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Column originally published Jun 24, 2014

It Is Important To Prevent Salmonella Infection

Question: Several weeks ago, our twelve-year-old son was very sick. He vomited for several days and had diarrhea for over one week. He got dehydrated and was admitted to hospital for rehydration; it took a while before he completely recovered. They found Salmonella in his stool, which explained why he became so ill. However, I am still not sure how he picked up the infection, and whether there are ways that we can prevent it from happening again in the future.


Salmonella is one of the most common cause of bacterial gastroenteritis in Canada. You likely have heard of outbreaks of viral gastroenteritis like Norovirus and Rotavirus. Bacteria like Salmonella, Campylobacter, and E coli O157 can also cause outbreaks of gastroenteritis, especially in summer months.

There are many species of Salmonella. They are usually found in the intestines of farm animals as well as chicken and other poultry. Many of these animals don’t appear to be sick; the bacteria just grow and multiply in their intestines. That is why it is difficult to control and prevent Salmonella infection.

When these animals are slaughtered, their intestinal contents often contaminate the meat. With proper cooking, Salmonella and other similar germs are easily killed. However, if the meat is undercooked, Salmonella can survive and cause an infection.

Salmonella can contaminate foods other than meat and chicken. Vegetables can be contaminated when they come in contact with manure from farm animals. Eggs can be contaminated from hens that carry Salmonella in their intestines; eating raw eggs can cause Salmonella infection. Milk can also become contaminated with Salmonella from infected cows. Fortunately, all the milk sold in stores is pasteurized; this markedly reduce the chance of contamination and infection.

Another source of infection happens when meat is being processed. This can happen in slaughterhouse, or when meat is cut and packaged in supermarkets. Grinding meat into hamburger patties can put bacteria deep inside the meat; therefore, the meat has to be well-cooked to prevent infection. Some processors also mechanically tenderize beef and pork by inserting hundreds of fine needles into a piece of meat to break down muscle fibres and connective tissues. It is impossible to tell that a piece of meat has undergone such process. Unfortunately, bacteria on the surface of the meat can be pushed deep inside. If the meat is not cooked adequately, infection can happen.

At home, contamination can happen especially when poultry is being washed. The splash can contaminate the sink and surrounding countertop as well as the hands of the person doing the washing. Cutting boards and knives are easily contaminated. Therefore, kitchen sink, countertop, cutting boards and knives should be sterilized with chlorine every time after raw meat and poultry are being handled in the kitchen. Salmonella and other gastrointestinal bacteria can survive on these items for a long time, and can cross contaminate other food items in the kitchen.

Barbecue is another activity where bacterial contamination can happen easily. Using the same utensils on raw and cooked meat can spell disaster. Salads and cold items need to be stored at the proper temperature, otherwise a few contaminated bacteria can grow and multiply to a large number that can cause serious infection.

Once in a while, processed food can be contaminated with Salmonella and other bacteria that cause gastroenteritis. The Canadian Food Inspection Agency (CFIA) is responsible for alerting consumers about potential contamination and recall of these foods. Just this past week, there is a recall of sprouted chia and flax seed powder contaminated with Salmonella. Most of the time, media like television will report these warnings and recalls, and we need to pay attention to them. You can also check on their website

If you live in a rural area surrounded by farms, your well water can be contaminated by spring runoff. Pet turtles and other reptiles have been found to carry Salmonella in their intestines; families with young children should not have these animals as household pets.

When we ingest Salmonella in contaminated food or other sources, the bacteria can survive stomach acid and multiply in the intestines. It can take several hours to 3 days before symptoms begin. Some can get infected and never show any symptom. Young children and seniors, as well as those who have weakened immune system, can develop serious illness. Vomiting and diarrhea are common, occasionally resulting in dehydration.

It is important to prevent the spread of infection to other family members by good hand washing after going to the toilet. Parents have to be extra careful when changing dirty diapers of children with diarrhea. This is where I would recommend the use of hand sanitizer after washing their hands with soap and water. Those who are sick should not prepare food for other family members.

You may not be able to look back and decide what was the source of your son’s illness. If you are living in a rural area and use well water, it is a good idea to check for bacterial contamination.