Question: "Why are there constantly new pathogens arising?"

Answer: The answer to this question is not easy or straightforward. There are several explanations as to why there is a trend for ³popular² food borne pathogens.

Firstly, the foods we eat are changing to meet consumer demands. Many new food processes are developed to meet the demands of the consumers. Sometimes these new processes change the environmental conditions and as a result can act as a portal for pathogens to survive and possibly cause food borne disease.

A second explanation why certain pathogens become reported as causative agents more often is because of the development of more sensitive assay tests or by more indepth investigations for certain pathogens. Another way that pathogens become prevalent is by the passing of virulence genes onto different strains of bacteria. Once the bacterium acquires the virulence genes from another pathogenic organism, the ³new² bacterium is capable of causing food borne disease. E. coli O157:H7 is one example of how it ³evolved² to become a pathogen by accepting the toxin genes from Shigella. This new strain O157:H7 is capable of producing a Shigella toxin that causes adverse effects in people that are most often immunocomprimised such as young, old or persons suffering from a compromised immune system. In some cases, more than one of these routes are necessary to yield a new pathogenic strain.

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