非子形成的热敏细菌在同一属的菌株之间在牛奶介质中的耐热性上有很大差异
Caroline Motzer1, Martin Wiedmann1, Nicole Martin1
1Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853.
Journal of dairy science
|January 31, 2025
概括
这项研究评估了在牛奶中计算热度细菌的方法,发现使用标准方法的70°C5分钟的热处理和48小时的化可能更适合检测HTST巴氏杀菌产品中的细菌.
科学领域:
- 微生物学 微生物学
- 食品科学 食品科学 食品科学
- 乳制品科学 乳制品科学
背景情况:
- 热能细菌能够在高温下生存,影响牛奶的质量.
- 目前的实验室杀菌计数 (LPC) 测试对检测高温短时间 (HTST) 杀菌相关的细菌有局限性.
- 与形成子的类型相比,对非子形成的热敏细菌的研究缺乏.
研究的目的:
- 确定改善的实验室计数方法,用于乳制品中非子形成的热敏细菌.
- 评估不同热处理,介质和化时间的有效性,以列举热度细菌.
主要方法:
- 38个非子形成的热度细菌分离物经历了四次热处理 (30分钟的温度为63°C,15分钟的温度为65°C,7分钟的温度为68°C,5分钟的温度为70°C).
- 细菌被涂在标准方法 (SMA) 和有氧计数石化片 (AC石化片) 上.
- 盘子在32°C化24小时,48小时和72小时,结果与LPC测试进行了比较.
主要成果:
- AC Petrifilms可能会高估某些细菌种类的细胞计数减少.
- 与标准LPC方法相比,热处理D (70°C5分钟) 显示出较高的细胞数减少趋势.
- 一个48小时的潜伏期似乎足以使细菌恢复.
结论:
- 一种使用热处理D (70°C5分钟),SMA和32°C48小时化的修改方法被建议用于未来的研究.
- 这种拟议的方法可能更好地反映了与HTST处理的乳制品相关的热度细菌.
- 同一个属的分离物体之间存在热电阻的显著变异,这需要进一步的基因型研究.
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