大肠杆菌O157:H7在酸奶制备及4℃储存期间的存活情况

Survival of Escherichia coli O157:H7 in yoghurt during preparation and storage at 4 degrees C.

作者信息

Massa S, Altieri C, Quaranta V, De Pace R

机构信息

Istituto di Produzioni e Preparazioni Alimentari, Facoltà di Agraria, Foggia, Italy.

出版信息

Lett Appl Microbiol. 1997 May;24(5):347-50. doi: 10.1046/j.1472-765x.1997.00067.x.

DOI:10.1046/j.1472-765x.1997.00067.x

PMID:9172440

Abstract

Cow's milk was inoculated with ca 10(3) and 10(7) cfu ml-1 Escherichia coli O157:H7. After fermentation at 42 degrees C for 0-5 h, the yoghurt was stored at 4 degrees C. Two kinds of yoghurt were used: traditional yoghurt (TY), made with Streptococcus thermophilus and Lactobacillus bulgaricus starter cultures, and 'bifido' yoghurt (BY), made with the two starter cultures plus Bifidobacterium bifidum. After 7 d E. coli O157:H7 decreased from 3.52 to 2.72 log10 cfu ml-1 and from 7.08 to 5.32 log10 cfu ml-1 in TY, and from 3.49 to 2.73 log10 cfu ml-1 and from 7.38 to 5.41 log10 cfu ml-1 in BY. The pH values of yoghurt dropped from 6.6 to 4.5 and 4.4 in TY (for low and high pathogen inocula, respectively), and from 6.6 to 4.6 and 4.5 in BY (for low and high pathogen inocula, respectively).

摘要

将牛奶接种约10³和10⁷ cfu/ml的大肠杆菌O157:H7。在42℃发酵0至5小时后，酸奶在4℃下储存。使用了两种酸奶：传统酸奶（TY），由嗜热链球菌和保加利亚乳杆菌发酵剂培养物制成；“双歧”酸奶（BY），由上述两种发酵剂培养物加两歧双歧杆菌制成。7天后，在传统酸奶中，大肠杆菌O157:H7的数量从3.52 log₁₀ cfu/ml降至2.72 log₁₀ cfu/ml，从7.08 log₁₀ cfu/ml降至5.32 log₁₀ cfu/ml；在“双歧”酸奶中，大肠杆菌O157:H7的数量从3.49 log₁₀ cfu/ml降至2.73 log₁₀ cfu/ml，从7.38 log₁₀ cfu/ml降至5.41 log₁₀ cfu/ml。传统酸奶的pH值分别从6.6降至4.5（低病原体接种量）和4.4（高病原体接种量），“双歧”酸奶的pH值分别从6.6降至4.6（低病原体接种量）和4.5（高病原体接种量）。