Influence of Two Levels of Hygiene on the Microbiological Condition of Veal as a Product of Two Slaughtering/Processing Sequences

Abstract

In two experiments involving two groups of 20 calves each, the microbiological condition of veal produced in an alternative (Electrical Stimulation/Hot Boning) and a conventional (No Stimulation/Cold Boning) slaughtering/boning sequence was investigated. Two levels of hygiene were practiced, i.e. (a) “strictly hygienic” by using surgical gloves and disinfected knives, and (b) “hygienic” by using no gloves and only one (visually) clean knife at the start of incision. All hot-boned cuts were sprayed with a 1% v/v L-lactic acid solution, vacuum packed and immersed in icewater. Hot- and cold-boned cuts were stored at 2°C, as vacuum packs during 6 d and exposed to air for an additional week. Using a destructive method, samples for microbiological examination were taken from the 8–10th rib section of the dorsal carcass surface at the end of the slaughterline as well as before boning, and from the epimysium of longissimus cuts immediately after boning, 7 d post mortem (p.m.) upon opening vacuum packs and 14 d p.m. As compared with “hygienic” boning, “strictly hygienic” boning resulted in a significant decrease in aerobic colony count on longissimus cuts from 1.9 to 1.4 log/cm² and from 2.4 to 1.4 log/cm² for alternative and conventional procedures, respectively. An effect of lactic acid decontamination could not be demonstrated earlier than 7 d after opening of vacuum packs (14 d p.m.). Counts of Enterobacteriaceae and yeasts and molds were extremely low under all experimental conditions. No salmonellae could be isolated from any sample.