Bacterial cross-contamination of food (spreading bacteria from a contaminated item to a non-contaminated one) can occur during food preparation in a kitchen. In a presentation at the European Symposium on Food Safety, Professor Donald Schaffner talked about what can affect the cross-contamination; his study analyzed the bacterial transfer from solid surfaces to raw food items and vice versa, in different experimental conditions.
Food Contamination: Bacteria
A food item is contaminated when it contains species or chemical compounds which are toxic, and which can affect the health of the people who eat it. When food contains bacterial strains, we talk about bacterial contamination.
Depending on the nature of the bacteria and the effect they can have on human body, the consequences of the contamination can be very different. In the majority of cases, these microorganisms cause intense but short infections and irritations in the gastrointestinal system, without any long term effect.
In rarer cases, however, food may contain very toxic strains; the effects can be long term and much more serious, even resulting in fatalities. The E. coli O104:H4 outbreak in Germany in spring 2011 is an example of this; the presence of this strain in vegetables (sprouts) caused 48 deaths.
Bacteria Contamination: When It Can Occur
Fresh products such as vegetables, diary products or raw meat already contain some microorganisms; in other cases, bacteria can grow during the various phases of the production, for instance during storage.
Some of these strains can be eliminated with appropriate techniques; treatment at high temperature (pasteurization), for instance, can greatly reduce the bacteria population, as the heat kills these species.
Even considering all safety measures, however, there is always a risk that the food can become contaminated.
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