Abstract
From his bacteriological survey on milk plants, KODAMA reported that the positive rate of coliform bacteria was in the range of from 40 to 60 per cent among the plants examined. This result, when compared with that obtained from a survey conducted on the same subject by the health centers all over Gifu Prefecture, suggests that there is much to be improved in the milk plants in this prefecture.
The authors are in the opinion that sanitary treatment of milk in the milk plant must be preceded by careful Milking and handling of raw milk. In the present survey, investigation was carried out to find out where contamination had been caused in the process of treatment in the milk plant and where high frequency of occurrence of contamination was obtained. It was the purpose of this survey to get any data available for further guidance to the improvement of facilities and handling of milk.
In the survey, changes in bacterial counts during the process in the milk plant, and presence of coliform organisms on the fingers of plant workers and in milk-bottles and paper-covers. As a result, bacterial contamination was of low degree in milk plants with well-provided facilities, while it was marked in milk plants poorly equipped. When observed from changes in bacterial counts, the contamination with and multiplication of bacteria were closely related to the cooler and other facilities located beyond it in the process. Accordingly, it was presumed that there was something wrong in the disinfection of the cooler and such machines and apparatuses as set farther than the cooler in the process of milk-plant operation.
Recently, icecream and similar products have come into popular consumption very rapidly instead of ice-candy. According to the results of tests conducted on these products by the health centers of the prefecture in the course of the year 1958, there were a large number of samples which had been condemned on account of their substandard quality.Such being the case, the authors performed examinations in factories where these products were manufactured, with regard to the environments of factories, relationship between the capacity of machines and the yield of products, arrangement of machines and apparatuses when the manufacturing process was taken into consideration, presence of coliform bacteria on the fingers of plant employees, changes in bacterial counts during each step of the manufacturing process, contamination of machines and tools with coliform organisms, and the sanitary condition of using water. These examinations were expected to give any data on the basis of which an effective guidance might be feasible. In consequence, the results obtained seemed helpful in bringing about some improvement to the sanitary conditions of the industry concerned. It is questionable that only the guidance was attributable to the better milk hygiene. Further investigation should be directed to environmental factors and arrangement of machinery, together with the effort to realize more satisfrctory facilities in plants and factories.
