Suspending lettuce type influences recoverability and radiation sensitivity of Escherichia coli O157:H7.

摘要: An outbreak strain of Escherichia coli O157:H7 was inoculated onto closely related but structurally distinct types lettuce (Lactuca sativa): Boston (butterhead lettuce), iceberg (crisphead and green leaf red (colored variants looseleaf lettuce). The E. either the surface cut pieces or into a homogenized suspension. Samples were gamma irradiated, radiation sensitivity bacteria expressed as D-value (the amount ionizing necessary to reduce bacterial population by 90% [kGy]). recovery from nonirradiated also measured. When surface, had significantly stronger on (D = 0.119 +/- 0.004 [standard error]) 0.123 0.003) than 0.136 0.004) 0.140 0.003). suspension, its 0.092 0.002) 0.326 0.012), 0.331 0.009), 0.339 0.010), with threefold difference. Significantly fewer recovered surfaces other examined. Following doses up 0.5 kGy, texture (maximum shear strength) leaves measured along midrib edge for each type lettuce. There no meaningful change in any section examined at dose kGy. These data show (i) that relatively subtle differences between can influence associated pathogenic (ii) kGy do not soften leaves.