The news has lately been abuzz about food contaminated with Salmonella. In the US, it’s fresh lettuce, tomatoes, peanut butter, and pistachios. In the Philippines, pistachios and products containing peanut butter from the US were taken off the shelves and the factory producing a long standing local brand of peanut butter was closed until they could comply with Good Manufacturing Practices or GMPs.
People on the news tell us Salmonella is a bacterium that is harmful to humans, and that poor hygiene and sanitation cause contamination.
Salmonella is actually not a single kind of bacterium but a whole category of bacteria to which several species belong. Several of these species cause infections, usually referred to as food poisoning. Among the diseases caused by ingesting (eating) live Salmonella bacteria is Salmonellosis, which is caused by several kinds of Salmonella, including Salmonella choleraesius. Symptoms of this disease commonly occur within 12–36 hours after infection, but the range may vary from 5–7 hours. Common symptoms are diarrhea, abdominal pain, chills, fever, and vomiting, which may last several days.
Symptoms of Infection
A more dangerous species within the Salmonella group of bacteria is Salmonella typhi, which causes typhoid fever. Although typhoid fever is treatable and is not commonly fatal, there still occurs a 10%– 30% fatality rate. Symptoms of typhoid fever include diarrhea, vomiting, and continuing very high fever that causes delirium. The disease lasts for around four weeks and relapse is common. Another disease, paratyphoid fever has similar but less severe symptoms. It lasts some two weeks and is caused by Salmonella enteritidis.
The severity of symptoms depends on the resistance of the infected person. So infants, children, the elderly, and those with weakened immune systems are more likely to develop more severe symptoms.
Salmonella-caused diseases are transmitted via ingestion of living bacteria. So the main sources of infection would be the water we drink and the food we eat. Although Salmonella is commonly associated with poultry and poultry products— eggs, poultry meat (chicken, duck, ostrich, etc.), innards—all foods can potentially carry the bacteria.
Salmonella gets around by hitching a ride in the feces and urine of an infected person. If the infection spreads to our water supply (either because water is not treated or sewage comes in contact with water pipes) then there is a potential for an outbreak.
If the contaminated water is used for washing, then this contaminates all the food, food contact surfaces, and the hands of everyone who uses the water. The bacteria then gets a chance to infect every healthy person who drinks or eats the food contaminated by feces or urine.
Another path it might take is if a person with the infection uses the bathroom and does not wash hands properly (or does not wash hands at all!) and then handles the food or the utensils used in preparing it.
One interesting incident of Salmonella contamination occurred several years ago when a very diligent worker, who owned a small poultry operation in her backyard, contaminated an entire processing plant. The Salmonella bacteria got into her hair when she swept her yard prior to coming to work. This airborne form of Salmonella is not directly contagious, but it poses a risk for manufacturers and restaurant owners since this can get into food and stay there for a long time. The manufacturer in the story now observes a strict routine where all employees take a shower and change into their work clothes on site prior to entering the production area.
The best way to keep your facilities safe from Salmonella is by following GMPs. This means making sure your water is clean, your facilities are regularly cleaned and sanitized, you have adequate facilities for your employees, and your employees are trained on correct hand-washing procedures.
Salmonella is easy enough to kill. For food contact surfaces and equipment normal cleaning and sanitizing is sufficient. For food, the process that kills this bacteria has been around for almost 150 years. It’s called pasteurization. Salmonella is so easily destroyed by heat that fresh eggs can be pasteurized in their shells without the egg actually getting cooked. After pasteurization the content of eggs remain fluid and still considered raw.
Print ed: 06/09