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Effects of Cultivating Years on Survival of Culturable Escherichia coli O157:H7 in Greenhouse Soils

Yao, Zhiyuan, Zhang, Hao, Liang, Chunling, Wang, Yingzhe, Wu, Yuping
Journal of food protection 2019 v.82 no.2 pp. 226-232
Escherichia coli O157, Weibull statistics, electrical conductivity, greenhouse soils, plastic greenhouses, public health, sand fraction, total nitrogen, vegetables, China
The extent to how Escherichia coli O157:H7 can survive in soil and the predominant factors that determine its survival are crucial issues from a public health point of view. This study investigated the survival of E. coli O157:H7 in vegetable soils in plastic-greenhouse cultivation over 0, 1, 4, 8, and 12 years in southern China. Results showed that the survival times (td) calculated from the Weibull model for the five tested soils ranged from 9.00 to 21.11 days. In general, E. coli O157:H7 survived longer in open-field soils than in greenhouse soils under the same incubation conditions. The td values were greater in soils with a lower level of electrical conductivity, a higher level of total nitrogen, and a higher level of sand content. Compared to other factors, electrical conductivity was the most important factor affecting the survival of E. coli O157:H7 in the tested soils. Different survival times of E. coli O157:H7 in vegetable soils under diverse cultivation patterns highlight the importance of preventing pathogenic contamination for the purpose of food safety.