湛江东海岛文蛤模拟加工的细菌学分析

用行业标准分别对文蛤原料、清洗并热烫后和冷冻0.5 h后等加工工序中文蛤细菌总数、大肠菌群数、粪大肠菌群数、副溶血性弧菌、金黄色葡萄球菌和沙门氏菌进行了检验.结果发现,湛江东海岛近海文蛤原料的细菌总数为(4.0±0.1)×105 cfu/g,清洗并热烫和再冷冻0.5 h后对细菌总数的影响不明显.文蛤原料大肠菌群数为(790.7±21.3)MPN/g,清洗并热烫后大肠菌群数明显降低至(19.4±1.3)MPN/g,再冷冻0.5 h后大肠菌群数为(18.3±1.1)MPN/g.文蛤原料粪大肠菌群数为(817.5±19.8)MPN/g,清洗并热烫后粪大肠菌群数明显降低至(194.2±10.2)MPN/g,再冷冻0.5 h后粪大肠菌群数为(180.6±11.3)MPN/g.文蛤原料、清洗并热烫后和再冷冻0.5 h后副溶血性弧菌的检验结果均为＜3 MPN/g;均未检出凝固酶阳性的金黄色葡萄球菌和沙门氏菌.可见湛江东海岛近海文蛤的细菌污染主要是大肠菌群和粪大肠菌群,经清洗并热烫和再冷冻0.5h处理,能明显降低大肠菌群和粪大肠菌群数量.

Bacteriological Analysis of Simulatively Processed Meretrix Meretrix Linnaeus in the Offing of Donghai Island (Zhanjiang)

The Most Probable Number Methods (MPN) of Food Trade Standards were employed to enumerate the total bacteria count, MPN, faecal coliforms, Vibrio parahaemolyticus, Staphylococcus aureus and Salmonella in the process simulation of Meretrix meretrix Linnaeus from the offing of Donghai Island (Zhanjiang, China). The results showed that the treatments of cleaning and scalding with hot water and freezing for 0.5 h showed a little effect on the total bacteria count of the raw material of M. meretrix which was (4.0±0.1)×105 cfu/g. It was also found that cleaning and scalding with hot water markedly reduced the MPN of the raw material of M. meretrix from (790.7±21.3) MPN/g to (19.4±1.3) MPN/g, and a further freezing treatment (0.5 h) decreased the value to (18.3±1.1) MPN/g. Faecal coliform of the raw material of M. meretrix was (817.5±19.8) MPN/g, which markedly fell to (194.2±10.2) MPN/g by cleaning and dipping into thermal water and to (180.6±11.3) MPN/g by further freezing for 0.5 h. V. parahaemolyticus in the raw material and the processed M. meretrix was less than 3 MPN/g. Besides, no coagulase-positive S. aureus and Salmonella were found in every products of the simulatively processed M. meretrix. M. meretrix in the offing of DonghaiZhanjiang was mainly contaminated by coliform strains and faecal coliforms which can be significantly eliminated by cleaning and dipping into thermal water then freezing for 0.5 hours.