Is It Possible to Prevent Salmonella Infections?
For all Salmonella diseases, the key to prevention is proper hygiene and enforcement of public health rules and regulations. Proper hygiene starts with hand washing with soap and water before eating and especially after handling any raw foods such as eggs, meat, or produce. Avoiding direct contact with carriers of Salmonella (for example, turtles, snakes, chickens, pigs, and typhoid patients) reduces the chance of infection. Public-health practices such as chlorination of drinking water, enforcing restaurant cleanliness and employee hand washing, and not allowing human carriers of Salmonella to work in the food-handling industry further reduce the chance of Salmonella exposure. Perhaps the most famous failure of public health measures was in 1907 when a cook named Mary Mallon (Typhoid Mary) was suspected of infecting hundreds of individuals with a S. typhi serovar.
The CDC issues recalls of items, usually processed foods or vegetables, found to be contaminated with S. spp or other infectious or poisonous agents. People that take heed of these warnings and the accompanying advice reduce their chance of infection. In the past several years, recalls and reports of S. spp contamination of ground turkey (reportedly a drug-resistant strain in 2011), eggs, parsley, dog food, and other items have been publically announced. Most recently, mangoes, cantaloupes, and Wawa Fruit Cups have been cited or recalled because of S. spp contamination. The source of cantaloupe contamination has been traced in August 2012, to Chamberlain Farms Produce; the company has suspended all melon shipments. As of August 2017, the U.S. Food and Drug Administration (FDA) and CDC recommends that Maradol papayas from Caribena, Cavi, and Valery be avoided. About 141 individuals (with 45 hospitalized) in 19 states so far have been diagnosed with the disease. The source is suspected to be contaminated papayas from Mexico.
Currently, there is no vaccine available to prevent salmonellosis, and the CDC does not recommend the general population be vaccinated against S. typhi serovars. However, the CDC does recommend that individuals going to developing countries where typhoid fever is endemic (some regions in Africa, Asia, and Latin America) be vaccinated with a typhoid vaccine. There are two types of vaccines currently available to individuals. Ty21a is an oral vaccine that requires four doses administered two weeks before travel, while ViCPS vaccine is injected once and requires only one dose administered one week before travel. The Ty21a immunization requires a booster every five years with the minimum vaccination age of 6 years, while ViCPS requires a booster every two years with a minimum vaccination age of 2 years. Work is in progress to develop additional vaccines for all Salmonella infections.