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KMID : 1007519950040040226
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Food Science and Biotechnology
1995 Volume.4 No. 4 p.226 ~ p.230
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Acid Adaptation Promotes Survival of Bifidobacterium breve Against Environmental Stresses
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Park, Hee Kyung
SO, JAE SEONG/HEO, TAE RYEON
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Abstract
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Bifidobacterium spp. are presumed to have positive physiological effects on the human host. However, they are sensitive to acidic pH and thus would not be expected to survive storage for any length of time in the stomach and acidified dairy products such as yoghurt. Bifidobacterium spp. have to be maintained in an anaerobic condition because of the sensitivity to oxygen. In this study, we investigated whether acid adaptation would promote the survival of B. breve in subsequent acidic condition. In addition, the effects of other environmental stresses such as bile salt, hydrogen peroxide and cold storage were also examined. For acid adaptation, cultured B. breve was exposed to mild acidic condition (pH 5.2). After 60 min incubation at pH 2, the number of viable cells pretreated by acid adaptation was 100 fold higher than non adapted cells. Acid adapted cells withstood exposure to hydrogen peroxide (1,000 ppm) up to 60 min, while non acid adapted cells died rapidly. After 1 week of storage at 4℃, acid adapted cell number decreased slightly from 1.3×10^9/㎖ to 7.O×10^7/㎖, whereas non adapted cell number dropped markedly from 2.9×10^9/㎖ to 2.1×10^5/㎖. These experimental data clearly demonstrate that acid adaptation is an important survival mechanism enabling B. breve to withstand environmental stresses such as the acidic condition, bile salt, hydrogen peroxide toxicity and cold storage.
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