Allan J T, Yan Z, Genzlinger L L, Kornacki J L
Center for Food Safety and Department of Food Science, The University of Georgia, Griffin, Georgia 30223, USA.
J Food Prot. 2004 Dec;67(12):2661-5. doi: 10.4315/0362-028x-67.12.2661.
The survival of three foodborne pathogens (Listeria monocytogenes, Yersinia enterocolitica, and Salmonella) attached to mortar surfaces, with or without biological soil (porcine serum) and incubated at either 4 or 10 degrees C in the presence of condensate, was evaluated. Soiled and unsoiled coupons were inoculated by immersion into a five-strain cocktail (approximately 10(7) CFU/ml) of each organism type and evaluated. Coupons were incubated at 25 degrees C for 2 h to allow attachment of cells, rinsed to remove unattached cells, and incubated at either 4 or 10 degrees C at high humidity to create condensate on the surface. Sonication was used to remove the attached cells, and bacteria (CFU per coupon) was determined at 9 to 10 sampling periods over 120 h. Yersinia populations decreased more than 5 log units in the presence of serum in a 24-h period. Listeria and Salmonella had better survival on mortar in the presence of serum than Yersinia throughout the 120-h incubation period. Populations of L. monocytogenes declined more rapidly at 10 than at 4 degree C after 24 h. In general, differences in temperature did not affect the survival of Salmonella or Yersinia. Serum had a protective effect on the survival of all three organisms, sustaining populations at significantly (P < or = 0.05) higher numbers over time than on corresponding unsoiled coupons. There were no significant differences (P > 0.05) among the mean number (CFU per coupon) of L. monocytogenes, Y. enterocolitica, or Salmonella on initial attachment onto the mortar surfaces (unsoiled). The results indicate relatively rapid destruction of selected pathogenic bacteria on unsoiled mortar surfaces compared with those that contained biological soil, thus highlighting the need for effective cleaning to reduce harborage of these microbes in the food factory environment.
评估了三种食源性病原体（单核细胞增生李斯特菌、小肠结肠炎耶尔森菌和沙门氏菌）附着在灰浆表面的存活情况，这些表面有或没有生物污垢（猪血清），并在有冷凝水的情况下于4℃或10℃下培养。将有污垢和无污垢的试片浸入每种菌型的五菌株混合液（约10⁷CFU/ml）中进行接种并评估。试片在25℃下培养2小时以使细胞附着，冲洗以去除未附着的细胞，并在4℃或10℃的高湿度条件下培养以在表面形成冷凝水。使用超声处理去除附着的细胞，并在120小时内的9至10个采样期测定细菌（每试片CFU）数量。在24小时内，小肠结肠炎耶尔森菌在有血清存在的情况下数量减少超过5个对数单位。在整个120小时的培养期内，单核细胞增生李斯特菌和沙门氏菌在有血清存在的情况下在灰浆上的存活情况比小肠结肠炎耶尔森菌更好。24小时后，单核细胞增生李斯特菌在10℃时的数量下降速度比在4℃时更快。总体而言，温度差异对沙门氏菌或小肠结肠炎耶尔森菌的存活没有影响。血清对所有三种生物体的存活都有保护作用，随着时间的推移，其数量维持在显著（P≤0.05）高于相应无污垢试片的水平。单核细胞增生李斯特菌、小肠结肠炎耶尔森菌或沙门氏菌最初附着在灰浆表面（无污垢）时的平均数量（每试片CFU）之间没有显著差异（P>0.05）。结果表明，与含有生物污垢的表面相比，选定的病原菌在无污垢的灰浆表面上的破坏相对较快，从而突出了有效清洁以减少食品工厂环境中这些微生物滋生的必要性。
