微细菌代表了微过延长保质期的乳制品中令人担忧的新兴微生物
T T Lott1, N H Martin1, J Dumpler1
1Department of Food Science, Cornell University, Ithaca, NY 14853.
Journal of dairy science
|September 7, 2023
概括
延长保质期的牛奶生产面临来自细菌生长的挑战. 这项研究发现,储存温度显著影响微生物数量,并确定微细菌是可以在制冷过程中生存和生长的关键细菌.
科学领域:
- 食品科学 食品科学 食品科学
- 微生物学 微生物学
- 乳制品技术 乳制品技术
背景情况:
- 延长保质期 (ESL) 牛奶,通常是超巴氏杀菌 (UP),面临着消费者偏好的挑战,因为与高温,短时间 (HTST) 巴氏杀菌牛奶相比,它具有"煮熟"的风味.
- 延长HTST牛奶的保质期受到心理耐受性有氧子形成细菌的限制.
- 微过 (MF) 用于减少生牛奶中的微生物,但其在不同孔径,储存温度和牛奶类型的微生物保质期方面的有效性需要进一步调查.
研究的目的:
- 研究膜毛孔大小,储存温度和牛奶类型对经过微过 (MF) 和高温短时间 (HTST) 消毒处理的牛奶微生物保质期的影响.
- 确定关键的微生物因素限制了MF-HTST加工牛奶的保质期.
主要方法:
- 原始脱脂牛奶使用0.8或1.2微米孔径微过.
- 微过的脱脂牛奶和标准化全脂牛奶都经过HTST (75°C20秒) 消毒.
- 牛奶样本在3°C,6.5°C或10°C保存长达63天,定期测量总细菌数量.
主要成果:
- 储存温度显著影响了细菌度,较高的温度 (10°C) 与较低的温度 (3°C; 3.67 log10 cfu/mL) 相比,显示出更大的细菌生长 (8.08 log10 cfu/mL).
- 在MF毛孔大小之间观察到细菌度的微小差异,而牛奶类型 (脱脂与全脂) 没有显著影响.
- 微细菌被确定为一种显著的心理耐受性,热敏性细菌,能够在MF和HTST中生存,并在制冷温度下生长.
结论:
- 储存温度是影响MF-HTST牛奶微生物保质期的关键因素.
- 虽然子是令人担忧的,但像微细菌这样的心理耐受性,热敏性细菌对在微过牛奶中实现延长保质期构成重大挑战.
- 进一步的研究应该考虑对微细菌等非子形成细菌的控制,以优化ESL牛奶产量.
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