前增菌培养方法对热损伤单核细胞增生李斯特菌复苏效果观察及应用研究

Observing effect on resuscitating heat-injured Listeria monocytogenes by pre-breeding method

目的：观察前增菌培养方法对热损伤LM的复苏/恢复情况以及在市售熟肉制品LM污染调查检测中的运用效果,探索受损伤LM的增菌培养方法,提高食品LM检出率。方法：LM参考菌株经61℃5 min处理,制备热损伤菌液,采用Alanin Martin等推荐的LM前增菌液和LM国标方法LB1、EB增菌液对热损伤细菌进行复苏/恢复,记录、分析细菌增殖、恢复情况。将LM前增菌培养方法与国标法结合（改良法）,用于熟肉制品LM污染调查检测,并与单纯国标法检测结果进行比较,得出结论。结果：热损伤LM经前增菌液培养4-5 h后,基本完成复苏/恢复过程,并开始明显增殖,24 h培养后,菌数较直接使用LB1、EB增菌液培养的菌数增长明显（约增加10^2倍）;热损伤LM在LB1、EB增菌液培养早期,菌数一度减少,机理尚需进一步研究。前增菌培养方法与LM国标法结合（改良法）用于熟肉制品LM污染调查,较单纯使用国标法的检出率明显提高（χ^2=4.68,P〈0.05）。结论：热损伤LM在LB1、EB增菌液中复苏/恢复比较缓慢,AlaninMartin等提出的LM前增菌方法对热损伤LM有明显的复苏/恢复效果,建议对加工食品进行LM检测时,在现行LM国标检测方法的基础上,适当增加前增菌培养过程,以提高LM的检出率。

Objective：To observe the resuscitating status of the heat-injured Listeria monocytogenes（L.monocytogenes）and the pre-breeding effect of delicatessen meat L.monocytogenes detection.Methods：The heat-injured bacterial cells were prepared by heating the cells to 61℃ for 5 minute.Resuscitating heat-injured cells by the pre-breeding media of Alanin Martin by LB1 or EB media of the routine method.The routine method and the one combining with the pre-breeding method were separately used to detect L.monocytogenes in these delicatessen meat samples.Results：The heat-injured cells were resuscitated and increased after 4 or 5 hours in the prebreeding media.The positive rates using the routine method combining with the pre-breeding were higher than those by the routine method（χ^2=4.68,P〈0.05）.Conclusion：The pre-breeding media is better than LB1 and EB media in resuscitating heat-injured L.monocytogenes.It is suggested to detect foods with L.monocytogenes using the routine method combining with the pre-breeding.