Survival of Salmonella on tomatoes stored at high relative humidity, in soil, and on tomatoes in contact with soil
Survival of Salmonella on tomatoes stored at high relative humidity, in soil, and on tomatoes in contact with soil
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DOI：
10.4315/0362-028x-65.2.274
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发表时间：
2002-02-01
影响因子：
2
通讯作者：
Beuchat, LR
中科院分区：
文献类型：
--
作者：
Guo, X;Chen, JR;Beuchat, LR
沙门氏菌病与食用几种生水果和蔬菜有关，其中一些可能在收获前被沙门氏菌污染。本研究的目的是调查水和土壤作为沙门氏菌的宿主对成熟的绿色番茄果实的污染。沙门氏菌在接种的湿润土壤中至少存活了45天。在20℃下贮藏4天，接触土壤的番茄上的沙门氏菌数量增加了2.5log(10)cfu，并在以后的10天内保持不变。在20摄氏度和70%相对湿度下贮藏14天，番茄上接种的细胞数量减少了大约4log(10)cfu。在20摄氏度下，与接种土壤接触1天的水果只在皮肤表面附近或表面有沙门氏菌。随着贮藏时间的延长，西红柿茎痂和亚表层沙门氏菌细胞增多。结果表明，在接种物中的5种沙门氏菌中，蒙得维的亚沙门氏菌在接触接种土壤和现场接种的西红柿上的持久性最强，其次是坡沙门氏菌和密歇根沙门氏菌。本研究的结果表明，一种增强的绿色荧光蛋白标记可以用于检测细胞和监测沙门氏菌在其他微生物存在时的生长情况。对沙门氏菌渗入番茄组织的观察支持这样一种观点，即收获前农产品与受污染的水或土壤接触会加剧与采后病原体去除或其可用消毒剂处理有关的问题。
Salmonellosis has been linked to the, consumption of several types of raw fruits and vegetables, some of which may have been contaminated with Salmonella before harvesting. The objectives of this study were to investigate water and soil as reservoirs of Salmonella for the contamination of mature green tomato fruits. Salmonella survived for at least 45 days in inoculated moist soil. The population of Salmonella on tomatoes in contact with soil increased by 2.5 log(10) CFU per tomato during storage for 4 days at 20degreesC and remained constant for an additional 10 days. The number of cells inoculated on tomatoes decreased by approximately 4 log(10) CFU per tomato during storage for 14 days at 20degreesC and 70% relative humidity. Fruits in contact with inoculated soil for 1 day at 20degreesC harbored Salmonella only near or on the skin surface. More Salmonella cells were observed in stem scar and subsurface areas of tomatoes as the time of storage increased. PCR fingerprinting revealed that among five Salmonella serotypes in the inoculum, Salmonella Montevideo was the most persistent on tomatoes in contact with inoculated soil and on spot-inoculated tomatoes, followed by Salmonella Poona and Salmonella Michigan. The results of this study demonstrate that an enhanced green fluorescent protein marker can be used to detect cells and monitor the growth of Salmonella in the presence of other microorganisms. Observations on the infiltration of Salmonella into tomato tissues support the contention that preharvest contact of produce with contaminated water or soil exacerbates problems associated with the postharvest removal of pathogens or their accessibility to treatment with sanitizers.