In the wake of the “food crises” we have experienced over the last few years, the recent scandal connected with the unexpected detection of horsemeat in prepared food has yet again raised questions about adequate screening of the food chain as well as underlining the importance of food testing in the laboratory. The Department of Food Science at the University of Liege, led by Prof. Georges Daube has been preoccupied with the issue of food-testing for a long time. Together with Bernard Taminiau, he has just developed a system for the microbiological investigation of food— an analyis method known as the Targeted Metagenomics of Microbial Biodiversity — which has aroused a lot of interest in the food processing sector. Based on the sequencing of DNA strands of germs to be analysed, this method makes it possible to precisely identify the germs or to characterize them if they are not yet known. This new method also makes it possible to count the germs or at least to determine the proportions of the different types of germs relative to each other. The next objective which the researchers from Liege have set themselves is to precisely determine the exact quantities of each germ.

“Over the last few years, we have seen many food crises all of which have occurred as a result of animal feed contamination: the inclusion of fat in animal feed in the case of the dioxin crisis; meat and bone meal given to cattle in the case of mad cow disease, etc. This means that we must comprehensively screen all those stages of the food-chain where contamination by germs is likely to occur, in order to ensure that the food at the end of the food-chain is safe”, explains Professor Georges Daube.

Since 2006, new food legislation has been in place: The General Food Law, which encompasses the general rules applicable to the food industry. In particular, it specifies that a given food item can only be sold on the market if it represents no hazard to the health of the consumer: there must be an absence of pathogenic micro-organisms or toxic substances. In short, an item of food must not be contaminated and cause illness. At each stage of the food-chain, the European legislative framework imposes a control method known as HACCP (Hazard Analysis & Critical Control Points). In the wake of this legal framework, the European Union has enacted a series of implementing regulations stating the obligations of “operators” on one hand, that is to say, each link in the food-chain including breeders, abattoirs, meat-cutting plants and distributors, and on the other hand, the rules for official control.

The implementing regulation applying to operators also includes a set of criteria applicable to micro-organisms to which all food circulating within the European Union must comply. Among these criteria are food safety criteria which directly concern bacteria that are dangerous for the health of the consumer, and criteria relating to the manufacturing process described as process hygiene criteria which must be respected by all food-processing companies within the European Union. The acceptability of a product, group of products or process is decided based on these microbiological and food-quality criteria based on the absence of bacteria, or at least a sufficiently low level of bacteria per unit volume or surface area. In other words, the objective is that a given product should remain edible from the moment of its manufacture to the moment it is consumed before its use-by date. Being classed as edible implies that the product in question does not contain too many pathogenic micro-organisms. Some pathogenic germs are dangerous at low concentrations and must therefore be present in foods in quantities lower than 1/25 gr (1 germ per 25 gr), while others which are a lot less dangerous, can be ingested at concentrations of up to a million without causing infection or poisoning. In other words, a consumer will only be sick if he or she ingests micro-organisms at concentrations higher than those known as the “minimum infectious dose”.