact: Lee Ann Schein, Ph.D firstname.lastname@example.org