Modeling the impact of chlorine on the behavior of Listeria monocytogenes on ready-to-eat meats.
Modeling the impact of chlorine on the behavior of Listeria monocytogenes on ready-to-eat meats.
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DOI：
10.1016/j.fm.2011.01.001
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发表时间：
2011-08
影响因子：
5.3
通讯作者：
S. Sheen;C. Hwang;V. Juneja
中科院分区：
文献类型：
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作者：
S. Sheen;C. Hwang;V. Juneja
由于潜在的交叉污染，单核细胞增生李斯特菌（Lm）继续对即食（RTE）肉类造成食品安全危害。氯通常用于消毒加工设备和器具。然而，Lm可能在处理后存活，然后污染食品。本研究的目的是表征氯暴露的Lm的行为在RTE火腿冷藏期间。将Lm血清型4 b的两种菌株混合物用氯（0、25和50 ppm）预处理1小时，然后接种到RTE火腿的表面上以获得约3.0 log CFU/g的接种物。将接种的火腿样品储存在4、8和16 °C下，并在储存期间定期计数Lm。使用DMFit软件估计Lm的生长特性（滞后时间和生长速率）。结果表明，氯处理抑制了Lm的生长。在4 °C下，没有（0 ppm）氯暴露的Lm的滞后时间（4.2天）比暴露于25 ppm（5.4天）和50 ppm（6.8天）的Lm的滞后时间短。滞后时间随温度的升高而减小，在25 ppm时，4、8和16 ℃下的滞后时间分别为5.2、3.8和2.6天，并且随着氯浓度的增加而增加，例如，在16 °C下，0、25和50 ppm的滞后时间分别为1.2、2.6和4.0天。生长速率随温度的升高而增大，随氯浓度的增加而减小。滞后时间和生长速率作为氯浓度和温度的函数可以分别使用修改的Ratkowsky模型和修改的Zwietering模型来描述。结果表明，预先暴露于氯（≤50 ppm）会延迟即食火腿上Lm的生长。所建立的预测模型将有助于即食肉的微生物风险评估。
Listeria monocytogenes (Lm) continues to pose a food safety hazard in ready-to-eat (RTE) meats due to potential cross-contamination. Chlorine is commonly used to sanitize processing equipment and utensils. However, Lm may survive the treatment and then contaminate food products. The objective of this study was to characterize the behavior of chlorine-exposed Lm on RTE ham during refrigerated storage. A two strain cocktail of Lm serotype 4b was pre-treated with chlorine (0, 25, and 50 ppm) for one hour, and then inoculated onto the surface of RTE ham to obtain an inoculum of about 3.0 log CFU/g. The inoculated ham samples were stored at 4, 8, and 16 °C, and Lm was enumerated periodically during the storage. The growth characteristics (lag time and growth rate) of Lm were estimated using the DMFit software. The results indicated that Lm growth was suppressed by the chlorine treatment. At 4 °C, the lag time of Lm with no (0 ppm) chlorine exposure (4.2 days) was shorter than those exposed to 25 ppm (5.4 days) and 50 ppm (6.8 days). The lag time decreased with the increase of temperature, e.g., at 25 ppm, the lag times were 5.2, 3.8 and 2.6 days for 4, 8 and 16 °C, respectively, and increased with the increase of chlorine concentration, e.g., at 16 °C, the lag times were 1.2, 2.6 and 4.0 days for 0, 25 and 50 ppm, respectively. However, growth rate increased with the increase of temperature and decreased with the increase of chlorine concentration. The lag time and growth rate as a function of chlorine concentration and temperature can be described using a modified Ratkowsky model and a modified Zwietering model, respectively. The results showed that the growth of Lm on RTE ham was delayed by pre-exposure to chlorine (at ≤50 ppm). The predictive models developed will contribute to microbial risk assessments of RTE meats.