Van Netten P, Valentijn A, Mossel D A, Huis in't Veld J H
Inspectorate of Health Protection, Hertogenbosch, Utrecht University, The Netherlands.
J Appl Microbiol. 1998 Apr;84(4):559-67. doi: 10.1046/j.1365-2672.1998.00382.x.
Lactic acid decontamination (LAD) may adapt pathogens to lactic acid. Such organisms may have an increased resistance to acid and can contaminate meat after LAD. The survival and growth of acid adapted Campylobacter jejuni, Salmonella typhimurium. Escherichia coli O157:H7 and Staphylococcus aureus inoculated on skin surface of still warm pork belly cuts 2 h after LAD was examined during chilled (4 degrees C) storage and refrigeration abuse equivalent to 12.5 degrees C. Lactic acid decontamination included dipping in 1, 2 or 5% lactic acid solutions at 55 degrees C for 120 s. Lactic acid decontamination brought sharp reductions in meat surface pH, but these recovered with time after LAD at approximately 1-1.5 pH units below that of water-treated controls. A sharp decrease in the number of cfu of pathogens occurred on chilled 2-5% lactic acid treated pork belly cuts when the skin surface was less than pH 4.8-5.2. The reductions ranged from 0.1-0.3 log10 cfu cm-2 for E. coli O157:H7 to over 1.7-2.4 log10 cfu cm-2 for Camp. jejuni, respectively. Increase in storage temperature from 4 to 12.5 degrees C reduced delayed decrease in numbers of all pathogens except Camp. jejuni by a factor of two. Deaths in Camp. jejuni at 12.5 degrees C slightly exceeded those at 4 degrees C. After the initial sharp decline, the number of cfu of mesophilic pathogens decreased gradually at a rate similar to that on water-treated controls. Growth of all mesophilic pathogens except Camp. jejuni on 2-5% LAD meat occurred during storage at 12.5 degrees C when the meat surface pH exceeded 4.8-5.2, and was slower than on water-treated controls. Low temperature and acid-adapted E. coli O157:H7, Salm. typhimurium and Staph. aureus, and acid adapted Camp. jejuni that contaminate skin surface after hot 2-5% LAD, did not cause an increased health hazard, although microbiota and intrinsic parameters (lactic acid content, pH) were created that could advantage their survival and growth.
乳酸去污处理（LAD）可能会使病原体适应乳酸。这类微生物可能对酸的耐受性增强，并且在乳酸去污处理后可能会污染肉类。研究了在乳酸去污处理2小时后，接种在仍温热的猪肚切块皮肤表面的空肠弯曲菌、鼠伤寒沙门氏菌、大肠杆菌O157:H7和金黄色葡萄球菌在冷藏（4℃）储存以及相当于12.5℃的冷藏滥用条件下的存活和生长情况。乳酸去污处理包括在55℃下将猪肚切块浸入1%、2%或5%的乳酸溶液中120秒。乳酸去污处理使肉表面pH值急剧下降，但在乳酸去污处理后，pH值会随着时间的推移恢复，比水处理对照组低约1 - 1.5个pH单位。当皮肤表面pH值低于4.8 - 5.2时，在冷藏的2 - 5%乳酸处理的猪肚切块上，病原体的菌落形成单位（cfu）数量急剧减少。减少幅度分别为：大肠杆菌O157:H7为0.1 - 0.3 log10 cfu/cm²，空肠弯曲菌超过1.7 - 2.4 log10 cfu/cm²。储存温度从4℃升高到12.5℃，除空肠弯曲菌外，所有病原体数量的延迟减少幅度降低了一半。在12.5℃时空肠弯曲菌的死亡数量略超过4℃时的死亡数量。在最初的急剧下降之后，嗜温病原体的cfu数量以与水处理对照组相似的速率逐渐减少。当肉表面pH值超过4.8 - 5.2时，在12.5℃储存期间，除空肠弯曲菌外，所有嗜温病原体在2 - 5%乳酸去污处理的肉上均有生长，且生长速度比水处理对照组慢。尽管创造了有利于微生物生存和生长的微生物群落和内在参数（乳酸含量、pH值），但在热的2 - 5%乳酸去污处理后污染皮肤表面的低温和酸适应型大肠杆菌O157:H7、鼠伤寒沙门氏菌、金黄色葡萄球菌以及酸适应型空肠弯曲菌并不会增加健康危害。
