Laboratory manual for physicians : aids in diagnosis and treatment.

  • New York (State). Department of Health. Division of Laboratories and Research.
Date:
1940
Catalogue details

Licence: Public Domain Mark

Credit: Laboratory manual for physicians : aids in diagnosis and treatment. Source: Wellcome Collection.

    100/108 (page 98)
    EXAMINATION OF MILK AND CREAM Samples of milk and cream are examined by the Division of Laboratories and Research only in special cooperative investiga- tions with other divisions of the Department, principally the Division of Sanitation. Health officers requesting examinations to assist in carrying out the provisions of the Sanitary Code (Chap. III, Reg. 5) are referred to a local approved laboratory. Bacteriologic examination. Before sampling, milk or cream should be thoroughly stirred with a sterile rod or by inverting the container. Samples of atleast 25 ml. should be collected through sterile glass or metal tubes of a length sufficient to reach the bottom of the original container, and transferred to screw-capped vials or glass-stoppered bottles protected against contamination and leakage. Containers should be not more than two-thirds full in order to permit adequate agitation before portions of the sample are removed for examination. Bottled milk should be submitted in the original unopened container as distributed by the dealer. All samples should be shipped to a laboratory packed in sufficient cracked ice to ensure constant refrigeration during transportation. They should be accompanied by a record of the identification marks on the original container, the name and location of the dairy, bottling plant, creamery, producer, or distributor from whom the specimen was obtained, the date and time of collection and of ship- ment, the grade, whether raw or pasteurized, the examination requested, and any other pertinent information. The standard agar-plate count provides information of -value in the routine control of the sanitary quality of a milk supply and is essential to determine compliance with the standards of grading given in the Sanitary Code. Direct microscopic examination detects unclean milk as well as that from cows with diseased udders. Since it yields valuable information concerning the bacterial and leucocyte content and may reveal the presence of flora introduced in processing, this method should be used in conjunction with the dgar count on all samples, both raw and pasteurized. The direct microscopic count is not satisfactory for the accurate grading of Certified or other grades of raw milk with low counts; marked deviations from [98]