In particular the BIOHAZ Panel was asked to: assess the efficacy of this decontamination technique in terms of reduction of surface contamination; evaluate the abiotic and microbiological risks for the carcasses arising from the carcasses and/or the water system when using recycled hot water and suggest control options; identify and define criteria for the HACCP in order to obtain the expected efficacy and to control the possible risk, e.g. the required range of temperature of the recycling water, criteria as fat modifications, denaturation of protein, the frequency of the renewal of the water. According to the remit of this Opinion, the microbiological risks considered only relate to bacteriological and protozoan pathogens, whilst prions are not dealt with.
The published available data on the efficacy of recycled hot water decontamination are very limited and relate only to treatments of bovine and porcine carcasses and only to spray and deluge application techniques. Nevertheless, the available data have shown no significant differences in decontamination efficacy, in terms of microbial reductions achievable on carcasses, between hot potable and hot recycled water.
It was concluded that the application of proper heating regime of recycled water is the main option to control vegetative bacterial cells and protozoan parasites, whereas microbial toxins are not significantly produced and/or are inactivated in the process.
The microbiological risks in the recycled water of main potential concern derive from heat-resistant bacterial spores such as C. botulinum, C. perfringens, C. difficile and B. cereus, however there is a lack of data on the extent of carcass contamination with spores, their germination and inactivation during the recycling process, and the potential for accumulation, during the operations. In order to control the risk related to spores, the BIOHAZ Panel concluded that the best option is to define a proper criteria for the HACCP in order to ensure that the microbiological risk in recycled water is not higher than in hot potable water.
Concerning the abiotic risks, the CONTAM Panel concluded that, if compliance of recycled hot water with the existing chemical criteria for potable water is ensured, it is unlikely that there would be an increased abiotic risk using recycled hot water for decontamination of carcasses as compared to hot potable water decontamination treatment. However, the existing criteria for potable water neither include all chemical contaminants nor veterinary medicinal products, which might contaminate recycled hot water.