Eastern Regional Research Center, U.S. Dept. of Agriculture, Wyndmoor, PA 19038, USA.
J Food Sci. 2010 Aug 1;75(6):M377-82. doi: 10.1111/j.1750-3841.2010.01667.x.
Consumption of Salmonella-contaminated jalapeño peppers has been implicated in one of the largest foodborne illness outbreaks in the summer of 2008. The objective of this study was to investigate representative groups of native microflora and the distribution, growth, and inactivation of experimentally-inoculated Salmonella Saintpaul on jalapeño peppers. Two genetically modified strains of Salm. Saintpaul producing either green- or red-fluorescent protein were constructed and used in the study. Microbiological analyses showed that jalapeño peppers contained an average of 5.6 log units of total aerobic count and 3.5, 1.8, and 1.9 log units, respectively, of enterobacteriaceae, lactic acid bacteria, and yeast/mold per gram of tissue. Strains typical of Pseudomonas accounted for 8.3% of total aerobic count, and 0.2% of which exhibited pectolytic activity. On inoculated peppers, a vast majority (>90%) of Salm. Saintpaul was recovered from stem/calyx and only a small proportion recovered from fleshy pods. Growth of Salm. Saintpaul on peppers was indicated by an increase in the population of 3 log units after incubation of samples at 20 degrees C for 48 h. Fluorescent Salm. Saintpaul aggregates could be readily detected on stem/calyx using stereofluorescence imaging microscopy and scanning electron microscopy. Data presented showed that Salm. Saintpaul could survive for at least 8 wk on peppers stored at 4 degrees C. Immersion of inoculated peppers in 200 ppm of sodium hypochlorite, acidified sodium chlorite, or peroxy acetic acid for 10 min could reduce the number of Salm. Saintpaul on stem/calyx by 1.5 to 1.7 and that on flesh by 2.1 to 2.4 log units. Practical Application: Consumption of Salmonella-contaminated jalapeño peppers has been implicated in foodborne illness outbreaks. The vast majority of Salmonella Saintpaul recovered from inoculated jalapeño peppers (>90%) was from stem/calyx. Salmonella increased by 3 log units during storage at 68 degrees F (20 degrees C) for 48 h. Salmonella could survive for at least 8 wk on peppers stored at 4 degrees C. Immersion of inoculated peppers in 200 ppm of sodium hypochlorite, acidified sodium chlorite, or peroxyacetic acid for 10 min reduced Salmonella on stem/calyx by 1.5 to 1.7 log units, compared with reductions of 2.1 to 2.4 log units on flesh. These results highlight the need to consider the stem/calyx as the most likely area for contamination of jalapeño peppers, and to process this commodity accordingly to minimize exposure and cross-contaminations.
食用受沙门氏菌污染的墨西哥胡椒已被牵连到 2008 年夏季最大规模的食源性疾病爆发事件之一。本研究的目的是调查原生微生物群的代表性群体，以及实验接种的沙门氏菌圣保尔在墨西哥胡椒上的分布、生长和失活情况。构建并使用了两种产生绿色或红色荧光蛋白的遗传修饰的沙门氏菌圣保尔菌株。微生物分析表明，墨西哥胡椒组织中平均含有 5.6 个对数单位的需氧总数，分别有 3.5、1.8 和 1.9 个对数单位的肠杆菌科、乳酸菌和酵母/霉菌/真菌。占需氧总数 8.3%的是典型的假单胞菌，其中 0.2%的具有果胶分解活性。在接种的胡椒上，绝大多数 (>90%)的沙门氏菌圣保尔从茎/花萼中回收，只有一小部分从肉质豆荚中回收。在 20°C 孵育样品 48 小时后，沙门氏菌圣保尔的数量增加了 3 个对数单位，表明其在胡椒上生长。使用立体荧光成像显微镜和扫描电子显微镜可以很容易地在茎/花萼上检测到荧光沙门氏菌圣保尔聚集物。所提供的数据表明，沙门氏菌圣保尔在 4°C 下储存至少 8 周仍能存活。将接种的胡椒浸泡在 200ppm 的次氯酸钠、酸化的次氯酸钠或过氧乙酸中 10 分钟，可使茎/花萼上的沙门氏菌圣保尔数量减少 1.5 到 1.7 个对数单位，果肉上减少 2.1 到 2.4 个对数单位。实际应用：食用受沙门氏菌污染的墨西哥胡椒已被牵连到食源性疾病爆发事件中。从接种的墨西哥胡椒中回收的绝大多数沙门氏菌圣保尔（>90%）来自茎/花萼。在 68°F（20°C）下储存 48 小时，沙门氏菌增加了 3 个对数单位。沙门氏菌在 4°C 下储存至少 8 周仍能存活。将接种的胡椒浸泡在 200ppm 的次氯酸钠、酸化的次氯酸钠或过氧乙酸中 10 分钟，可使茎/花萼上的沙门氏菌减少 1.5 到 1.7 个对数单位，而果肉上的减少 2.1 到 2.4 个对数单位。这些结果强调需要将茎/花萼视为污染墨西哥胡椒的最可能区域，并相应地处理这种商品，以最大程度地减少暴露和交叉污染。
