본 실험은 산양유 casein의 조성 및 분별 그리고 이화학적 성질에 관하여 연구하고자 산양유의 일반성분을 분석하고 초유와 정상유로 산 casein을 제조하였으며 chymosin 작용과 전기영동에 의한 분리특성 및 DEAE-cellulose column chromatography에 의한 분별을 실시하였다. 그 결과, 산양 정상유의 단백질, 지방, 유당 함량은 각각 2.70${\pm}$0.27%, 3.82${\pm}$0.51% 및 4.10${\pm}$0.29%이었으며 정상유 casein보다 초유 casein에서chymosin처리에 의해 더 많은 NPN 함량이 유리되었다. 우유 및 산양유 casein을 chymosin 처리하여 전기영동을 실시한 결과 casein 조성이 서로 다르게 나타났으며 그 분리양상 또한 차이를 보였다. 산양 정상유 casein을 0.03${\sim}$0.25 M NaCl linear gradient로 DEAE-cellulose column chromatography를 실시한 결과 명확히 분별되지 않아 농도 기울기를 달리한 0.08${\sim}$0.18 M NaCl linear gradient로 column chromatography를 실시한 결과 5개의 Peak로 분리되었고 그 비율은 각각 5.27%, 26.07%, 25.97%, 30.40%및 12.29%이었다. 또한, 순수한 동정, 특히 n-casein 분획을 확인하기 위하여 chymosin을 처리한 산양 정상유 casein을 동일한 조건에서column chromatography를 실시한 결과 6개의peak로 분리되었으며 그 비율은 각각 17.06%, 9.10%, 17.85%, 20.11%, 27.03% 및 8.85%로 나타났다.

Dairy products eatable instantly have lots of nutriment, but on the other hand they are susceptible to putrefy with careless. Therefore, dairy products should be implemented the critical control points to produce both standard good qualities and hygiene ones without the contamination of hazards, because they could not been produced the perfect products only with ISO 9000 application like other industry. The application of HACCP system for dairy products produced domestically is important to certify hygiene quality and safety. It is necessary to examine regular inspection for the persistent maintenance of HACCP system. If environmental changes and improvement of manufacture facilities by expansion of new system in factory turn shift into HACCP plan, then, it is persistently accomplished the supplementation of deficiency for new hazard analysis through the periodical inspection. So far, HACCP system is mainly applied in dairy plants. If farms producing milk directly set up a sanitary plan, it can also practice sanitary control from farm to table in our country. The only dairy products produced in these conditions can be compatible to ones of other countries, they can be provided consumers over forty million with reliable foods, and contributed to the improvement of public health.

우리 나라 낙농식품산업은 어려운 여건 속에서 도 생산농가, 산업체는 물론 산학관연 둥 여러 분야의 노력에 의하여 꾸준히 발전하여 왔다. 우리 나라의 유제품소비구조는 음용유 위주로 우유 식품의 본질적 특성 상 유통기간이 짧은 것을 고려할 때 안정성 확보, 영양성분 향상, 신선도 유지 등 우유 및 유제품 품질 향상 기술 개발 및 보급은 매우 중요한 과제이다. 더욱이, 21세 기 에는 국제적으로 유제품 소비량 증가와 더불어 안전성, 품질, 선도 등 고품질 생산 공급구조로 발전되고, 생산 기 반 감소 및 환경보존 문제의 대두로 첨단기술의 개발 수요가 급증 할 것으로 예상되며, 또한 소비자가 선택할 수 있는 낙농식품의 규격, 성분표시 등의 정보수요가 확대될 것으로 전망된다. 안전하고 위생적인 우유 및 유제품의 소비확대를 위해서는 선진 외국의 기술도입과 관련연구기관간의 공동연구를 통하여 신제품개발과 품질향상 기술개발이 전개 되 어 야 한다. 결론적으로, 우리 나라 낙농식품 산업의 발전을 위해서는 탄력적인 우유 및 유제품 수급안정을 기반으로 생산효율을 증진하고 위생적이고 고품질이며 안전성이 확보된 낙농제품 개발이 중요한 과제이다.

Since generalization of cold storage of raw and processed milk, psychrotrophic bacteria has become more important. The number present in raw milk is related to sanitary conditions during pro-duction and to length and temperature of storage before pasteurization. Growth of psychrotrophs In raw milk often reduces the quality of pasteurized products. Recently, some pathogenic bacteria like Listeria monocytogenes, Yersinia enterocolitica, Bacillus cereus are reported to grow at low temperature and cause food poisoning. The presence of gram positive psychrotrophic bacteria which can survive pasteurization can limit the shelf life of pasteurized milk during extended storage and the survival of heat stable proteases and lipases produced by gram negative psychrotrophic bacteria often brings about proteolytic damage to milk protein in the products. Therefore, in order to prevent the deteorioration of milk and milk products by the growth of psychrotrophs, it is necessary to cool down the temperature of raw milk as soon as possible after milking and to keep the temperature below 5t during storage at farm. As psychrotrophic bacteria become readily predominant in raw milk under refregeration, it can be considered to change the traditional incubating temperature for SPC from 30${\sim}$32$^{\circ}C$ to 25${\sim}$27$^{\circ}C$ at which the psychrotrophs prefer to grow. The psychrotrophic bacterial count(PBC) is of limited use in dairy industry, because of the 10 days incubation period. Although estimates of psychrotrophic bacteria may provide an acceptable shelf-life prediction, there is no single, generally acceptable rapid method for replacing the PBC at the moment. Consequently, faster method for esmating psychrotrophic bacteria has to be developed.

Over decades of work, the probiotic research has grown rapidly with a number of new cultures, which is claimed a variety of benefit. However, many of the specific effects attributed to the ingestion of probiotics remain convoluted and scientifically unsubstantiated. Accordingly, the scientific community faces a greater challenge and must objectively seek cause and effect relationships for many potential and currently investigated probiotic species. Rational selection and design of probiotics remains an important challenge and will require a solid information about the physiology and genetics of candidate strains relevant to their intestinal roles, functional activities, and interaction of with other resident micro flora. As far as beneficial culture of lactic acid bacteria (LAB) is concerned, simple, cost-effective, and exact identification of candidate strains is of foremost importance among others. Until recently, the relatedness of bacterial isolates has been determined sorely by testing for one or several phenotyphic markers, using methods such as serotyping, phage-typing, biotyping, and so forth. However, there are problems in the use of many of these phenotype-based methods. In contrast, some of newer molecular typing methods involving the analysis of DNA offer many advantages over traditional techniques. These DNA-based methods have the greater discriminatory power than that of phenotypic procedures. This review focuses on the importance and the basis of molecular typing methods along with some considerations on de-sign and selection of probiotic culture for human consumption.

Consumers primarily consider flavor when they take yogurt. Recent researches on yogurt flavor productron its analytical technique have been extensively developed. These studies have provided a better understanding on the role of starter culture microorganisms on flavor formation and degradation. Yogurt volatile flavor compounds produced by the lactic cultures include acetaldehyde, diacetyl, ethanol and organic acid. Among them, acetaldehyde is recognized as a principal flavor component. since yogurt contains a delicate and low intense flavor, mild sample isolation techniques and sensitive identification means might be used. This paper attempts to discuss recent findings in yogurt flavor and to describe the application of yogurt flavor separation techniques. The section on practical aspects of culture selection based on flavor compound production and flavor analysis is also included.