OCTOBER, 1963 26 4!iLif Newbould and Barnum (1956) found In an experiment on the control of that a farm using a chlorine compound'' staphylococci on the udder skin, 1:5,000 for udder washing and teat cup dip­ chlorhexidine was used as an udder ping had much larger numbers of wash in one group of cows, using a staphylococci on the teat cup liners separate udder cloth for each cow, and than 2 farms which used chlorhexidine. the milking unit was flushed with run­ The farm using chlorhexidine at 400 ning water after each cow was milked. p.p.m. had an average count several In the control group, the udders were times lower than that using the same washed with water, again using a sep­ substance at 250 p.p.m. Since there arate cloth for each cow, and the milk­ , was little difference between the 3 ing unit was transferred directly with­ herds in the number of staphylococci out rinsing. being shed in the milk, these authors This combination of precautions re­ concluded that chief source of contam­ duced the number of staphylococci ination of the liners was the teat skin found on the udder surface in the ex­ and that clorhexidine was effective in perimental group to less than one­ reducing the numbers found there. eighth that in the control group. To test these hypotheses they In a further experiment, the cows changed the disinfectant used for ud­ were exposed to donor animals shed­ der washing to chlorhexidine on the ding a particular strain of staphylo­ first farm and to the chlorine com­ coccus in the milk. The donors were pound on one of the others, while leav­ milked first and the same precautions ing the teat-cup dipping procedure un­ were taken in the experimental group. changed. This was followed by a sub­ The introduced staphylococcus caused stantial and rapid fall in the number mastitis in 5 of the 9 control cows but of staphylococci on the liners of the in none of those in the experimental first farm and a rise in that on the group. As in the first experiment, liners of the second. there was a marked reduction in the Confirmation of the efficacy of chlor­ number of staphylococci on the udder hexidine as an udder wash was ob­ surface in the experimental group. tained by the present author in experi­ Thus, in these experiments, a com­ ments with monozygous twins (Re­ bination of antibacterial udder wash, ports, 1958 and 1959). The object of individual udder cloths and rinsing the these experiments was to determine milking unit with running cold water whether sufficiently rigorous hygienic after milking each cow was effective precautions at milking time would ef­ in controlling the spread of infection fectively control the transmission of and reducing the amount of mastitis. staphylococci. Davidson, Ian: Staphylococcal mastitis: its epidemiology, Veterinary Record (London), 73, 43 (1961) . Nolvasan: ( 9hlorhexidi~e) . UNIQUE AMONG DISINFECTANTS NoLVASAN is a 2% solution of chlorhexidine ( bis-p-chlorophenyldiguanidohexane), a relatively new synthetic chemical which, ,exhibits marked antibacterial activity against a wide range of gram-positive and gram-negative organisms. Bacterio­ static studies show inhibition at dilutions of 1:50,000 I 1:1,000,000. Bact~ricidal action against 99% of bacteria prese~t was complete within 5 minutes. Efficacy has been shown to persist in presence of milk, blood and other organic matter. Although it has a phenol coefficient of 500 against Micrococcus pyogenes and 5.10 against Salmonidla typhosa, both acute and chronic toxicity studies have proven it to be nontoxic to cattle when used in recommended dilutions. It does not inhibit healing of cuts, abrasions or chapped skin surfaces. In general, NoLVASAN shows greater antibacterial activity than benzalkonium chloride, a combination of a-phenyl- and p-tett-amphylphenol, and an iodine­ polyvinylpyrrolidone complex, when tested in the presence of nutrient media. It is also superior to streptomycin against Vibrio foetus and has been found more effective than either tyrothricin or acriflavine against Trichomonas foetus. NoLVASAN is available through veterinarians everywhere. It is supplied in concentrated form (for dilution of lf2 to 1 oz. per gallon of water) in 1-gallon plastic containers. Published literature on request. ·..,.An exclusive product of Fort Dodge ..I Laboratories, Fort Dodge, Iowa. Made 1 in U.S.A. by arrangement with Imperial Chemical Industries Limited. I , , i' I iFOR MORE THAN 50 YEARS ... The letters B-K have meant effec­ opment of new and improved prod­ for use. Each product has been con­ tive sanitizing to generations of ucts to meet the changing needs of veniently packaged and stamped dairymen. For more than 50 years, our industry ... to help plants and with the B-K seal of quality! more quickly, more effec­ products carrying the B-K trade­ producers In the months to come, Pennsalt's and sanitize the new­ mark have helped dairy farm and tively clean B-K Sanitation Newsletters will est, most modern types of equip­ plant managers fight bacteria, be bringing you and other indus­ bulk holding systems. protect milk quality. ment and try leaders detailed information ' Now, in these days of changing Each product has been developed on the new products developed at technology in milk production, at Pennsalt's new $9 million Tech­ the Technological Center. If you .the symbol B-K takes on new nological Center near Valley are not now receiving the News­ meaning! Why? Because Pennsalt Forge, Pa. Each product has been letter, we will be happy to put Chemicals, manufacturers of B-K thoroughly field tested for its your name on our mailing list. products, has accelerated its devel- specific application before release Write to the address below . ·' I 8-K ·department, Pennsalt Chemicals Corporation I 3 Penn Center, Philadelphia, Pa. 19102 . • ······· II • OFFICERS Journal of President, RAY A. BELKNAP, Chicago, Illinois President-Elect, jOHN H. FRITZ, Wash­ ington, ·D . C. First Vice-President, vVALLACE c. LAw­ and TON, Minneapolis, Minn. MILK FOOD Second Vice-President, FRED E. UETZ, West Englewood, N. J. Secretary-Treasu1·er, KARL K. JONES, In­ dianapolis, Ind. Executive Board TECHNOLOGY JOHN J. SHF.URING INCLUDING MILK AND FOOD SANITATION CHARLEs E. vVALToN Official Publication RAy A. BELKNAP JOHN H . FRITZ International Association of !vlilk, Food and 'WALLACE c. LAWTON Environmental Sanitarians, Inc. FRED E. UETZ REc. U. S. PAT. O FF. !CARL K. ) ONES Pub I ication Board Volume 26 October, 1963 Number 10 DR. J . c. OLSON, JR. H. L. THOMASSON KARL K. JoNES Cooling Editors Menu Items by Agitation Under Refrigeration OH. J . C. OLsON, JR., Associate Editor, Karla Longn3e, Lenora Moragne, and ]ames C. White ____ 317 Dept. Dairy Indust ri eJ~, University of Minn., St. Paul I, Minn. Status of the Preparation H . L. THOMASSON, El·ecutit:-tJ Secretary of the 12th Edition of Standard Methods and Managing EcUtor, Box 437, for the Examination of Dairy Products Shelbyville, Indiana. jOHN D . SIMPKINS, _4ssistant Ex<i'cutive F. E. Ne~on ------------ -----------------------------323 Secretary and Assistant Managi~1g Editor, Box 437, Shelbyville, Ind. Suggested Procedure for Rapid Counting of Viable Bacteria Associate Editors G. ]. ~1alecki ------------- -------- -------------------327 C . A. ABELE ______ ____ Chicago, Illinois H. S. ADAMs _____ lndianapolis, Indiana .tvl. P. BAKER------ --------Ames, Iowa Statistical Analysis of Standard Plate Counts of a Food Sample F. W. BARBER ____ New York, New York Split Among Laboratories F. C. BASELT ____ Monte Sereno, Calif. L. A. BLACK __________ Cincinnati, Ohio Harley B. Messinger - --- ------------------- ---------- -328 J. C . FLAKE __________ Chicago, Illinois L. G. HAR:~>iON ___ East Lansing, Mich. E. K. HARRrs _______ __Cincinnati, Ohio Some Observations on the Bacteriological Keeping Quality of R. P. liAYWA.lU> ___________ Bowie, Md. Milk Processed by ~igh Temperatures With a 0.6 ; C. A. HuNTER _________ Topeka, Kansas C. K. }OHNS- _Ottawa, Ontario, Canada Second Holding Time 0. W. KAuFMANN __ East Lansing, Mich. D. A. Evans, Eleanor L. Lachman and War-ren Litsky ____ 332 W. C. LAWTON ____ St. Paul, Minnesota W. S. MuELLER ______ __ Amherst, Mass. K. G. WECKEL ____ Madison, Wisconsin J. C. WmTE ________ lthaca, New York News and Events ---------------------------------------------337 The Journal of l\lll.Jr a nd l!"ood Tochnology Is Issued monthly beginning with the January Conring Events number. Each volume comprises 12 numbers. -----------------------------------------------345 Published by the Internationa l Association of Mille, l!'ood nnd Envh·onment~ l Sanitariall8, Classuied Ad -- -- --------------------------------------~------344 Inc. with exacutlve offices of thE Association, Blue Ridge Rd., P. 0 . Box 43i, Shelbyvllle, Ind. Index to Advertisers --------------------------------------------IX Entered as second class matter at the Post Office at Shelbyville, Ind., l\Iarch 1952, under the .Act on l\Iarcl1 3, 1879 .• EDITORIAL OFFICES: J. C. Olson, Jr., Business Matters : Correspondence regarding should be sent to the executh·e office of the I Associate Editor, Dept. Dairy Industries, Uni­ business matters, advertising, s ubscriJ}tions, Association, P. 0. 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