The return of the germs
The public at large is quick to take note of substance-related food risks like dioxin or acrylamide contamination. But, frequently it is the microbial risks which are of greater relevance for health. According to the World Health Organisation every year around two million people die around the globe after consuming spoilt food. Even in a high tech country like Germany, around 200,000 cases of illness are notified every year. More than 60,000 are caused by salmonellae. Experts believe that the actual number of cases is in fact ten to twenty times higher. The annual costs incurred by the health care system as a consequence of salmonellae infections alone are estimated to be around EUR 3 billion by the European Union. According to the President of BfR, Professor Andreas Hensel, at the 5th World Congress Foodborne Infections and Intoxications, “Food infections are a global problem. Only if we impose uniformly high hygiene requirements around the world, will we be able - in the long term - to prevent new pathogens from gaining ground and diseases, which had been eradicated in some regions, from flaring up once again.”
More than 400 guests from over 50 countries attended the congress held in Berlin from 7 to 11 June 2004. The congress was organised by the Federal Institute for Risk Assessment in its capacity as a Collaborating Centre for Research and Training in Food Hygiene and Zoonoses of the World Health Organisation and the Food and Agriculture Organisation. It is staged every six years and serves as a forum for the exchange of scientific findings on the causes and spread of foodborne infections and intoxications as well as for the sharing of practical experience in their prevention and control.
The principle “Think global, act local“ also applies to the prevention of foodborne infections and intoxications. In the Member States of the European Union, Japan, Australia and the USA food hygiene problems differ from those in other Asian and African countries. Following the introduction of the “farm to fork” concept, covering the food hygiene process from feed for the animal to the ready-to-consume food on the consumer’s plate, the risks in industrial countries have shifted. Whereas the risk potential during processing has fallen considerably as a consequence of the high hygiene standards and the introduction of the Hazard Analysis and Critical Control Point (HACCP) concept, there are still sanitation problems in conjunction with animal herds and flocks: food-producing animals may carry pathogens without manifesting any clinical symptoms themselves. Their contamination with these germs is, therefore, often overlooked; suitable sanitation measures are often not available. Besides the food-producing animals, storage and preparation are also sensitive areas when it comes to later food infections. This is confirmed by several epidemiological studies. Sensitive foods, either vacuum-packed or packed using protective gas, with a shelf life of up to three weeks are particularly problematic. During longer storage periods Listeria can multiply so fast in meat and fish products packed in this way, especially cold cuts, that the contaminated foods are capable of causing disease.
Another, albeit less critical, point is the recontamination of foods during their preparation. Studies on communal catering as the source of foodborne infections reveal that foods prepared at lunch time and reheated and served in the evening carry a particular risk. In particular toxin-producing pathogens like Bacillus cereus have triggered foodborne infections in this way. These germs constitute a risk especially in foods which consumers consider to be relatively safe like rice, carrots or peas. What can be said of communal catering also probably applies to the home. However, there are not so many documented cases because individual cases are rarely notified.
The enlargement of the European Single Market could lead to the renewed flaring up of diseases which were considered to have been eradicated. For instance, the food hygienists attending the congress warned about the return of trichinellosis. In some regions of the new Member States the trichinella infestation rate of pigs is comparatively high. Hence, there are fears that pork contaminated with trichinella could reach the consumer. What is important here is to contain the risk for consumers in the short term by setting up a comprehensive surveillance system and treating the animal herds.
The growing global food trade and changes in domestic eating habits also bring with them new risks involving old pathogens. Not only prepared salads but also other foods of plant origin which are eaten raw like chickpeas or almonds may be contaminated with salmonellae and, therefore, be a source of food infection. In Asian countries aquacultures are frequently located in the catchment areas of conurbations. Fish and seafood from these regions may, therefore, be contaminated with cholera pathogens or hepatitis A viruses from sewage. Shrimps, mussels or squid, in particular, should not in principle be eaten raw. The favourite saying of English tourists during the 19th century “Cook it, peel it or forget it” should always be taken to heart when travelling.