국내 유통 발효유 제품의 유산균 함량 조사

Lactic Acid Bacteria(LAB) produces lactic acid as the major metabolic end-product of carbohydrate fermentation. LAB offers health benefits such as increasing nutrients, enhancing immune system, alleviating lactose intolerance and allergy. In order to understand the characteristics of fermented milk and market trends, contents of LAB on fermented milk in Korea was investigated and isolated LAB was identified. Viable counts were performed on plate count agar with bromocresol purple(BCP) for LAB except Bifidobacterium and BS agar for Bifidobacterium. As the results, all of fermented milk in Korea contains viable LAB more than 1×10⁸ CFU/mL, Korea Food Standard for concentrated fermented milk. To identify the isolated LAB, gram stain was performed with pure culture colonies on MRS agar. Gram positive streptococci, bacilli, and variable bacilli were observed through the microscope. The isolated LAB were further identified by API CHL for lactobacilli and other LAB, by API 20A for anaerobic bacteria. As the results, Gram positive streptococci was Streptococcus thermophilus(99.2%) and variable bacilli was Bifidobacterium spp.(96.2%) isolated from sample 1-10. Gram positive bacilli was Lactobacillus rhamnosus(99.8%) isolated only sample 2.