The Food Safety Modernization Act (FSMA) includes a time-to-harvest interval following the application of noncompliant water to preharvest produce to allow for microbial die-off. However, additional scientific evidence is needed to support this rule. This study aimed to determine the impact of weather on the die-off rate of Escherichia coli and Salmonella on spinach and lettuce under field conditions. Standardized, replicated field trials were conducted in California, New York, and Spain over 2 years. Baby spinach and lettuce were grown and inoculated with an ∼10⁴-CFU/ml cocktail of E. coli and attenuated Salmonella. Leaf samples were collected at 7 time points (0 to 96 h) following inoculation; E. coli and Salmonella were enumerated. The associations of die-off with study design factors (location, produce type, and bacteria) and weather were assessed using log-linear and biphasic segmented log-linear regression. A segmented log-linear model best fit die-off on inoculated leaves in most cases, with a greater variation in the segment 1 die-off rate across trials (−0.46 [95% confidence interval {95% CI}, −0.52, −0.41] to −6.99 [95% CI, −7.38, −6.59] log₁₀ die-off/day) than in the segment 2 die-off rate (0.28 [95% CI, −0.20, 0.77] to −1.00 [95% CI, −1.16, −0.85] log₁₀ die-off/day). A lower relative humidity was associated with a faster segment 1 die-off and an earlier breakpoint (the time when segment 1 die-off rate switches to the segment 2 rate). Relative humidity was also found to be associated with whether die-off would comply with FSMA’s specified die-off rate of −0.5 log₁₀ die-off/day.

中文翻译：

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天气对污水和污染的灌溉后大肠埃希氏沙门氏菌减毒鼠伤寒沙门氏菌死亡的影响。

《食品安全现代化法案》（FSMA）包括在不合格的水用于预收获产品以允许微生物死亡之前的收获时间间隔。但是，还需要其他科学证据来支持该规则。这项研究旨在确定天气对田间条件下菠菜和生菜的大肠杆菌和沙门氏菌死亡率的影响。过去两年，在加利福尼亚，纽约和西班牙进行了标准化的重复田间试验。生长菠菜和生菜，并接种约10 ⁴ -CFU / ml的大肠杆菌和减毒沙门氏菌混合物。接种后的7个时间点（0至96小时）收集叶片样品。列举了大肠杆菌和沙门氏菌。使用对数线性和双相分段对数线性回归评估死亡与研究设计因素（位置，产品类型和细菌）和天气的关系。在大多数情况下，分段对数线性模型最适合于接种叶片的死亡，各试验中第1部分的死亡率差异更大（-0.46 [95％置信区间{95％CI}，-0.52，- 0.41]至-6.99 [95％CI，-7.38，-6.59] log ₁₀每天的消亡率比段2的消亡率（0.28 [95％CI，-0.20，0.77]至-1.00 [95] ％CI，-1.16，-0.85] log ₁₀每天死亡）。较低的相对湿度与段1的更快死亡和更早的断点（段1的消失率切换为段2的时间）相关。还发现相对湿度与模切是否符合FSMA规定的模切率-0.5 log ₁₀模切/天有关。