Livelli di contaminazione microbica di alimenti marini congelati e surgelati

The Authors carried out a microbiological survey on frozen and deep-frozen shellfish products in order to evaluate the significance of microbial contamination as a marker of quality of frozen marine food and their manufacture. 125 different products on sale by retail shops were analysed, particularly 46 samples of hen clams, 47 samples of calamaries and cuttle-fishes and 32 samples of shrimps were examined for bactcrial count, total and faecal coliforms, faecal streptococci, sulphite reducing thermoresistant spore forming bacteria, staphylococci, salmonellae and vibrios. In accordancc with the most common microbiological standards the Authors found 24 samples (19,2%) microbiologically unacceptable. The highest level of unfitness was detectcd in deep frozen hen clams (58%), instead of the samples of mollusks that were found constantly acceptable; the detectcd levels of unfitness were of 16 and 15% respectively in the samples of deep frozen shrimps and in frozen hen clams. Conscquently the survey revealed a remarkablc number of microbiologically unacceptable shellfish products among that ones on sale and the most sensitive markers appeared microbial piate count at 37°C, faecal streptococci and Staphylococcus aureus.