Ayebah Beatrice, Hung Yen-Con, Frank Joseph F
Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223, USA.
J Food Prot. 2005 Jul;68(7):1375-80. doi: 10.4315/0362-028x-68.7.1375.
Biofilms are potential sources of contamination to food in processing plants, because they frequently survive sanitizer treatments during cleaning. The objective of this research was to investigate the combined use of alkaline and acidic electrolyzed (EO) water in the inactivation of Listeria monocytogenes biofilms on stainless steel surfaces. Biofilms were grown on rectangular stainless steel (type 304, no. 4 finish) coupons (2 by 5 cm) in a 1:10 dilution of tryptic soy broth that contained a five-strain mixture of L. monocytogenes for 48 h at 25 degrees C. The coupons with biofilms were then treated with acidic EO water or alkaline EO water or with alkaline EO water followed by acidic EO water produced at 14 and 20 A for 30, 60, and 120 s. Alkaline EO water alone did not produce significant reductions in L. monocytogenes biofilms when compared with the control. Treatment with acidic EO water only for 30 to 120 s, on the other hand, reduced the viable bacterial populations in the biofilms by 4.3 to 5.2 log CFU per coupon, whereas the combined treatment of alkaline EO water followed by acidic EO water produced an additional 0.3- to 1.2-log CFU per coupon reduction. The population of L. monocytogenes reduced by treatments with acidic EO water increased significantly with increasing time of exposure. However, no significant differences occurred between treatments with EO water produced at 14 and 20 A. Results suggest that alkaline and acidic EO water can be used together to achieve a better inactivation of biofilms than when applied individually.
生物膜是加工厂食品污染的潜在来源，因为它们在清洁过程中经常能在消毒剂处理下存活下来。本研究的目的是调查碱性和酸性电解水联合使用对不锈钢表面单核细胞增生李斯特菌生物膜的灭活效果。生物膜在含有单核细胞增生李斯特菌五菌株混合物的胰蛋白胨大豆肉汤1:10稀释液中，于25℃在矩形不锈钢（304型，4号表面光洁度）试片（2×5厘米）上培养48小时。然后将带有生物膜的试片用酸性电解水或碱性电解水或先用碱性电解水再用14和20安培产生的酸性电解水处理30、60和120秒。与对照相比，单独使用碱性电解水对单核细胞增生李斯特菌生物膜没有显著的减少作用。另一方面，仅用酸性电解水处理30至120秒，可使生物膜中活菌数量每试片减少4.3至5.2个对数CFU，而碱性电解水后接酸性电解水的联合处理每试片可额外减少0.3至1.2个对数CFU。用酸性电解水处理后，单核细胞增生李斯特菌数量随暴露时间增加而显著减少。然而，14和20安培产生的电解水处理之间没有显著差异。结果表明，碱性和酸性电解水联合使用比单独使用能更好地灭活生物膜。
