Microbial Contamination In Chilled Beef Process And Effects Of Sterilization

The quality of chilled beef is an important indicator which can measure the commercial value of chilled beef. However, the shelf-life of chilled beef shorten and safe risk increased which was caused by the growth of contaminated microorganism have tended to restrict the rapid, healthy, and sustainable development of Chinese beef manufacturers. The microbial contamination of chilled beef was effected by the slaughter conditions, such as dehiding, evisceration, split half, trimming, and the personnel, tools, and equipments used in the carcass segmentation process. It can reduced microbial contamination of chilled beef and improve its quality by the means of effective carcass spraying technology and reasonable surface disinfection operation.The study researched the conditions of the steps of slaughter and carcass segmentation process. Furthermore, the effect of carcass spraying technology and the method of surface disinfection operation on microorganisms'number had been probed. The results of this study were as follows:1. The beef cattle slaughter processes in an enterprise of the slaughtering were investigated, and number of microorganisms on the carcass surface was analysis statistically. This indicated that the operations of dehiding give the most contamination to the beef carcasses in the slaughtered process. The number of the microorganism on the surface of beef carcasses between the steps had significant correlation. And the contamination of the carcass which was trimmed had the highest significant correlation to the eviscerated carcasses. It said that the evisceration was another step which gave the most contamination.2. Different spray methods were chosen to be studied. The reduction of microbiological counts in beef carcasses when sprayed with water was 0.62lg(cfu/cm~2), while spraying with 2% lactic acid reduced numbers of bacteria on brisket was 1.06lg(cfu/cm~2), however it could not reduce numbers of bacteria on the whole carcass, neck, legs and buttocks obviously. Hot water treatment(>74℃) reduced numbers of bacteria on the whole carcass was nearly 1.0lg(cfu/cm~2), and the reduction of brisket was more then1.5lg(cfu/cm~2), the numbers of bacteria on neck had obvious results. Spraying with hot water and lactic acid could have a significant effective reduction to the beef carcasses.3. Spraying with 2% lactic acid reduced microbiological counts on beef cooling mature carcass, the reduction became higher than the spraying. It said that lactic acid could have an effective effort in the chilling process.4,The microbiological counts on tools, surfaces was big in the cutting process before working. The contamination of beef had a significant correlation with the slicing bench, boning bench, slicing belt. The numbers of bacteria on the slicing bench, boning bench, and boning belt would be less with the longer of working time.5,The reduction of microbiological counts of 3‰peroxyacetic acid was higher then 75%ethanol. 4.5‰peroxyacetic acid could have a satisfactory result of coliforms to the boning bench. But the reduction of the total counts of microorganisms and Pseudomonas had no significant difference between 6.0‰peroxyacetic acid (7.5‰peroxyacetic acid) and 3.0‰peroxyacetic acid.