Raisins are typically made by sun-drying grapes. They are highly nutritious and considered relatively safe from microbial contamination because they are dried food products, which are safer from contamination by organisms such as bacteria. They contain relatively little moisture/water content, are usually processed at higher temperatures that may kill many potentially pathogenic microbes and often contain preservatives that help to limit the growth of microbes. Despite these benefits, raisins do sometimes become contaminated by harmful bacteria, including various types of salmonella.
Salmonella and How It's Spread
Salmonella bacteria are commonly found in the gastrointestinal track of humans and usually do not cause illnesses. But some strains may produce harmful toxins and may cause serious and even fatal infections in humans. Individuals may become infected due to fecal contaminations of food products including fresh and dried fruits such as raisins. In addition foods such as eggs and raw or undercooked meat products may become contaminated with salmonella. Young children, the elderly and individuals with weakened immune systems due to illnesses or pregnancy are more susceptible to salmonella infections.
Salmonella Symptoms
Symptoms of salmonella infections include diarrhea, which may sometimes be bloody due to the destruction of tissues in the gastrointestinal tract. In addition, persons infected with salmonella may experience fever, nausea, vomiting and abdominal pain. In more severe cases, the bacteria can spread in the blood and cause bacterial sepsis, leading to arterial infections, endocarditis and inflammation of the joints. Severe sepsis may lead to toxic shock and death.
Raisins and Salmonella Contamination
Although the relative risk of raisins contaminated with salmonella is low in comparison to other non-dried foods, there have been previous cases of salmonella-contaminated raisins. These predominantly occur when raisins are mixed with other food products, such as nuts, to make snack mixes. Sometimes these additional components are processed in food plants where they may be more prone to salmonella contamination. In addition, raisins may become contaminated with salmonella due to cross-contamination of leafy green vegetables in salads. Raisins may also become contaminated if they are prepared in a kitchen area with raw meat such as chicken, and the salmonella is transferred from the chicken to the raisins.
Reducing Salmonella Contamination
To reduce the risk of contaminating raisins with salmonella at home, practice sanitary food preparation techniques. This includes making sure your hands are thoroughly cleaned after using the restroom and before preparing foods. It also includes making sure knives and surfaces such as countertops and cutting boards are thoroughly cleaned after preparing raw meat that may harbor the salmonella bacteria, especially if those same surfaces or utensils will be used to prepare foods containing raisins. Whenever possible, using different cutting boards and knives to prepare meats and other non-cooked foods like salads will help to reduce the incidence of salmonella contamination.
References
- U.S. Food and Drug Administration: John B. Sanfilippo & Son, Inc. Voluntarily Recalls Snack Mix and Cashew Products Due to Possible Health Risk
- U.S. Food and Drug Administration: Barcelona Nut Company Recalls Barcelona Nuts Due to the Possibility of Contamination With Salmonella Enteritidis
- National Raisin Company: Frequently Asked Questions.
- World Health Organization: Surface Decontamination of Fruits and Vegetables Eaten Raw: A Review; Larry R. Beuchat
