Food poisoning is actually a result of consumption of food that is contaminated.
Contamination of the food can happen at any stage of its production and preparation. Generally, before the preparation the food has to be properly washed. Then the peel of certain fruit and vegetables is removed. In process of preparation hands need to be clean and previously washed with soap. In many kitchens in restaurants people who are manipulating with food need to wear rubber gloves. This way the spread of possible infective agents and their products is limited.
If food is cooked or fried enough majority of infective agents are eliminated. If the food is not kept in a fridge or at right temperature it can also become contaminated. Most people pay attention to the expiring date of food products. This is important as food poisoning may occur if one eats something that is out of date which can cause health problems.
Cross contamination occurs when infective agents, particularly bacteria are spread from equipment and the surface where the food is being prepared onto the food.
This way the food gets contaminated and if one eats this food without further thermal processing he/ she risks food poisoning. The most dangerous are salads and sandwiches.
Sources of Contamination
Bacteria are the most common cause of food poisoning. Salmonella, Campylobacter, Escherichia coli,
and Listeria are only several bacteria that can lead to food poisoning. Campylobacter is present in uncooked poultry and meat and inappropriately pasteurized milk. Salmonella can be present in poultry and raw meat. Eggs are the most common source of food poisoning with Salmonella. Even unpasteurized milk can contain Salmonella bacterium. Listeria is a bacterium that can be easily found in butter and pâté. Even cheeses such as camembert or brie and soft blue cheese can contain Listeria. Listeria can also contaminate smoked salmon. Escherichia coli mostly contaminates beef so if this meat is not cooked enough the chance that the food poisoning will occur is greater.
The most common viruses that lead to food poisoning include the rotavirus and the norovirus. Both of these are transferred from the contaminated hands after a person has used the toilet and then without proper hand hygiene started to prepare the food.
There are numerous parasites that can contaminate food and lead to food poisoning. Toxoplasma gondii is only one of them. This parasite lives in the digestive system of infected cats and their urine and feces contain huge number of these parasites. Parasites can be transferred onto the food especially vegetables and in case that vegetables are not properly washed the parasite enters the human body. Even some meat can contain Toxoplasma gondii and if not cooked enough it can be one more source of the food poisoning.
Oily fish can get contaminated with polychlorinated biphenyls which are especially toxic for unborn babies. This is why pregnant women have to avoid eating oily fish as much as possible and limit the weekly intake to only two portions.
Certain fish may contain mercury. If this metal is present in large amounts it can also be responsible for severe damage of the unborn baby. Avoiding sharks, swordfish and marlin is good as these fish can contain plenty of mercury.