D'Souza Tanya, Karwe Mukund, Schaffner Donald W
Department of Food Science, Rutgers-The State University of New Jersey, 65 Dudley Road, New Brunswick, New Jersey 08901, USA.
J Food Prot. 2014 Oct;77(10):1664-8. doi: 10.4315/0362-028X.JFP-14-062.
Peanut butter has been associated with several large foodborne salmonellosis outbreaks. This research investigates the potential of high hydrostatic pressure processing (HPP) for inactivation of Salmonella in peanut butter of modified composition, both by modifying its water activity as well by the addition of various amounts of nisin. A cocktail of six Salmonella strains associated with peanut butter and nut-related outbreaks was used for all experiments. Different volumes of sterile distilled water were added to peanut butter to increase water activity, and different volumes of peanut oil were added to decrease water activity. Inactivation in 12% fat, light roast, partially defatted peanut flour, and peanut oil was also quantified. Nisaplin was incorporated into peanut butter at four concentrations corresponding to 2.5, 5.0, 12.5, and 25.0 ppm of pure nisin. All samples were subjected to 600 MPa for 18 min. A steady and statistically significant increase in log reduction was seen as added moisture was increased from 50 to 90%. The color of all peanut butter samples containing added moisture contents darkened after high pressure processing. The addition of peanut oil to further lower the water activity of peanut butter further reduced the effectiveness of HPP. Just over a 1-log reduction was obtained in peanut flour, while inactivation to below detection limits (2 log CFU/g) was observed in peanut oil. Nisin alone without HPP had no effect. Recovery of Salmonella after a combined nisin and HPP treatment did show increased log reduction with longer storage times. The maximum log reduction of Salmonella achieved was 1.7 log CFU/g, which was comparable to that achieved by noncycling pressure treatment alone. High pressure processing alone or with other formulation modification, including added nisin, is not a suitable technology to manage the microbiological safety of Salmonella-contaminated peanut butter.
花生酱已与几起大规模食源性沙门氏菌病暴发事件相关联。本研究调查了高静水压处理（HPP）在改性成分花生酱中灭活沙门氏菌的潜力，方法包括改变其水分活度以及添加不同量的乳链菌肽。所有实验均使用了与花生酱和坚果相关暴发事件有关的六种沙门氏菌菌株的混合物。向花生酱中添加不同体积的无菌蒸馏水以提高水分活度，并添加不同体积的花生油以降低水分活度。还对12%脂肪、浅度烘焙、部分脱脂花生粉和花生油中的灭活情况进行了量化。将Nisaplin以相当于2.5、5.0、12.5和25.0 ppm纯乳链菌肽的四种浓度掺入花生酱中。所有样品均在600 MPa下处理18分钟。随着添加水分从50%增加到90%，对数减少量稳步且有统计学意义地增加。高压处理后，所有添加了水分的花生酱样品颜色变深。添加花生油以进一步降低花生酱的水分活度，进一步降低了HPP的效果。花生粉中的沙门氏菌减少量略超过1个对数，而花生油中的沙门氏菌则被灭活至低于检测限（2 log CFU/g）。单独使用乳链菌肽而不进行HPP处理没有效果。乳链菌肽和HPP联合处理后沙门氏菌的回收率确实显示，随着储存时间延长，对数减少量增加。沙门氏菌达到的最大对数减少量为1.7 log CFU/g，与仅进行非循环压力处理所达到的减少量相当。单独进行高压处理或与其他配方改性（包括添加乳链菌肽）相结合，都不是管理受沙门氏菌污染花生酱微生物安全性的合适技术。
