Investigation on survival of escherichia coli O₁₅₇: H₇ in eight kinds of food

  Objective   To investigate the survival of Escherichia coli O₁₅₇: H₇ in eight kinds of food.

  Methods   Eight kinds of food were collected and contaminated by the bacterial suspension of EHEC O₁₅₇: H₇ 933 strain, the count of contaminated bacteria was 7 log 10 cfu/ml·g. Then the survival of E.coli O₁₅₇: H₇ was observed experimentally at certain temperature(4, 25℃).

  Results   E.coli O₁₅₇: H₇ lived longer(> 70 days)in animal food than other food. The trend of bacterial survival number rose firstly and then dropped. The bacteria both proliferated 1-2 log 10 cfu/ml·g at two kinds of temperature and decreased logarithmically after reaching the peak. The bacterial count was still 3-6 log 10 cfu/ml·g after 42 days. The bacteria lived comparatively short(2-5 days in orange juice, 10-27 days in lactic drink).The bacterial count rapidly decreased to 0 when it cut down on 4 log 10 cfu/ml·g.E. coli O₁₅₇: H₇ was found intermittently in both the strawberry jam and the apple jam.

  Conclusion   E.coli O₁₅₇: H₇ had strong survival in ordinary food. The major measure to prevent and control its infection was to strengthen the sanitary administration of food, especially animal food, and beverage.