Survival of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on Raw Peanut and Pecan Kernels Stored at-24, 4, and 22°C
Survival of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on Raw Peanut and Pecan Kernels Stored at-24, 4, and 22°C
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DOI：
10.4315/0362-028x.jfp-14-327
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发表时间：
2015-02-01
影响因子：
2
通讯作者：
Danyluk, Michelle D.
中科院分区：
文献类型：
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作者：
Brar, Pardeepinder K.;Proano, Lisseth G.;Danyluk, Michelle D.
采用混合细胞法测定生花生和山核桃仁表面沙门氏菌、大肠杆菌O157:H7和单核李斯特菌基因的存活情况。将4 ~ 5株菌种以3、6 log CFU/g的速度混合接种，室温干燥，-24 +/- 1、4 +/- 2、22 +/- 1℃保存28、365天。在大多数情况下，在28天的研究中，两种接种浓度之间的病原体下降率没有显着差异。在6 log CFU/g的干燥条件下，花生和山核桃的病原菌数量在最初的3天干燥期减少了0.5 ~ 1.6 log CFU/g。花生和山核桃的水分含量在-24 +/- 1和22 +/- 1℃时保持稳定；在4 +/- 2℃条件下，365天内花生的水分含量从3.8%增加到5.6%，山核桃的水分含量从2.6%增加到3%。在冷冻和冷藏条件下，山核桃上的病原菌数量稳定，但单胞乳杆菌在4 +/- 2℃下的下降速度为0.03 log CFU/g/30天，沙门氏菌在花生上的下降速度为-24 +/- 1和4 +/- 2℃，而大肠杆菌O157:117和单胞乳杆菌的下降速度为0.03 ~ 0.12 log CFU/g/30天。在22 +/- 1℃时，沙门氏菌、大肠杆菌O157:H7和单核增生乳杆菌在花生上的下降速率分别为0.22、0.37和0.59 log CFU/g/30天，在山核桃上的下降速率分别为0.15、0.34和1.17 log CFU/g/30天。在整个研究过程中，沙门氏菌计数均高于检测限（0.30 log CFU/g）。在大多数情况下，在储存期间，从山核桃中获得的计数高于花生。
Cocktails of lawn-collected cells were used to determine the survival of Salmonella, Escherichia coli O157:H7, and Listeria monocyto genes on the surface of raw peanut and pecan kernels. Kernels were inoculated with mixtures of four to five strains at 3 or 6 log CFU/g, dried at room temperature, and then stored at -24 +/- 1, 4 +/- 2, and 22 +/- 1 degrees C for 28 or 365 days. In most cases, rates of decline of the pathogens did not differ significantly between the two inoculum concentrations in the 28-day study. At 6 log CFU/g, populations of all pathogens were reduced by 0.5 to 1.6 log CFU/g during an initial 3-day drying period on both peanuts and pecans. The moisture content of peanuts and pecans remained stable at -24 +/- 1 and 22 +/- 1 degrees C; at 4 +/- 2 degrees C, the moisture content increased from 3.8 to 5.6% on peanuts and from 2.6 to 3% on pecans over 365 days. Pathogen populations were stable on pecans stored under frozen and refrigerated conditions, except for L. monocyto genes, which declined at a rate of 0.03 log CFU/g/30 days at 4 +/- 2 degrees C. Salmonella populations were stable on peanuts stored at -24 +/- 1 and 4 +/- 2 degrees C, but E. coli O157:117 and L. monocytogenes declined at rates of 0.03 to 0.12 log CFU/g/30 days. At 22 +/- 1 degrees C, Salmonella, E. coli O157:H7, and L. monocytogenes declined at a rate of 0.22, 0.37, and 0.59 log CFU/g/30 days, respectively, on peanuts, and at 0.15, 0.34, and 1.17 log CFU/g/30 days, respectively, on pecans. Salmonella counts were above the limit of detection (0.30 log CFU/g) throughout the study. In most cases during storage, counts obtained from pecans were higher than from peanuts.