Laboratory of Food Microbiology and Food Preservation, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
Int J Food Microbiol. 2010 Feb 28;137(2-3):147-53. doi: 10.1016/j.ijfoodmicro.2009.11.013. Epub 2009 Dec 3.
The survival of Campylobacter spp. under defined conditions of freezing (-22 degrees C) was studied in naturally contaminated chicken skin and minced chicken meat. A decline of approximately one log(10) cfu/g was observed after 1 day of freezing. No further significant reduction was achieved by prolonged storage in the freezer, although a tendency for further gradual reduction of the numbers of Campylobacter spp. present was noted. Campylobacter spp. could still be detected qualitatively (per 0.1g) after 84 days. In a second part of this study, the survival of Campylobacter spp. in a typical minced meat preparation (minced meat supplemented with 1.5% salt (NaCl)) stored at refrigeration (4 degrees C) or frozen (-22 degrees C) was studied. No significant reduction of the pathogen was observed if the minced chicken meat was kept at 4 degrees C for 14 days, opposite to approximately one log(10) cfu/g reduction after 1 day when the minced meat preparation was stored in the freezer (-22 degrees C) for 14 days. The latter reduction is imputed to the effect of freezing as mentioned above and not due to the supplementation of NaCl to minced meat or the combination of NaCl and freezing, because similar reductions of Campylobacter spp. were noticed when minced meat (without addition of NaCl) was frozen. Finally, in a third part of the study, the survival of Campylobacter spp. subjected to a heat treatment, conform to consumer-based pan-frying, in inoculated (4.5+/-0.2 cfu/g) as well as naturally contaminated chicken burgers (2.1+/-0.1 cfu/g) was studied. The Campylobacter spp. numbers declined after 2 min (internal temperature reached circa 38 degrees C), where after 4 min (internal temperature reached circa 57.5 degrees C) they dropped below detectable levels (<10 cfu/g).
研究了在自然污染的鸡皮和鸡肉碎中，弯曲菌属在冷冻（-22℃）条件下的存活情况。冷冻 1 天后，观察到大约减少了一个对数（10）cfu/g。尽管存在进一步逐渐减少的趋势，但在冷冻器中长时间储存并没有进一步显著降低。在 84 天后，仍然可以定性检测到弯曲菌属（每 0.1g）。在本研究的第二部分中，研究了在典型的鸡肉碎制备（鸡肉碎中添加 1.5%盐（NaCl））中，在冷藏（4℃）或冷冻（-22℃）下储存时，弯曲菌属的存活情况。如果鸡肉碎在 4℃下储存 14 天，不会观察到病原体的显著减少，而相反，如果鸡肉碎制备在冷冻器中（-22℃）储存 14 天，则会观察到大约一个对数（10）cfu/g 的减少。后一种减少归因于上文提到的冷冻效应，而不是由于 NaCl 添加到鸡肉碎中或 NaCl 和冷冻的组合，因为当没有添加 NaCl 的鸡肉碎冷冻时，也观察到类似的弯曲菌属减少。最后，在研究的第三部分中，研究了经过消费者基础的煎炒热处理后，接种（4.5+/-0.2 cfu/g）和自然污染的鸡肉汉堡（2.1+/-0.1 cfu/g）中弯曲菌属的存活情况。在 2 分钟（内部温度达到约 38℃）后，弯曲菌属数量下降，4 分钟（内部温度达到约 57.5℃）后，数量降至可检测水平以下（<10 cfu/g）。
