Mejlholm O, Bøknaes N, Dalgaard P
Department of Seafood Research, Danish Institute for Fisheries Research (DIFRES), Lyngby, Denmark.
J Appl Microbiol. 2005;99(1):66-76. doi: 10.1111/j.1365-2672.2005.02582.x.
To evaluate the growth of Listeria monocytogenes and shelf life of cooked and peeled shrimps in modified atmosphere packaging (MAP).
Storage trials with naturally contaminated cooked and peeled MAP shrimps (Pandalus borealis) were carried out at 2, 5 and 8 degrees C. Challenge tests at the same conditions were performed after inoculation with Listeria monocytogenes. Both storage trials and challenge tests were repeated after 4 months of frozen storage (-22 degrees C). Brochothrix thermosphacta and Carnobacterium maltaromaticum were responsible for sensory spoilage of cooked and peeled MAP shrimps. In challenge tests, growth of L. monocytogenes was observed at all of the storage temperatures studied. At 5 and 8 degrees C the concentration of L. monocytogenes increased more than a 1000-fold before the product became sensory spoiled whereas this was not observed at 2 degrees C. Frozen storage had only a minor inhibiting effect on growth of L. monocytogenes in the thawed product.
To prevent L. monocytogenes becoming a safety problem, cooked and peeled MAP shrimps should be distributed at 2 degrees C and with a maximum shelf life of 20-21 d. At higher temperatures shelf life is significantly reduced.
Information is provided to establish shelf life of cooked and peeled MAP shrimps.
评估单核细胞增生李斯特菌在气调包装（MAP）熟制去壳虾中的生长情况以及此类虾的货架期。
对天然污染的气调包装熟制去壳虾（北方长额虾）在2℃、5℃和8℃下进行储存试验。接种单核细胞增生李斯特菌后在相同条件下进行挑战试验。在-22℃冷冻储存4个月后重复进行储存试验和挑战试验。嗜热栖热放线菌和麦芽香肉杆菌是气调包装熟制去壳虾感官变质的原因。在挑战试验中，在所研究的所有储存温度下均观察到单核细胞增生李斯特菌的生长。在5℃和8℃时，在产品感官变质前单核细胞增生李斯特菌的浓度增加了1000倍以上，而在2℃时未观察到这种情况。冷冻储存对解冻产品中单核细胞增生李斯特菌的生长仅有轻微抑制作用。
为防止单核细胞增生李斯特菌成为安全问题，气调包装熟制去壳虾应在2℃下配送，最长货架期为20 - 21天。在较高温度下，货架期会显著缩短。
提供了确定气调包装熟制去壳虾货架期的信息。
