Contact: Aga Haupt
A recent Mississippi State study finds that so-called ready-to-eat shrimp can be a reservoir of antibiotic-resistant bacteria and could be dangerous to people with compromised immune systems.
University microbiologist Douglas L. Marshall recently concluded a two-year study to determine if ready-to-eat shrimp is contaminated with bacteria that are resistant to antibiotics. The professor of food science and technology said he and graduate student Gianna Duran analyzed 13 packages of prepared shrimp products, including shrimp cocktails and shrimp salads available in grocery outlets.
"We found 657 different cultures resistant to antibiotics," Marshall said. Of the 131 different species of bacteria found, some were resistant to the most frequently prescribed antibiotics and some were capable of causing diseases, he added.
"That's not what we expected," he said. "We expected to find bacteria associated with spoilage, not those associated with human disease. There shouldn't be any illness-causing bacteria on a ready-to-eat product.
"Not only could the bacteria cause consumers to become ill, but some also are resistant to the antibiotics that would be used to treat those illnesses," Marshall observed.
Escherichia coli, salmonella cholerasius and staphylococcus aureus are among the highly resistant bacteria the MSU team found in the shrimp products.
According to the U.S. Food and Drug Administration's Center for Food Safety and Applied Nutrition, E. coli can cause urinary tract infections, neonatal meningitis and intestinal diseases, while salmonella infections also can lead to intestinal diseases.
The staphylococcus bacteria has the potential to cause various infections, including pneumonia and meningitis, as well as food poisoning and toxic shock syndrome.
"These bacteria are around us all the time and they rarely lead to illness, so for the average consumer the ready-to-eat shrimp products are probably not an issue," Marshall said. "People with compromised immune systems, however, including the very young, very old, people infected with HIV, cancer and chemotherapy patients, and people taking immune system suppressors, should be more careful."
Marshall recommends persons in the high-risk categories re-cook prepared seafood products to kill possible bacteria.
Marshall said the United States imports large quantities of seafood, including shrimp from developing nations where good sanitary practices--including water quality and employee hygiene--might be suspect. In his opinion, the industry needs to do a better job of preventing contamination.
"The development of antibiotic-resistant microbes is a global concern," Marshall said. "Because of the overuse of antibiotics, we might one day come to the point where we won't be able to cure diseases we once could because of the increased resistance of these bugs."