JOURNAL of MILK TECHNOLOGY

I Volume 2 July, 1939 Number 4

Editorials ifhe opinions and ideas expt·essed in papers and editorials are those of the respe

Public Recognition of Achievements in Improved Milk Sanitation It is generally recognized that we can be so close to a situation that we fail to recognize great achievements in the making. As we view the field of milk sanita­ tion as it exists today, and then in retrospect look at the situation as it was ten to fifteen years ago, we become aware of the distance that we have traveled in the im­ provement of milk sanitary practices. These accomplishments have been the result of two lines of development. One of these has come through the sma.ll but frequent contributions of sanitarians in their diily routine of supervisory duties. "Precept upon precept; . . . . line upon line; here a litde, there a little." Conscientious, enthusiastic, and intelligent milk inspec­ tion cannot help but occasionally lead to an improvement in some practice of milk handling in the district of the faithful sanitarian. The sum total of. all these minor steps build_s up a body of knowledge which is large in the aggregate. The other line of advance comes through the outstanding achievements of in­ dividual sanitarians. The field of milk sanitation and technology, likel all other lines of human endeavor, is fertile with the possibilities of discovery and development by individuals with adequate training, initiative, and vision. .Wh'at are some of these outstanding accomplishments? In the early days of milk inspection and the inauguration of the program for the radication of bovine tuberculosis, who ever thought that we should achieve anything more than numerous modified accredited areas? Some one had the vision and the persistence to keep the program alive. Try to visualize milk inspection without the aid of the direct microscopic examin­ ination. This one technic has probably exerted more influence in the improvement of milk quality than all other milk supply inspection procedures combined. Its value alone warrants all the appropriations expended by the State of New York for the Ctneva Experiment Station-although the latter has made many other contributions m numerous fields. . Some of us recall the time when there was no general recognition that there ' txtsted a field for dairy engineering other than what then obtained. A tank was a l111k; a p i ~e that could be dismantled rather easily was generally satisfactory; a valve that looked clean and that was demountable was accepted. Continuity in milk pasteur­ ceases to be seen (and useful) after the ceremony of its award. The monetary part, ization was limited to multiple batch installations. Foam was considered like death possibly contributed by a foundation or industrial organization in the interest of public and taxes. Look at the situation now. How did it come about? One man had the benefaction, would impart intrinsic value and substance. ability and energy to examine critically his supervisory responsibilities, saw the me­ Therefore, the International Association of Milk Sanitarians can do well to chanical deficiencies of equipment, and showed how they could be corrected. He consider the establishment of an award for achievement in milk sanitation and allied created a new field of milk engineering. technology. This undertaking would both honor the recipient and publicize an im­ For years, we have depended on proper installation, the temperature-time charts portant item in sound gov~r~mental function. It would ~fford an excellent oppor­ on pasteurizers, and the apparent intelligence and p resumable integrity of the operato J> tunity to educate the pubhc m a necessary phase of pubhc health, and also would to pasteurize milk safely. A given bottle of milk, labeled as pasteurized, was hoped to strengthen milk inspection wherever the news is broadcast, especially in the terri­ be safe because previous bottles had been so (and several days hence we may k!!_O W> tory where the meeting is held. Peace has its victories no less than war, and we that this bottle is safe also). Now, we can examine the milk from this battle, and; could do well to honor our notables. know in a few hours whether it had been properly pasteurized. How did we get J. H. S. such a tool? A chemist, working in a dairy laboratory on a "high brow" problem o~ milk composition, had the ability to see the unexpected value of a by-product of l:gs research. So he obtained the phosphatase test for the detection- of improperly PW· cessed milk. The Bacteriology of High-Short Pasteurization As we used to look over great areas of our country, we have regretted the lallk: The bactericidal e_f:fectiveness of a CO'mmercial installation of a high temperature­ of effective milk quality supervision, with the attendant low per capita milk con. short time pasteurizer (called herein high-short) has recently been reported in detail sumption. This has changed. One man saw a need-and acted. So developed ,the by Dotterrer ( 1). His data on two hundred samples of milk over a period of nine Public Health Milk Ordinance with its effective and influential program of improv.ed days shows a tpercentage decrease of bacteria colonies by the plate technic of 96.84 sanitation, technology, and education. when the milk is held 30 minutes (presumably at 144° F.) as compared with a de­ Why does one state have all the septic sore throat in the country? One man i-f crease of 93 .31 by the high-short process. Dotterrer elsewhere states that "some pondering on what he observes, and is making significant discoveries in etiology and organisms would be classed as heat resistant to short time pasteurization but not to 30 diagnosis of several serious milk-borne diseases. minute pasteurization," and points out that thermoduric organisms must be elimi­ Abortion and undulant fever-some one showed the relation and the hazard. nated from the raw milk if bacterial counts by the high-short method are to be com­ parable to those by 30 minute holding pasteurization : (herein called low-long). Shall we only just go ahead occupying ourselves as usual and applying f.reely Eurthermore, he states that " . . . . the margin of safety would seem to be less in short the technics and the knowledge unselfishly developed by various outstanding conlilllb­ time pasteurization than in the case of 30 minute holding . . . . " utors? These latter do not think about any reward. They giv~ their data fre~y, co the world. ·• ,· · Krueger (2) when reporting on the Chicago studies in high-short as compared with low-long pasteurization (presumably including much of the work reported above In spite of professional and personal modesty, every person 'likes to be appnet!i­ in more detail by Dotterrer) states that " . . .. high counts might occur at any time ated by his fellows. Conventionally, this takes the form of granting an award fur without notice and disappear as rapidly," and also " ... . high counts were found outstanding accomplishments in some defined field. We conte.n9 that there is no either ~sting momentarily or persisting for longer periods of time." Krueger and field where personal achievements are more worthy of publi~cognit.ion tharu ~he Dofferrer both agree that thermoduric organisms are sometimes found in low-long one of milk sanitation. processing, and that cleaning up the raw supply eliminates them. But personal acclaim is not all that is involved. The public granting of a J?!O· Two possible explanations for these phenomena present themselves to us. The fessional award to an accomplished "medalist" exercises an influence on the common first one is a purely physical one. It might be that the . sampling in the high-short weal that is noteworthy. The very fact that a person is so honored constitutes ne-ws. process picks up mitk that has not been well mixed and therefore exhibits the quality The ceremony itself is performed under circumstances of dignity and more o~ le.» of individual cans of milk carrying a preponderant thermoduric flora . On the other pageantry, all of which attracts attentio~. These are featured_ in the ~rofessiol).aU and hand, samples of low-long milk are always taken from large batches where the milk of daily news press. The event emphastzes what the profeSSIOn constders to oe the individual cans is so mixed with milk from many sources that a thermoduric flora "newer knowledge" in this field. It brings forcibly to general attention an outstaod from a few farms will be distributed throughout the whole batch without revealing its ing development which otherwise the public mi$ht never know _about. It earmar~, character. so to speak, that which has been fotmd to be Important, effective and saleable-m The other explanation for the irregular finding of high counts is the one offered general, practical. by Dotterrer and earlier by Mattick (see below), namely, that the bacteriological With regard to ways and means for implementing these considerations, opinio~ margin of safety for the high-short process is not as great as that for the low-long may differ. We might suggest that the recipient of the award should be one :who!~ treatment, and that some types of organisms may be thermoduric to one of these pro­ nominated by the Executive Committee of the International Association of Milll: Sam· ~esses but not to the other. His remedy is to locate all such milk supplies and elim­ tarians. The actual form of the award might consist of an engrossed appreciatio~, to mate this flora. gether with a monetary h.onorarium. The state~ef!t can be framed to gi~e a c;ootJRud This second explanation raises a very serious question, namely: Are all the ous service on the wall m the office of the reCipient whereas a medal ts cased an pathogenic types of organisms found in milk heat-sensitive to high-short pasteuriza- 160 EDITORIALS

tion? Are we to expect that some pathogens may be thermoduric to the high-short The mechanical engineering of high-short pasteurization has progressed faster process that are not so resistant to the low-long treatment? than our knowledge of the fundamental bacteriology concerned. It is possible that Much information is available to indicate that the present specification of heat­ also the chemistry of milk so treated could be elucidated. A balanced technology ing at a temperature of 160° F. for 15 seconds is bactericidal for most of the organ­ needs all three sciences. Our knowledge of those involved in high-short pasteuriza­ isms commonly encountered. The Committee on Milk Supply of the Engineering tion is not well established. Section of the American Public Health Association and the Committee on MillC ( 1) High temperature short time pasteurization. W . D. Dotterrer. Papers Presented at Dairy Manufacturers' Conference, March 14-16, 1939, University of Wisconsin Madison Sanitation of the Conference of State Sanitary Engineers (3) have listed several Wis. See f . Milk Tech. this issue, p. 197. ' ' investigations which reported the bactericidal effectiveness of high-short pasteuriza­ (2) The introduction into Chicago of the high-temperature short-time method of milk pasteur­ tion (although the details of this bacteriological work are not available in publ~ca­ ization. P. F. Krueger. J. Milk Tech. 1, No. 7, 29 (1938)_ tions) . The workers in Chicago and also Kay and Neave (4) report that pathogenic (3) High-temperature short-time pasteurization. Mimeographed pamphlet, 1931. U. S. Public Health Service, Washington, D. C. microorganisms are destroyed before the enzyme phosphatase. . Kay (5) states that ( 4) Some results of the application of a simple test for efficiency of pasteurization. H . D. Kay phosphatase is less readily destroyed by ?eat than M. tubercttlosrs_, and th~t the enzyme and F. K. Neave. Lancet 1, 1516 (1935). is just completely destroyed by the mmtmum temperature and ttme requtred for legal (5) Control of the efficiency of pasteurization of milk: the phosphatase test. H. D. Kay. pasteurization in Great Britain, namely, 145 o F. for 30 minutes. Can. Pab. Health f. 27, 551-4 (1936); Chern. Abs. JI, 2302 (1937). (6) High temperature short time pasteurization. A. R. T. Mattick and E. N . Hiscox_ Inter­ Mattick and Hiscox ( 6) had previously obtained results very similar to those nat. Dairy Congress; lOth. Rome-Milan, 1937, 124-III, p. 199. reported by Dotterrer. They. compared the. bacterial reducti~n of ~il~ _pasteurized (7) High temperature short time pasteurization by the Aluminum Plant and Vessel Company·~ by holding in the laboratory wtth th~~ pasteunzed by a com~ewal Sta~smtzmg pasteur­ Plate Machine.·Experiments on the destruction of tubercle bacilli and streptococci. A R. T. Mattick. Nat. Inst. Res . Dairying, 1937. izer. They state: "The correspondmg figure for the milk pasteunzed by the Jab­ (8) High-temperature short-time holding pasteurization in the United States. M. W. Yale. oratory holder process shows that the reduction accomplished by the machine was 26th Ann. Conv. bztemat. Assoc Milk Deale,·J, Lab. Sec., 1933. not the maximum possible. In general, it se~ms _that, in spite of the ~ost pre~sc (9) Resistan& of non-spore-forming bacteria to heat. P. R. Beamer and F. W. Tanner. control, the margin of safety is too small to mspu·e confidence. Orgamsms which Zentr. Bakt. Parasitenk. Infek. II. Abt. 100, 81-98 ( 1939). (10) Heat penetration in processing canned foods. W_ D. Bigelow, G. S. Bohart, A. C. Rich­ have some degree of heat resistance, . without being. thermod~ric if,l the accept:d sense, ardson, and C. 0 . Ball Nat Canners' Assoc. Bul. 16-L, 1920. clearly ·escape destruction, and they appear to constitute a fatrly htgh proportiOn of an Mathematical solution of problems on thermal processing of canned food. C. 0. Ball. ordinary milk flora." Univ. of Calif. Pub!. in Pub. Health I, 15 ( 1928). ]. H. S. Mattick reports (7) that holding at 160° F. for 15 seconds or at 164o F. without holding killed all tubercle bacilli and hemolytic streptococci. In the 1936 Annual Report of the National Institute for Research in Dairying, it is stated that the pasteur. Missouri Association of Milk Sanitarians ization of milk in the A. P. V. plate pasteurizer at 162 ° F. ~o,r,_ 1"5 seconds, and m It is with great satisfaction that we welcome the Missouri Association of Milk the Stassinizer at 165 o to 166 • F., under commercial conditiobs; revealed that Both Sanitarians into the family of organizations which have designated the JOURNAL machines showed an efficiency practically equal to that of pasteurization at 145 o F. for 0F MILK TECHNOLOGY as their official organ. We recall how sanitary en­ 30 minutes in the laboratory. We know that in commercial operations pasteuriza. gineers from this state showed that important aspects of milk plant equipment, con­ tion by the long holding process is more bactericidal than laborato~y pasteurization in sidered. !,tp to that time perfectly satisfactory, were really faulty in design and opera­ a test tube. Therefore, the above high-short data, if only equal"'t'o laboratory pasteur· tion, and needed correction. We hope and expect that this new affiliation of kindred ization, must not be as effective as commercial low-long pasteurization. interests will further stimulate all milk sanitarians to examine critically their daily An excellent review of the relative performance of high-short and low-long round of activities and ascertain whether they are neglecting important items, here­ .pasteurization on the bacterial and organoleptic quality of milk was published by tofore too familiar to be noticed. Missourians joltea us :into an increased super- Yale in 1933 (8). There is general agreement among investigators that ali patl:'iogens visory alertness. We hope that they will do it again. J. H. S. arc killed (or inactivated) in both processes and that standard plate colony counts do I I not regularly run as low in milk from the sho_rt treatme~t. as in that _from the long ont. No information is available as to the relattve bactenctdal effecttv·eness of the two The Pennsylvania Association of Dairy Sanitarians processes from the quantitative standpoint. . The recent action of the Pennsylvania Association of Dairy Sanitarians in desig­ It would seem that our knowledge _of the bacteriology involved is capaple of natmg the JOURNAL OF MILK TECHNOLOGY as their official organ greatly much greater development. A recent paper by Beamer and Tanner (9) indicates that ltrengthens the field of milk sanitation. Their membership includes nam-es long the thermal death curves of non-spore-forming bacteria are as amenable to mathemal· k_nown :vell in this work-names of men who have pioneered in helping to make pas­ ·I ical expression as those of spore-formers, so admirably demonstrated by Bigelow, B~l~ Sib!~ thts increasingly bright day of recognition of the importance of milk sanitation. and their associates ( 10) . We are impressed with the relative meagerness o£ our JR Santtarr engineering, dairy technology, and milk quality control, under both official formation concerning the detailed bacteriology of high-short pasteurization. Careful lnd prtvate auspices, have received strong emphasis in this great state. This influence studies of the bacteriological aspects should be conducted with the finesse that would has been widely felt. As the International Association of Milk Sanitarians further I render the work susceptible to mathematical expression. They should be of de:velops its program of improved milk quality, it welcomes this new affiliation with broad and fundamental significance that they might well serve as an adequate < fmma~> :s OUt K:eystone associates. The increased inspiration and strength afforded may be tion on which to build a sound milk-processing technology. cxpeeted to yield good dividends in the public interest. J. H. S. JOURNAL OF MILK T ECHNOLOGY 163 'I

a vlell known Chicag?. man u fa c tu ~ er with emphasis placed upon the import­ . cleaners and stenllzers, a senes ance of cooling. No doubt, Detroit's da.Ir~ gs over our milk shed. We held program in relation to this went over Educational Methods in Relation meetul meetings m. areas w here many much easier than would have been the to Milk Sanitation * lived. The general attendance case had no attempt been made to am­ :l ttJrodlliC"' IF~ encouraging. The farmers' plify and explain the new regulation. H. S. Adams ~,Were invited, the plants supplied In the southwestern part of Michigan Department of Health, Flint, Michigan...... and a representative of the a plan was developed in cooperation with ere ...... , 1· ·1k e showed a film on qua tty ill! the W . K. Kellog Foundation Units and The purpose of this paper is to present _,.,u,..... , Our attendance was over local veterinarians. Realizing that the certain types of educational methods and it was felt that conside~able veterinarian is an influential person in which have been found valuable and ef­ Was derived from these meetmgs. the community as far as molding the view­ fective in milk control work. A casual Iue d , . 51'rnilar series of pro ucers meetmgs points of farmers is concerned, a plan analysis of the problem indicates that milk 1so· been held in the Lansing, Michi- was evolved to enlist the cooperation of Jps a 1 d' . . sanitarians have to deal with at least four mi)k shed. County or tstnct umts this group. In addition, this plan was 0 distinct units or groups: the milk pro­ ' attern after this plan on a s~aller developed to render service to dairymen ducer, the milk hauler, the plant operator 0 1 p and by enlisting the cooperatiOn of for controlling and eliminating mastitis and his employees, and finally the con­ the eplants, meetings for their producers from dairy herds. This type of educa­ suming public. There is, quite obviously, an bemeld. An elaborate program _does tional approach depends upon the ability still another very important group which 001 have to be a rra~ged. ~ talk tllus­ of an organization to enlist, partly most certainly cannot he overlooked, EDUCATION OF PRODUCERs rr,ated ;with stereopttcon sltdes can be through subsidy, the cooperation of a namely, milk control officials themselves. In an effort to determine what I,'ILlde !Valuable. A set of a dozen or so profession already doing work in the and methods other health p 1 cture~ . or a fil m ~trip, illus~:ating sani­ field.. Apparently, however, the plan EDUCATION OF INSPECTOR and inspectors have found to lU}' methods of mdk productiOn, can ~e was not considered feasible since after The first and foremost group to keep educational toofs, I sent quesno11na1 obt~ined, or yo u can make your own tf approximately. two years operation, that in constant touch with new developments one hundred and twenty-five u plan in ad vance procedmes you want part of the program dealing with the ex­ and technics in milk control work is the gaged in public health to illustrate. Many state colleges have amination of cattle for mastitis was inspector himself. Many states have as­ throughout the count~:y. . me very good slides, and these, I am dropped. However, this brings up an ceived indicated 'that few I sociations such as ours, notably Calif­ re, q10 be obtained on loan for special important point, veterinarians can be very ornia and New York, where stimulating have a definite, planned ~-'"'"La..t.u meetings. helpful allies. If they understand the r and informative programs are arranged ganized producer education. Demonstrations offer another valuable policy of the Health Department in its and two or three day conferences held. did depended for the most ool. The Detroit Health Department, program to improve milk sanitation, their II The program for the 1938 Regional sending periodic ne~~ letters ut lhree yea rs ago, enlisted the assist­ opinions, when voiced to the dairymen, I Training School for Dairy and Milk In­ and the distribution of mce of the Agricultural Engineering De­ become a valuable asset to the milk sani­ spectors of New York State is a three­ material. Many who partment, at Michigan State College, and tarian. I! day conference giving comprehensive they felt that information n exhibit was provided to show proper A rather· novel type of producer educa­ consideration to many phases of milk terpretation of regulations and methods and details for providing insu­ tion with which some may be acquainted I sanitation from the time the milk leaves governing the production of lated milk cooling tanks. A cut-away was adopted by the Baltimore City Health I the cow until it reaches the consumer. be considered educational in model of a cooling tank was provided to Department a few years ago, and since Included in the course is a thorough dis­ opinion was expressed, and justlllall> lr.! show the correct procedure for installing found to be extremely effective. Under cussion of laboratory procedures. that personal contact was of Jnsulation. Two men accompanied the this plan, inspectors established demon­ importance in producer education. Mr. C. Sidney Leete, of the New York ibit, one gave a talk on factors of stration herds throughout the milk shed. With regard to personal contact, Department of Health, makes this com­ mportance in the production of quality Milk producers in the vicinity of these ·ever, many of us are faced, ment of significance: milk, the other discussed details for the herds were requested to at tend, and the in larger communities, with limited (OOstruction of cooling tanks with in­ inspectors then proceeded to go through "We believe that the education and train­ sonnel. Consistent personal contact ing of the various local milk inspectors is a iUlation correct! y installed. the exact steps necessary for the proper function which will produce lasting results in­ producers under such 'rrn m~lf'an t~ 1 This acco mplished two things. First, production of high quality milk as re­ sofar as milk sanitation is concerned. In co­ beyond the realm of possibilitr­ ll gave positive assurance to the producer quired by the Baltimore Ordinance. To operation with other agencies of the state we fore, a mass educational approaeh supplement the demonstrations, the are conducting three-day milk inspectors' at the Health Department wanted to be the most logical one to follow. of service so that the tank he was about Health Department published a very com­ bilities are open through several provide would be acceptable. Second, prehensive bulletin, profusely illustrated, • Presented at. the March, 1939, meeting of the to Michigan Mtlk Inspectors' Association, Detroit, nels. In Flint last summer we offered an opportunity to mention for producers to study. Although some­ Michigan. in cooperation with our milk p.)ants f. ors of importance in milk production what time-consuming, I am certain that 164 bDUCATION IN SANITATION

this is a very effective means of producer be of great aid and will make a tall!: b.ilis and its c?ntrol. . We have Any one could enlist the cooperation of education. more effective. ~Y[ d this instructiOn penod to sub­ college authorities or the College Exten­ This ·plan calls to mind the possibility IS e semi-annual physical examina- sion Service, and hold at least two or a . d of using some of our own resources along EDUCATION OF MILK HAULBB. 'ch was formerly requtre . three meetings over a period of time as \V hI this line. While in county work, I had AND HANDLERS convenient. If such a program can be hoped to try it, in fact did get to the ION OF PLANT OPERATORS successful in Lansing, it can also be The milk hauler sees the souCA T point where the county 4-H Club lead~r nearly every day and often worthwhile and valuable in other com­ and I discussed it. I refer to the feasi­ st general training progra.m of mumttes. One other point that must not news of the milk plant or of mo and employees IS one bility of using a team of two or three be overlooked is this: the milk inspector, department. Every reasonable on the Lansing Hea!th De~art- boys each to conduct demonstratiOns at himself derives considerable benefit from should be extended to these iuu•,v•n·"·" Th plan seems to ment attentiOn, selected brms to show producers in the these g~therings. "W_e can be justly crit­ When literature and anno .... .,coJJrnn rom 4.5 to 65 at each meeting. Some of partment, that he has rec7ntly prep~red in Flint, during the last ten months, be subjects discussed were as follows: ager, the operator, or both. Do not for­ a motion picture film on m1lk production. instruction period for food and '··•itis Bang's Disease, Off-Flavors of get the other employees, as well. It is a ,Po)l J • good practice occasionally to get their The March of Time film, "The U. S. handlers. Attendance is LU>luu'U".ur• k, J:b~ Health and D1sease of the Milky Way" has a high degree of gen­ fore a so-called "foot!- handlors' d loiTndler, Consideration of Labora­ slant on general procedures. Many times eral popular interest and appeal for the card" is .issued. Two sessions are TeChhics, and a session dealing with they will ask a question which may bring producer, the dealer, .and the pu~lic. Ef­ each week, and since the program hing and Sterilizing Methods. An­ out some fact, the significance of which fective visual educatiOn for mdk pro­ established, nearly five thousand session was devoted to Problems of you had not preyiously taken into ac­ count. I believe all will agree that qual­ ducers must have more than general have attended. As a matter of As a sort of grand finale, "'"~L" '· 'v". ity of inspection counts much more than appeal. It must give,. step by .step, .a I presume you would like to know banq ~et was held at the completion of resume of the factors Important In sani­ the content of these sessions has course. quantity. tary milk production. Motion pict~res We have relied almost wholly upon It appears that there is a general lack are, for the most part, rather expens1ve, education. During the summer Certain points come to mind from a of organized educational programs for but certainly men in city or county can we !>hawed a film called "Our .,'""'m'" program like this. First, the in­ plant employees. Certainly this group of get together sufficient photographs to Enemy" which depicted the part had foresight enough to keep a people, entrusted with processing and make 1:1p a film strip or a series of stere­ can play in the transmission of orne of the problems that dis- pasteurizing milk, should be fully aware opticon slides in lieu of this general ~ack Later we used a March of Time milk plant operators ; therefore, a of their responsibility. I am convinced of suitable motion picture films . Smce film on cancer, then a sound film program of real value was built. that the municipal health department and milk sanitarians in an effort to improve "Body Defenses Against Disease". " AANnPr point is that the men who at­ for rural areas, the state bureau of dairy­ milk production methods should be pre­ fie in nature was a series of twelve these meetings came because of ing, should set up a rather comprehensive pared at all times to address any group opticon slides illustrating proper active interest, were in a responsive course of instruction for all persons who such as the Grange, local milk producers' dures in food handling. We are of :mind, and were able to get some are engaged in the actual processing and associations, and community clubs, a series at the present time a film strip with roblems partially if not entirely pasteurization of milk. Many are in fa­ of slides or a motion picture on milk will and entitled "For All Our Sakes" vor of licensing all persons to whom is ..... uu\..1\UUN IN ~ANITATION JOURNAL OF MILK TECHNOLOGY 167 delegated the responsibility for pasteur­ the state of 'X'? I have a son :t.flk is Safe for Babies", which from a recent questionnaire which was izing plant operation. This point must a small college there, and he tells-·m""Uilt•""'' hy :n the July, 19~6 , edition of .the sent to milk control officials throughout be borne in mind, however, that the they use raw milk. I can't quite e Digest. That IS a good article the country. The questionnaire was used 5 licensing of such persons should follow stand it. In fact, knowing some of sumer enlightenment. to determine what other departments are a fair and rather comprehensive course dangers of raw milk, I'm fnankly con . per publicity on milk is valu­ doing in the educational field. The re­ of instruction. We license people who concerned." I told him I did not ;o.Jewspa Make your articles informa- sults tabulated from replies indicated the run other mechanical equipment to pro­ too much about the milk situation i t,~r~ewsy. Do not forget that if an following: tect the safety and well-being of the state, but should write and find out n reak of milk-borne disease should o.c- 1. Fifteen out of fifty departments had no community, and it certainly is not unrea­ information received indicated th~t b. our community, you at least wtll definite planned educational program in sonable to make this requirement applica­ health department jurisdiction r.~~ Jome personal satisfaction in being milk sanita~ion. ble to milk. to pasteurized supplies but not to 1 2. Twenty-one out of the fifty had a planned to pull from your file n7wspaper program for the education of plant oper­ EDUCATION OF THE PUBLIC A·fter receiving this inquiry £nom me ·I which you wrote, at mtervals, ators. 1 es f . · Up to this point our discussion has state authorities wrote the college ' •sing the advantage o . pastebunzatwn. 3. Thirty-two of the fifty conducted a pro­ been concerned with those groups whose expressed the view that the use d in future talks or artiC~es, e sure. to gram of consumer education. good pasteurized supply was 4. Most effective* methods reported for each livelihood is derived mainly from the nt out how neglected pomts of s_amta­ of these three groups were as follows: milk business. The improvement in Then the Flint physician enlisted brought about such an outbreak. support of two other local men II practices and methods of milk handling Other means ar.e open to most of us .for Plant III is our responsibility so that the next sons were attending this cdllege and ·uroer education,. lectures, ~mlletms, Prodrtcers 0 perators The P11blic group about whom I wish to speak will quested that pasteurized milk >!)e ibits, radio\ and VISUal edu~at10n. O.ne, Demonstrations Same as for Lectures be benefitted and protected. This group Shortly after the Christmas l{ol' •ever, which do~s not permit enl~rgmg Printed Mater­ producers Radio Visual Educa- represents the consumers of milk, the gen­ letter was received from the n and which 1s r.arely ~sed, IS t.he ial Meetings and tion eral public. They are not subject to regu­ mr doctor friend, stating thl\t pa..!:teu,riJlttl otion of inspectiOn tnps to mtlk Lectures Exhibits latory control like the milk industry. Mr. milk was now being served in ants by consumer groups. Those plants News releases hall. It migh~ be said that John Q. Citizen buys his milk wherever · h have something to show encourage 5. In reply t0 the question, "Do you feel he pleases, uses as much or as little as he suggeslion, Michigan had a IJ1is· those who do not are afraid of it. that the so-called 'educational approach' cares to, and does most anything he de­ play in the milk supply., of a .. ~',"'"uv 1 'could enlighten, possibly startle, the is sometimes used as an excuse for laxity sires with it after it is placed in his sta~e. However, this does buing out lie a bit, and give some plant oper- in the enforcement of important regula­ tions and laws", twenty-five felt that it possession. Now it may be felt by some potnt that no oppol'tunity should rs more concern about their equipment II was, seven did not give an opinion, and I I that the most we can do is to assure the missed to be of setvice and to noster practices if this educational approach the remainder felt that it was not. I use of pasteurized milk. I believe consumer a good saf.e milk supply, and re · used to any great extent. It is Splendid possibilities are open to all definitely is one type of consume£ after that our respons1bility ends. I can­ ething to think about. sanitarians if some of these valuable edu­ tion. At least the college aullhorities I not subscribe to this attitude. Certainly . OUCATIONAL PROGRAMS cational approaches are used in milk con­ the light. Someti+ we q:alize our fundamental responsibility to the ELSEWHERE trol programs. consumer is to guarantee him a whole­ plishment in ra~her unprecedented (n conclusion, it would be of interest Be sure to take advantage o'f · * Personal contact was of course mentioned by some milk supply, but we do not want to point out some of the facts gathered drop him there. We want him to know like this. Many times they f.lay fine nearly all who r_eplied. why it is a good supply, what could hap­ dends. pen if it were not rigidly supervised, Here is another idea. what advantage pasteurization is from the inquiries now and again by persons standpoint of safety, and what value he ing .to know something aoout milk Automatic Pumping Equipment. S. A. Can­ and the other citizens of the community about the local supply. Make it a rch in Sewage Chemistry, Sewage Treat­ c, and Stream Pollution. Gail P. Edward~ ariis. J. Am. Water Wot·ks Assoc. 30, 1388- are getting for their money in terms of tice to ask the person's name hers. Sewage Jr?o rks f . 10, No. 2, March 1398 ( 1938). P. H. Eng. Abs. xix, W ., 25 . protection through our efforts. When dress, then in a day or two send Ill ) , pp. , 173-208. P. H. Etlg. Abs. xix. S, Equipment for automatic control of pumping the public appreciates that, then you can copy of Leslie Frank's article~ ' 2-18·39. is discussed in considerable detail. Topics con­ of health Public Should Know About Milk". is article is in itself an abstract of 123 sidered include self-priming devices, selection feel pretty sure that a good job I~ appearing in the literature of 1937. It education has been done. What are some haps they will not read the article not lend itself to further condensing and of valves for automatic operation, relief valves, methods that can be used to attain this through, but at least they will re3der is referred to the original article. water strainers, pump .motors, electric and desired objective? more sympathetic attitude, tllrough •ubject is reviewed under the headings: thermo-electric devices for motor control, pump Chemistry and Biology, (2) Activated and motor bearings, protection of equipment Possibly one or two examples will help interest, toward the health uc:IJ•uhs ago a Flint physician came into Frank's article a little too detaded, ) Mechanical Equipment. J. H. SHRADER. my office and said, "What do you know off a few mimeographed copies of about the supervision of milk supplies in tide by Guy G. Stevens, D.V.M., 168 JOURNAL OF MILK TECHNOLOGY 169

the dealers lost some of their boys, the other for girls. These camps three d in seven their business aooar- received daily about 240 quarts of sup­ ad an not affected. In one of the posedly pasteurized milk, in cans, from A Study of Milkborne Epidemics * cPtly ~~ances it was reported that gross a producer-dealer who also sold about tatter 105 on the nart of the dealer was 220 quarts daily to other customers. The Paul B. Brooks, M. D. lige?~~ for the outbreak- one of our cases in the two camps occurred, at dif­ pons1. e ferent times on the same day, about five State Department of Health, Albany, N . Y . t swous. it is a regrettable fact that there hours after consumption of milk. At the In dee d' fil h · h f time of investigation some of this milk EPIDEMIOLOGY evidence in our es. w IC orfcefs us . Considering as one g ~;oup the tn 1 remained in one can and, when the r nme outbreaks of scarlet fevet and he conclusions that 1gnorance o acts In the twenty-two year period 1917- 10 ~ch should be common knowledge phosphatase test was applied, gave a 1938 inclusive, New York State, -exclu­ sore throat occurring in the complete raw reaction. The laboratory period, responsible cases of mastitis bt n intelligent dairymen and dealers, sive of New York City, recorded 151 . g to conform to commonly recog­ reported both Staphylococcus auretts and milkborne outbreaks of sickness. New discovered in eighteen. It is almost f ~:~standards of p ractic~ in t~e milk hemolytic streptococci in samples from York City, with no raw milk other than tain that some were missed, due to the can. At the dairy ten cows were iness and to !ega 1 reqmremen ~i ~are­ a relatively small amount of certified investigators getting on the job too found to have mastitis. The usual prac­ and to reticence or actual concealment ness, or negllgence-o~e orf a a'":ef milk, recorded none. Of the diseases in­ n factors in the causatiOn o many 1 tice was to cool the raw milk in a vat volved, typhoid and paratyphoid fever the part of dairymen. In eleven oot most of our outbreaks. at the farm milkhouse and to store the contributed the largest number of out­ the eighteen, the probable human Reference has been ma?e to the after­ cans of bulk pasteurized milk in a vat breaks (75) but in two-thirds as many of infection of the cows' udders off the pasteurizing room. The investi­ outbreaks of streptococcus infection­ located. We believe, of course, that td, if any, on the bu_sbml esfs of _dehalers gation report indicated that the milk­ hose milk was responst e or e1~ teen scarlet fever and septic sore throat- th-e were human sources in the otheG tdemics. Through the cooperatiOn of house vat had been out of commission total number of victims was nearly five The conditions from which the because of a leak; and all of the cans, infected persons suffered were :t secretary of the local Chamber times as great. The other diseases were ol Commerce, we were able to get some unlabeled, were cooled in one vat, the diphtheria, poliomyelitis, bacillary dysen­ evenly divided between throat and raw milk at one end, pasteurized at the ttresting data on. the effect of ~ne of .tery, and gastroenteritis. infections, the latter most often on other. An employee at the plant agreed hands. these on business m general. This was Sixty-nine of these outbreaks occurred an epidemic of_ 511 cases of_ scarlet fever that on the day of the outbreak he may during the last twelve years of the period, ADMINISTRATIVE QU ES11IONS have gotten two cans of raw milk by ~ J. village wtth a populatiO~ of 47~2: RAISED BY EPIDEMICS and a study of the data on these has re­ about 1 in 9 of the populatiOn havmg mistake-as he apparently did. When vealed some interesting and signific:tnt Twenty-five of .tHe more impo ~tant betn ill. A ca nvass was ~ade of two 1 say the milk was cooled, I say it with facts. All excepting four occurred i~ breaks, of which a majority were of 1111nufacturing plants and sixteen other reservations: the temperature of milk in rural towns and villages. The source of let fever and seotic sore throat, pl..lces of business. The estimated ag- the vat at one visit was 70° F. Counts infection in eight was not determined but Jected as the basis of an inquir.y ptc ass from falling off of bus-iness on two bottles of pasteurized milk from the other sixty-one originated at the farm. to find the answer~·'to some IIIII the dosing of one of the manufac­ the plant were 150,000 and 360,000 This illustrates the fallacy of the still interest primarily from an otogt·aph of section oft produces cases with and without scarla­ classification into Alpha, Beta, and Gam­ udder of cow re.rpon.rible for tinal rash (apparently the only distinc­ ma streptococci is based on the reactions two milkborne outbreaks ofi scarlet '}ef•er, six months apart. tion between scarlet fever and septic produced by the organisms when incu­ sore throat) as well as cases of erysipe­ bated qn blood-agar plates. The Alpha las. When all of these conditions can group, which includes what we have be incited, as quite evidently they are, called Streptococctts viridam, produce a by the same organism, it seems equally brown discoloration and only slight or obvious that they are simply different incomplete hemolysis (dissolving of red manifestations of the same infection. Ap­ blood cells) around the colonies. Those parently, if the infection is inoculated of the Beta group produce clear, color­ into the skin of a susceptible individual, less zones of hemolysis, and so are spoken ecysipelas results. If the infection passes of as Beta-hemolytic streptococci. This through the usual oral channel, the re­ is the group that concerns us here. Those action seems to depend partly on the of the Gamma group pwduce no hemo­ toxin-producing power of the organism lysis. ln~ partly on the susceptibility of the Lancefield, on the basis of serological patient. If the original infection came tests, has subdivided the Beta-hemolytic from a case of so-called scarlet fever, it streptococci into nine sub-groups, which apprars that the susceptible recipients she has designated as A, B, C, D, E, F, B. Magnificatiotz deYt!~op scarlet fever if they have not G, H and K. This is called Lancefield's 2000 diameters ha~ tt or have been artificially immunized classification and appears to have been Jgamst it · otherwise they have what we quite generally accepted. 175 Group B probably corresponds rough­ a study as this of milkborne epidemics. ly to the old agalactae or Streptococcus Such epidemics occasion serious incon­ mastitides grouping, because it is those venience and financial loss as well as of this group which are the chief cause danger to life and health. Theoretically of bovine mastitis. However, it is Group they are preventable by strict compliance Measuring the Bacteriological Quality of Milk* A which concerns us in this discussion with health regulations and intelligent C. K. Johns becaus·e it consists almost wholly of Beta­ and conscientious application of satis­ hemolytic streptococci of human origin factory · trade practices and hygienic prin­ Science Service, Dominion Department of Agriculture. and includes the incitants of so-called ciples which should be a matter of co m­ Ottawa, Ontario, Canada. scarlet fever, septic sore throat, and ery­ mon knowledge among ordinarily V\'_el,(. sipelas, as well as serious wound infec­ informed people. Viewing the matter Of the wide variety of methods pro­ perimental error of such great magnitude tions. They are also highly infective for practically, however, not all people in posed for the bacteriological analysis of as to cause some workers to shy away the bovine udder when there are breaks the milk business are intelligent and milk, only three have come into sufficient­ from the test almost entirely. While ly general use to be adopted on this con­ in the protective tissues through which honest, any more than are all people ,j0 there ~ay ?e situations where the plate they can enter. This explains the risk any other line and not all intelligent and tinent _as official methods ( 1) . Opinions count ts still the most satisfactory test, which dairymen take when they allow honest people are well-informed concern. may dtffer concerning the. relative value ~her~ ap.l?ears_ to be a tendency to replac­ persons with sore throats and wound in­ ing hygienic principles. Generally speaR­ of these three tests (plate count, direct mg tt wtth stmpler and quicker methods fections to milk their cows. ing, therefore, the "human element" can microscopic count, and methylene blue where the latter will furnish information not be trusted. Our hope of protection reduction test) , yet properly used, each ?f equal_ value_. For example, in the grad­ SUMMARY from milkborne infection, to repeat what can help bring about a considerable im­ mg of mcommg raw milks, some cities So there are some very practical con­ is becoming an axiom and again speak. provement in trhe quality of a milk supply. have ~eplaced it with the methylene blue cl usions which can be drawn from such ing generally, lies in pasteurization. It should be unnecessary to stress at the reduct~ on test ( 4). Again, in England outset that none of the routine bacterio­ a modtfied methylene blue test has official­ logical tests tells anything concerning the ly supplanted the plate count for the rafet)l of the milk. All of them can with analysis of graded raw milks ( 15). Milkmeter-A Slide Rule for the Dairy Industries varying degrees of success, reflect 'some­ One shortcoming of the plate count is thing of the history of a given milk and B. I. Masurovsky its inability to reflect the true number of Bronx, N. Y. furnish a~ indication of its keeping qual­ ity. Whtle the milk sanitarian has gen­ organism~ P!ese?-t ~ecause of: ( 1) their uneven dtstnbutton m milk, and (2) their The determination of milk-solids-not­ where L stands for ·Quevenne lactometer erally tended to concentrate exclusively tendet?-cy to remain in clumps. Neither fat is usually calculated arithmetically by upon the former aspect, it should not be reading at 6?° F. a?-d f for percentage changmg to a more suitable agar medium subtracting the butter fat content from of butter fat m the gtven sample of milk. forgotten that the industry and the con­ (3) nor lowerjng _the incubation tempera­ the total milk solids. The latter are de­ In other words, · there is an established re· sumer are at least equally interested in ture (18) wtll unprove this situation. termined chemically, either by the gravi­ lationship of M.S.N,.f. to L. and to and the latter.. Per?aps this aspect deserves f, from shipping cans, milk­ metric or volumetric methods. In every­ this has been utilized in the construmilking time and immediately brought to the 3. The error introduced by the sweeping laboratory. Portions of each sample were of the bacteria to the surface with the then poured into contaminated utensils rising butterfat increases as reduction to simulate careless conditions of produc­ time lengthens. Therefore the test tion. Each lot was further divided into has been regarded as not reasonably two, one of which was immediately cooled accurate after the 5 y2 hour period in water to around 60° F. while the other (22, 23). was held at 90° F. for 1 hour before Although the practical significance of starting cooling. All portions were held the first objection has yet to be deter­ at 54° to 61 ° F. until the 18th hour in DIRECf MICR OSCOPIC COUNT mined, it is true that one does occasion­ order to permit a certain amount of bac­ ally encounter milks with a weakly re­ terial activity, when they were again an­ a means of diag?osing the cause ducing flora. Milks in which St1·ept. alysed. The data indicate a marked drop ·"' r quality, there. IS gen~ral agree­ agalactiae preponderate, for example, ~h t the direct m1croscop1C (Breed) in keeping quality as a result of the de­ t often show an unusually long reduction ooooo 0 00 a · d 00 ... ~ ooooa is unexcelled. An expenence ~ ~ c 0 00 lay in starting the cooling. This is also ::> w;. ~ oq_ r-:_ ~q q,o time and slow decolorization (10}. These ~ ... ~o f'-. <'I ,.... ('(') ~O NV"\1 usually determine whether reflected quite sharply in the reduction .... A.u"' ~ ca n . . .1:; N ro ,....._ H 0\ 0 fortunately are not met with very fre­ <::"' ...... ' «:«:"l"lVVQQ this method will readily detect CCiunts indicate little or no change in the ...; <> 0 ( 15) . In winter, promptly cooled milk v '0 quality milks, it involves mor~ ex­ condition of the milk. The other methods, "'... "<> c\ may contain numerous bacteria and yet 2E _g more active state . ::r:: ..Q ·-~..-. a pp l ~nt to one of the other tests . colony count to any extent. It seems diffi­ "'c:: ~ "''-4 ~ ~ ~·z g,...... - ~ .e Mention has been made of -the English cult to avoid the conclusion that the plate 1::"' C\ 00 \0 () >-v...c::- .. practice of holding samples at atmospheric count furnishes less reliable information ..._ £_g.._. ~ REDUCTASE TEST <> .. temperature before analysis. This was concerning the bacteriological condition ~~ ... The methylene blue reduction test,. like recommended by Wilson (28) on the of such milks than is furnished by other :::"' .. t:: u other methods, has its shortcommgs. .. coos · - grounds that' such a method enables a and simpler methods. ::;::., 0 0 0 0 Vi c:!.. ~ 0 0 However, the attitude of some contr~l ::: u 0 ~ 0 0 0 better differentiation to be made between ...... 0 0 0 It has been generally held that no other ...... v~c\0... \0- «)' uals in dismiss ing the test because It . ~ 8 g,...... o" varying conditions of production. Al­ method is as suitable as the plate count < ...... not always correlate well with the A . ~ u V "" though the employment of atmospheric E v ....- "' for the analysis of pasteurized milks. It e count is obviously unfair. The ex- temperature is open to criticism, there is seems not unlikely, however, that less 8 evidence leads us to suspect that in a good deal to be said for the underlying emphasis will be placed upon plate counts y instance; the plate count, rather principle of preliminary incubation. When in the future. With the development of the reduction test, is in error. The 0 0 0 0 milk is held at a temperature of 55 o F. the phosphatase test by Kay and Graham ~ c: 0 ....0 0 0 has been criticized chiefly on the fol­ ::> "" 0 0 (12.8° C.) for 18 hours, as advocated ( 11), and its subsequent modifications, "' 0 ..,.- .... o" «)' ng points : E::: u 0 by the writer (7), the saprophytic types the control official has at last a means of "' .... ince the reduction time depends on introduced by contamination have an op­ determining with precision whether or both numbers and reducing intensity portunity to grow while the udder flora not milk has been properly pasteurized. of the bacteria present, the type of remain inactive. Since it is the former After all, the safety of the milk is his organisms becomes increasingly im­ that are mainly concerned in the spoilage chief concern, and this the plate count portant in low count milks (5). of milk, a reduction test run following J ... - ---···-- .... . _ ...... -~~---~-· this preliminary incubation furnishes a TABLE 2. sure the ti!lle required by the highl Tests to M,trket Milks with High much better indication of production Resaz11rin and l'vl etbylene Bille Reduction ab le fraction of the totaL baet"t!/ of CP.ll Counts. practices and resultant keeping quality swept to the surface (r O) to red Ia Direct microscopic countl Resazurin2 Methylene blue3 than is obtained where this is omitted. dye in the body of the milk. u~ per ml. colour number reduction time hours This method has proven very useful in ticable modification of technic Cells Bacteria at 1 hour 1 61/ z detecting faulty farm practices and has maintain a more uniform 2,290,000 1,700,000" the further advantage of shortening the the organisms will yield 143,000 6 5% £~ 2,1 30,000 31,4 (17 2,060,000 8,500,000" 8 reduction time appreciably (9). nearly approaching the true 10 6% E20 1,650,000 255,000 time and must surely be rega,rded as 1 . 61,4 The importance of the errors resulting c;9 1,590,000 113,000 8 71,4 from undisturbed creaming of good milks accurate than the sta,ndard test I!) 1,510,000 42,000 1 6% is generally recognized. To avoid them, the modified technic does CEI!itelate Atl 1,460,000 1,030,000 Ell 48,000 6 7 closely with the actual bacteniat 1,360,000 5 a modified technic, in which tubes are 012 1,310,000 32,000 6 (as indicated by Breed counts 1 71,4 inverted every half-hour, has been official­ Cj 1,250,000 42,000 vidual organisms on 60 to 80 86 48,000 4 51,4 ly adopted in England (15) for the an­ 1,200,000 6 indicated by the data from 171 6~9 32,000 1 alysis of graded raw milks. With this 1,180,000 7 presented in a recent paper (IJ.J O) . .E 1,140,000 21,000 4 modification, reduction time is generally A~6 21,000 2 5Vz 1,020,000 6% shortened, variations between replicate . Ad~itte~ly, the English modified }.27 1,020,000 21,000 6 4 71,4 tubes practically disappear, and decolour­ mc, wtth tts half-hourly inversion ,\19 995,000 105.000 complicate the operation o£ the ' Al4 96,000 5 7% ization is uniform ( 6, 8, 26, 28) . Frayer 910,000 6% some places. We have found C.-19 863,000 21,000 7 (6) and Johns (8) favour the adoption A9 21,000 1 6 that inversion once every 2 h~urs 863,000 71,4 of a mixing modification on this conti­ Bl '2 765,000 42,000 3 nent, but Thornton (25, 26,. 27) disa­ results in good agreement with A2'1 grees, feeling that the high coefficient of from more frequent mixing (10) reading the tubes after 2, 4 and 6 ! ~u!~~:s ~~~~~~~~t shades between initial colour ( 0) and full pink ( 16). correlation between the two tests indicates • T b · ted at 2 hour .intervals until mctptent reductwn noted. and inverting those not reduced a u es tnver ' . little difference in their average accuracy, Loo.g chain streptocoCCI preponderant. . while the complication of the technic may of milks may be placed in fou~ limit the use of the test. with improved accuracy and shorter a si niftcantly larger proportion suggest that the r e sazu~in te~t ca~not be bation period to compensate for the 1 ~ ~~~~!t highg count milks (10). relied upon to detect mtlks wtth htgh cell Although admitting that "the variabil­ extra effort involve~. ity displayed by the standard test may .•,,f .. In our studies dthde resal zulrin colotL~rl COL:~~ther or not resazurin will replace s recor e eac 1 1our un 1 . A lead to inaccuracy in the case o'f an indi­ RESAZURIN T ESll num ber wa . . t d When methylene blue remams to be seen. t vidual sample", Thornton appears to over­ lete deco 1onzattOn was no e . . ll h' · k The resazurin test, originally mp. ired for reduction of resa- present,. pract!ca y .not mg rs nown look the fact that it is not the average for in Germany, has recently been the bme requ_ fi d concernmg the chemistry of the dye and ;. to the pmk resoru n was compare . . . . h a series of samples, but the reliability of to supplant the methylene blue .r h h bl d ction time3 its reactwns m mtlk, wh1 1e t ere are a the value obtained for each individual test (2, 16, 19). The two dtief 1\lth t e met Y1 ene ue re u ' number of features which require ex­ sample, with which we are concerned. He tages claimed for it are: ( 1) that as h!!re was excellent agreeme~t between lanation Until our knowledge of the also appears to overlook a point of funda­ information is obtainable after 1 he two tests, the pmk stag~ b~mg ~eached ~arious f·~ctors · concerned is comparable mental importance in any discussion of incubation as with 5 to 7 hours 10 bout three-qua~ters. o t le ttme re- to that in the case of methylene blue, it the relative accuracies of the two tests. methylene blue, and (2) greater uired for decolonzattOn· d · of1 ·methyle .ne seems wtse. t o d e fer fi na 1 JU. dgment . Whether regarded as an index of initial tivity to physiologically or pat:hol.ojfi11\1 lilue or resazurm. Use m t 11s manner, bacterial content or of keeping quality, abnormal milks. tbe resazurin test appears to be much SUMMARY more reliable than with the customary No one test can give us all the informa­ the test will obviously be most accurate It was expected that this ~~~·u••·~- - .. where it ·reflects the oxygen consuming sitivity to abnormal milks would e·hour reading, but loses much of its tion we desire. For the rapid detection activity of all of the bacteria growing in ously interfere with attempts to dvantage in the saving of time. of the poorest milks, the resazurin and the milk. To do this, the bacteria must the resazurin colour with the The reported sensitivity of resazurin methylene blue tests appear to have dis­ remain uniformly dispersed throughout content (direct microscopic c:ount). o abnormal milks has, in our studies, tinct advantages. They fail, however, to the milk. This would furnish what may ever, this was found not to be n much less consistent with market indicate the source of the trouble, and be called the true reduction time. Under lady significant. Instead, the milks ~han with samples from individual here the direct microscopic examination the standard technic, however, we mea- correlation was noted with ws or qua rters. The data in Table 2 is unexcelled. For the routine grading ing the minimum change •in ndicate the wide differences encountered of a series of samples, the modified 1 These grade limits correspond, otz the average, n certain amples of market milk, and methylene blue test has the advantages of to standard reduction times of 2, 5, and BY2 hours of these showing high counts2, (9). not free from criticism in this cheapness, reliabili~y , . and simplicity. 2 This lack of sensitivity of resazurin is the basis J In bQth te.•t• the tubes were inverted every 2 (Prc:;liminary tests md~cate that 1t may for the rejection of this test in Switzerland (20). the modified methylene blue test bcream routinely submitted for chemical amylnse test, have also been found w_ant­ or bacteriological examination. Results . None of these tests can definttely are available the same day that the Cross Connections in Air Conditioning. positive insurance against the passag of i ~ts when a milk sample had been samples are submitted and, if necessary, Public Wo•·ks, 69, No. 10, p. 44 (1938) . P. H. through the same. ~e all know that redly pasteurized at 143 ° F. within an hour or two after receipt of time or another valves of all types leak. Eng. Abs. xix, AC., 8. The problem seemed solved when Kay the samples. When an improperly pas­ a safe water supply is separated from a d Graham ot England published their teurized milk is found by the laboratory, "In these days of expansion of the air-con­ potable supply by valves only, the latter ditioning industry, many buildings installing contaminate the former. Assuming that hosphatase test in 1935. Our study of a city inspe~tor ·can be s-ent immediately this equipment find it desirable to provide their condition exists in some building within technic demonstrated that, while the to the distribution point involved, to own water supply for cooling purposes. Also city, should the valve separating -the two lished method was good, it was too make further examinations on the prem­ in some instances where shallow ground water water from the private supply could volved and gave results too late for an ises by means of the field test, and to take is easily available, certain industries have in­ distributing system when the static stalled their own water supply systems for in­ of the unsafe supply exceeds that in ient control of a city's milk sup­ such action as is warranted by the re­ dustrial and domestic use. It is usually the tribution system. Usually city . Mr. Scharer and other chemists in sults of his findings. In this fashion, case, however, that these same buildings are ceeds that of any private laboratory began to work on this improperly pasteuriz-ed products still on also served by the municipal water supply. conditions. It is a fact, lem and soon made significant modi­ hand can be withheld from distribution, Some place within the building the two sources are times in practically every of supply are usually connected to the same tern when a negative pressure may exist. ions and simplifications in the English and the cause of the irregularity corrected plumbing system, with that supply not in use ing these times, there will be a flow of . Two test procedures were finally before the next pasteurizing operation. being separated from the plumbing with a from the private system to the public lished: one, a laboratory test which Upon a report of positive finding involv­ gate valve, check valve, or a combination of Such conditions have resulted in ~contaminat ld be completed in about an hour, and ing country pasteurization plants, the both. This type of connection creates a of many public water supplies with the physical cross connection which should not be quent death toll from typhoid fever and other, a field test requiring about 15 country inspector is immediately notified. permitted unless the private supply meets all water-borne diseases.-South Dakota State Pme~b!d at Sixty-seventh Annual Meeting of Taking along his field test kit, he makes sanitary standards as applied to the municipal partment of Health." flcan Public Health Association in Kansas an inspection of the plant in his district, G system. Gate valves and check valves are not IJ. Mo., Oct. 28, I938. Current data added. while a city inspector is sent to intercept 182 PHOSPHATASE TEST IN NEW YORK CITY JOURNAL OF MILK TECHNOLOGY 183 that day's shipment as it enters New York to the _paste~rization room. They We now have inspectors follow During the past year, the laboratory City. The action taken relative to the the mdk bemg conveyed directly e ortt on milk or cream samples has investigated the application of these shipment will depend on the results of the heater to the cooler and bottler r ~hosphatase results which are tests to the determination of the efficiency the tests and the reports from the plant out being held for the required to the addition of 1 percent of of pasteurization of dairy by-products, inspections. minutes. There had been a ....,uavlll·.. ,i.~lk,,... or indicate ovder ~ degrfee5s dr?p ~uch as chocolate drinks, ice cream mix, As illustrative of how this procedure the previous night in the master efJl rature, or a re uct10n o mm­ cheese, and butter. The results, so far has worked, I might cite two examples. the automatic holding equipment. l · time. I should add that achieved, hold promise of a means of 1 ~olding In one case, cream samples collected from tempts made by the operator to ~£ the irregularities have been found controlling the efficiency of pasteurization a distributing establishment in the city the valve had proven unsuccessful. ..,. i:iuw•··~ of cream. of these products. A technical article and routinely submitted for chemical ex­ 1 inspectors embargoed all the bettled of the phosphatase test in pr-esenting the experimental work carried amination were found to show consider­ on the premises and stopped ~he the efficiency of pasteuriza- ?ut thus far appeared in the January 1939 able phosphatase enzyme activity. The tion. This pasteurization plant h.u been fully covered in many tssue of the Journal of Milk Technology. source of this cream was traced to a large closed for a period of three weeks. during the past year. These have At this time, our chemists feel that they cream separating and pasteurizing plant The modified phosphatase tests ._,,lllf•rarcu common defects in pasteuri­ can detect a butter or cheese made from located 300 miles from the city. Our established as a routine procedure · n detected through application of raw milk or cream and differentiate it city inspectors intercepted the nex~ ship­ Department in March 1937 after t~t. Most of these instances in New from a product made from properly pas­ ment from this plant the same mght at a great number of experimental ork Gty were not due wilfullne_ss, teurized ingredients. the railroad terminal, and tested 50 out t? minations. Both the city and country r:ather to slight shortcommgs of equtp­ In summarizing, it can be stated that of a lot of 100 cans of cream by means specters use the field test to check t or to other factors of which the the modified phosphatase test has given of the field test. These tests likewise operating efficiency of the rator was not aware, and which could to the health officials a new tool of un­ indicated a varying degree of phospha­ plants in their districts at the be detected easily by routine physical doubted value in f.urther assuring that the tase activity and the cream was not per­ regular inspections. We are now milk as furnished to consumers is safe mitted to be used for fluid purposes. In ining approximately 800 samples of ion of plants. The significance the test in milk regulation is well in- and not likely to be a carrier of disease. the meantime, a telegram was sent to the and cream weekly by the laboratory It may some day be found that the devel­ ted by its widespread adoption by country milk inspector to visit the pas­ od alone. Altogether more than opment of the phosphatase test has been ch officials throughout the country, teurizing plant at once. After consider­ determinations have been made by the most important contribution to sani­ able checking of all equipment and steps staff. This figure includes tests on hm a comparatively short period of tary milk control since the inception of in the operation, certain irregularities milk and cream sameles done in the pasteuTization. were found, including leaking outlet oratory and a larg~· ·number of fi eld valves. The plant representatives were We have acquainted the industry shown the phosphatase test and adopted the technic and application of the it at once as a .routine check on their op­ through lectures and erations. Shipments of cream were dis­ Operators of paste ~ing plants have _,.,..... -.,. ll'umblers of Milk for Restaurant ling. A practice is made of removing the hood continued for several days until all irregu­ voluntarily adoptedr these tests for The Milk De,t/e,.. April 1938. The at . th~ restauran.t table before the customer. By larities were corrected. Thereafter, no control of pasteurization ; they have 1, No.2, July p. 21 (1938). P. H. dnnkmg the m1lk d1rectly from the tumbler it further improper pasteurization was noted the routine use of the field test most Abs. 19, Mi, 6, 3-4·39. avoids the use. of an additional glass which is and all phosphatase tests have been satis­ usually heated to room temperature and often able for this purpose. · e Harding Hotel Co., Chicago, Ill. real­ dusty. This method also assures the customer factory from this source. that milk need not be handled more than of the proper proportion of cream in his glass Another instance involving a city pas­ RESULTS OF USE OF TL"~'r ltl! drink from." amination. The information of the posi­ tion. Within a few months, tive reaction was forwarded to the milk indicating such irregularities were division in the afternoon, and that same ly reduced; during the past year evening inspectors were sent to the pas­ tically no gross irregularities have teurization plant to make further checks discovered. During the firs t;< three and note operations. The field phospha­ after the tests were routinely tase test showed milk stored in the ice­ percent of the samples sho~ed. box and representing milk that had just deviations from prope~ pas teur_,~tiOn been processed that night as being prac­ present, such minor trregularut1es tically raw. Inspectors then proceeded in about 2 percent of the samples 184 JOURNAL OF MiLK TECHNOLOGY 185

laboratory in which a particular test was at about 160° F. Do not shake bottles developed probably would agree better be.tween ~eriods of centrifuging as thM; with those by the Roese-Gottlieb method wtll drastically lower the fat reading. 9. Place bottles in water bath at 13 5 to 140 ° Report of Committee on Laboratory Methods than similar comparisons between meth­ F. for five minutes. Carefully add two or ods not developed or commonly used in three drops of glymol* and read usino A. H. Robertson, Chai1·ma1t that laboratory. The results of the 1938 dividers. Measure from bottom of lowe~ meniscus to line between glymol and fat. State Office Building, Albany, N. Y. comparisons no doubt have been influ­ enced by such facts. 2 . FUCOMA OR GERBER METHOD FOR DETERMINING FAT CONTENT OF ICE CREAM The official method for determining has deemed it unwise to adopt officially The number of methods are limited be­ any of them for determining the .fat con. cause whatever ones are given tentative Apparatus: the fat content in frozen desserts is the 1. 15 .percent or 2 5 percent, 5 gram ice time-honored Roese-Gottlieb procedure. tent of ice cream. In spite of this action, recognition herewith to be used as sort­ cream test bottles (Gerber style). Some public health laboratories are not there does seem to be a real need for a ing tests only, will be used indiscriminate­ 2. Special adjustable stoppers for Gerber too familiar with this official procedure rapid sorting test whereby all samples ly in some laboratories. Because of the bottles and adjusting key . could be examined and those which ap­ general lack of expertness and the need 3. Gerber centrifuge or 9 inch Babcock and others do not have the Mojonnier fat centrifuge. A short piece of rubber hose, testing equipment which is essentially the proach, or are below, the statutory stand­ for selection of a procedure least apt to large enough to fit around the test bottle mechanically-improved, assembled Roese­ ard might be selected for further examina. cause confusion, only three are listed as and into the bottle holders, in a Babcock Gottlieb apparatus. Because the official tion by the official Roese-Gottlieb method. follows: machine 'erves as a satisfactory adapter Among the frozen dessert products are for the latter type of machine. fat extractiOn method is somewhat time­ 1. Pennsylvania or Doan. 4. Torsion balance. consuming, especially where the analysis the regular ice creams, sherbets, ices, cus. 2. Fucoma or Gerber. 5. 10 cc. pipette for acid. is required on large numbers of samples, tards and the miscellaneous group of 3. Illindis or Garrett-Overman. 6. 5 cc. pipette for water. numerous modifications of the Babcock frozen confections, specialties, novelties 7. 1 cc. pipette for amyl alcohol. method have been introduced for esti· etc. Attention has been focused on th~ 1. PENNSYLVANIA OR DOAN METHOD Reage11ts: FOR DETERMINING FAT CONTENT OF ICE CREAM mating the fat content of frozen desserts. ice cream products ·and these have be!!n 1. For ice cream other than chocolate Apparatus: Ravored- Obviously the Babcock procedure is a subdivided arbitrarily into three groups: - the extract fla'vored, the fruit, nut or 1. Standard ice cream test bottles, 6 inch, 9 Regular sulfuric acid s.g. 1.82 to 1.83 at rapid technic originally designed only for gram, 20 percent, with graduation marks 68° F.-87 parts, and water-13 parts. milk and cream, and even as such, a slight seed flavored, and the chocolate flavored at each 0.2 percent. 2. For ch<;>co late Ravored ice cream only­ degree of accuracy has been sacr-ificed for ice creams, because of different conditions 2. Babcock centrifuge. Regular sulfuric acid !.g. 1.82 to 1.83 at 68° F.-94 parts and water-6 parts. this adaptation. When workers attempt encountered in the anlY.sis of each. 3. Torsion balance. 4. 9 cc. pipette. (Always add acid to water, never add to apply the original technic or one of its The 1936 survey- · by the Committee water to acid). various modifications to frozen desserts, showed that the following rapid metho ds Ret~gelltJ: 3. Amyl alcohol, special for milk fat de­ were used most common! y: ( 1) glacial 1. Ammonium hydroxide c.p., 28 to 29 per· termination ~ needless to say, confusion exists because cent. Procedure: the accuracy is invariably further de­ acetic acid-sulfuric acid Babcock modi fi. 2. Normal butyl alcohol, c.p. 1. Mark bottles plainly. creased according to the skill of the cation, ( 2) Lichten,t>.urg, ( 3) Illinois or 3. Diluted sulfuric acid, s.g. 1.73. Garrett-Overman, ( 4) Minnesota, (5 ) 2. Measure 10 cc. of acid of the proper operator. Procedu,.e: .strength into two ice cream bottles. The presence of cane sugar and choco­ Nebraska or Crowe, (6) Fucoma or @er. 1. Mark bottles plainly. 3. Balance the bottles on a sensitive Torsion late (or cocoa) and the fact that the mix ber, and (7) Pennsylvania or IJ>oan 2. Balance two bottles on a sensitive Torsion balan,ce. is homogenized are direct causes of irreg­ method. balance. 4. Bring ice cream in the closed jar to a The original plan this year was to com· 3. Bring ice cream in the closed jar to a temperature slightly below 80° F., ularities in the results when the usual temperature slightly below 80° F., thoroughly redistribute the fat but do not modifications of the Babcock procedure pare each of the several methods with the thoroughly redistribute the fat, preferably churn it. Mix thoroughly with spatula are used. As a result, non-acid, fat-lib­ Roese-Gottlieb procedure in order to de­ by rotating the bottle, but do not churn it. removing all tenaceous materials from the erating agents have been suggested as termine which could' be recommended :Mix thoroughly with spatula, removing sides of the container and breaking up all with the least reservations. Only a few all tenacious materials from the sides of lumps. substitutes for the original acid digestion the container and breaking up all lumps. 5. Carefully weigh 5 grams of the ice cream procedure. Some workers, preliminary members of the 1938 Committee welt 4. Immediately weigh 9 grams of the mix­ mixture into the previously balanced test to the aoid digestion, have made a partial able to aid in the comparisons, and con· ture into the previously balanced milk bottle. ether extraction of the fat in the Bab­ sequently the data from which to dra\\ test bottle. 6. Add 5 cc. of water and 1 cc. of amyl conclusions are not as complete as might 5. Add 2 cc. of ammonium hydroxide and alcohol. cock bottle, but with only limited success. mix thoroughly. 7. Insert stopper and shake until all curd The variety of simplified tests is such that be desired. Your chairman has examined 6. Add 3 cc. of normal butyl alcohol and is dissolved. it is apt to confuse the laboratory worker other sets of comparative analyses which mix thoroughly. because so little is said about their limita· show definite!}' that fairly good agr 7. Add 17 .5 cc. of sulfuric acid and mix * Glymol is a mixture of mineral oil con­ tions. Because of the irregularities re­ ment can be obtained with many of t thoroughly. taining a small percentage of a red or blue rapid technics, providing the work

8. Thea mix acid remaining in neck of bottle 7. Place test bottle in a shallow water bath, ROESE-GOTTLEIB METHOD, OFFICIAl. FOR time with 15 cc. of each ether; shake vigorously by inverting test bottle several times. heat to boiling, and continue heating for DETERMINING THE FAT CONTENT OF ICE CREAM 30 seconds after each addition; and allow to 9. Centrifuge for 6 minutes at regulation several minutes. Shake two or three times settle. Draw off the dear soln through the speed for your centrifuge at approximately during heating interval. Usually the fat /J.p parattiJ: small filter into the same flask as before and 160° F. (heated machine). will spread on the surface in a clear 1. Analytical balance. wash the tip of the spigot, the funnel, and the 10. Place bottles in a water bath at 135 to yellow liquid in from 15 to 30 minutes. 2. Beaker, 100 cc. filter with a few cc. of a mixture of the two 140° F. for 5 minutes before reading the Heat until the fat has definitely separated 3. Steam water bath. ethers, in equal parts, free from suspendec fat column. from the dark portion of the liquid and 4. Drying oven operated at 100° C. H,O. To insure complete removal of the fat, 11. Read percentage of fat promptly by ad­ has become perfectly clear. 5. Mojonnier extraction flasks . a third extraction is necessary. This third ex­ justing the height of the fat column to 8. Centr_ifuge at regulation speed for your 6. Mojonnier fat drying dishes. traction yields less than 1 mg. of fat if the zero or some other whole percentage grad­ machme for 5, 2 and 1 minutes adding 7. Funnels, 3 inch diameter. previous ether-fat solos have been drawn off uation. Use stopper key for this adjust­ ·water at 180 to 200° F. as in the regular 8. Desiccator. closely. Add a glass bead and evaporate the ment. Babcock procedure, using a macbine Materials: ethers slowly on a steam bath; then dry the Note: The Gerber test bottles can not be used at approximately 160° F. Do not soften fat in a boiling water oven to constant weight. the water with acid. 1. Ethyl ether. Weigh the flask with a similar flask as a in a standard Babcock centrifuge for 6 2. Petroleum ether. inch bottles. Difficulty has occasion­ 9. Place bottles in water bath at 135 to 140° counterpoise. Do not wipe the flask immedi­ 3. Filter paper.! ately before weighing. ally been experienced in getting uni­ F. f~r 5 minutes. Do not add glymol. 4. Ammonium hydroxide, c.p., 28-29%. form test bottles from the manufacturer Readmgs are more nearly correct if the fat Remove the fat completely with petroleum through their representative, Dairy In­ column is measured from the bottom to Procedut"e: ether. Deduct the weight of the dried flask dustries Supply Co., 216-218 Water the extreme top of the fat column as in Weigh 4 g. of the thoroughly mixed sample with residue and bead to obtain weight of fat. Street, New York City. the regular Babcock test when applied to into a small dry beaker·; add 3 cc. of H,O; Finally, correct this weight by a blank de­ whole milk.* thoroughly mix with a glass rod; and transfer termination on the reagents used. to a Riihrig tube or a similar apparatus (use 3. ILLINOIS OR GARRETT-OVERMAN METHOD There are some objections to the use Mojonnier fat ,extraction flask), washing out A. H . ROBERTSON, Chairman. FOR DETERMINING FAT CONTENT OF ICE CREAM of a tempering bath at 135 to 140° F., the remaining portion with the aid of an addi­ GEORGE E. BoLLING, Brockton, Mass. ApparatuJ: tional 3cc. of H,O. Add 2 cc. of NJ-I,OH, mix H. E. BoWMAN, North Acton, Mass. because occasionally seeds and other bits thoroughly, and heat in a water bath at 60°. ]AMES P. BuCKLEY, Philadelphia, Pa. 1. Standard ice cream test bottles, 6 inch, 9 of non-fatty materials attach themselves Add 10 cc. of 95% alcohol and mix well. Add R. L. GRIFFITH, Oakland, Cal. gram, 20 percent, with graduation marks 25 cc. of ether, shake vigorously for 30 seconds, D. W . HoRN, Bryn Mawr, Pa. at each 0.2 percent. so firmly to the glass in the neck of tlie add 25 cc. of petroleum ether (redistilled C. K. JoHNS, Ottawa, Canada 2. Babcock centrifuge. test bottle that they are not drawn down.• slowly at a temperature below 65 °), and shake H. W . LEAHY, Rochester, N . Y. 3. Torsion balance. ward beneath the fat column as the latter again for 30 seconds. Let stand 20 minutes, F. L. MICKLE, Hartford, Conn. 4. 9 cc. pipette. or until the upper liquid is practically clear. HORATIO 'N. PARKER, Jacksonville, Fla. 5. Shallow pan, 2Y2" deep, which can be is cooled to the proper temperature for Draw off into a flask (use Mojonnier fat dry­ M. E. PARKER, Chicago, III. heated to 212° F. reading. This occurs in both the Gerbe.l' ing dishes) through a small, quick-acting filter ]. H. SHRADER, East Orange, N. ]. 6. Burette measuring in 0.5 cc. graduations and Babcock test bottles·.'· In spite of this as much as possible of the ether-fat soln H. R. THORNTON, Edmonton, Alberta or a 2. 5 cc. transfer pipette. (usuJily 0.5-0.8 cc. will be left.) Again ex­ H. 0. WAY, Cleveland, Ohio ReagelltJ: objection, the use of tempering baths is tract the liquid remaining in the tube, this F. P. WILCOX, Los Angeles, Cal. A. Mixture of 75 cc. of ammonium hydrox­ recommended where a large number of ide c.p., (28-29%); 35 cc. of normal tests are to be read immediately a£ter butyl alcohol; and 15 cc. of 95% ethyl centrifuging. Reading'§'based on fat col­ alcohol. Keep in tightly stoppered bottle. New Connecticut Sediment Standards Health Laboratories approved for the Ex­ B. Mixture of 200 grams of trisodium phos­ umns containing bits of foreign matenials A new 1939 edition of the Connecti­ amination of Milk should arrange to use phate and 150 grams of sodium acetate are :unreliable. cut Official Milk Sediment Standard has the 1939 edition as soon as possible and dissolved in 1000 cc. of distilled water. been approved jointly by the State Dairy should have it in use not later than De­ Keep in tightly stoppered bottle. The above sorting methods are to be and Food Commissioner and the State cember 31, 1939. The 1931 edition Procedwre: used for picking out frozen dessert prod­ ucts suspected of having a fat content be­ Commissioner of Health for laboratory, should not be used after that date. 1. Mark bottles plainly. plant and field use in Connecticut. This 2. Balance two bottles on the Torsion low standard. Samples thus suspected are Copies of the 1939 standard will be balance. to be examined further by'the Roese-Gott· new standard is a considerable improve­ available for distribution probably with­ 3. Bring ice cream in the closed jar to a lieb method. An adaptation of the lat­ ment over the old. in the next two or three weeks, at fifty temperature slightly below 80° F., ter, using in part the Mojonnier extcac· The seldom used "Excessively Dirty" cents a copy. This price covers the cost thoroughly redistribute the fat, preferably discs, h

overrun. At 80% overrun, the ice cream isted between the sources of serum solids seemed slightly moist, while it was no­ and the development of the ice lumps t" ceably moist at 70% overrun, and very (which is presumably rel"ated to the ex­ definitely moist at 60% overrun. Small tent of protein hydration) a batch of A Note on Ice Lump Formation in Ice Cream (pinpoint) ice lumps were noticeable at mix was prepared which was identical in Frozen in Continuous Freezers 60% overrun. At 50% overrun, small composition to the basic mix, but which ice lumps (approximately 1/ 32 of an employed skim powder to complete its David Levowitz, Ph.D., inch in diameter) were readily observed. serum solids. This mix developed moist sheen and ice 1umps at the mouth, and Director, New Jersey Dairy Laboratories, New Brunswick, N. J. A by-pass valve attached to the mouth of the continuous freezer allowed the di­ after passage through the fruit injector at the same overruns which were ob­ Ice cream frozen in continuous freezers Ser-ious ice lump formation was en­ version of ice cream at the various over­ served with the basic mix. A novelty has sometimes been found to contain countered in the ice cream manufactured runs through the pipe lines and fruit in­ mix prepared with sk;im powder also small lumps of ice. Ramsey, of the Tell­ jector assembly. It was found that pin­ at a New Jersey plant recently, after a behaved in the same manner as did the ing Belle Vernon Company, Cleveland, point ice particles were present in the new fruit injector was installed. This original novelty mix. presented a paper entitled, "The Cause plant, equipped with newly reconditioned ice cream drawn from the .fruit feeder at The substitution of vegetable gum for and Remedy for the Separation of Milk continuous ,freezers, had been operating 90% overrun; the particles were approxi­ gelatin in both basic and novelty mixes Solids in Ice Cream Frozen in Continuous satisfactorily prior to the advent of the mately 1/ 32 of an inch ·in diameter at did not change the overruns at which Freezers," at the recent International As­ fruit device. The equipment manufac­ SO% overrun ; at 70% overrun the par­ moist sheen and ice lump formation were sociation of lee Cream M'anufacturers con­ turer's representatives informed the plant tides were 1/ ~ 6 of an inch in diameter; while at 60%rthey were more than of noticed. Increasing the amount of sta­ vention. This was the first time at which management that t~1~ defect was ~robably Ys bilizer and omitting it completely also this ice lump formation has been recog­ due to the compos"Jt!On of the mtx, since an inch in diameter--the product at this seemed without particular effect. nized as a definite problem. all other factors were satisfactory, and a. po int looked like oat-meal. At 50% overrun, the product could hardly be A batch of high fat mix (18% fat, . ~amsey descr!bed the de.fect as arising New York plant, employing identical called ice cream ; it resembled puffed-rice, 42.9% total solids) used for a special m ICe cream whiCh left the freezers with a equipment, expe~ienced no difficulties. "wet" sheen ; such ice creams contained if the cereal analogy is permissable. account was put through a freezing trial. small ice lumps (approximately 1/32 of RELATION OF ICE TO OVERRUN The regular "basic" mix contained 12% This mix was .found to get to the oat-meal stage at 50% overrun as against 60% for an inch in diameter) at the mouth of the Mix prepared at the local plant was fa t and 39.4% total solids. The fat was the basic mix. This high fat mix was f.reezer. Alter passage through a pipe brought to the New, ,York factory. In contributed in equal portions by fresh made from the same ingredients used in line .and fruit injector, larger lumps (ap­ was found that the ·mix yielded a sound 6uid cream and by frozen cream. The the preparation of the basic. proxim~~ely Ys of an inch in diameter) "dry surfaced" product, when the freez­ serum solids were completed by con­ were VISible. The lumps were dispersed ers were maintained at the same adjust­ densed skim milk. Non-dairy solids Our findings indicated that the points uniformly through the product. When ments used by the New York company. were supplied by sugar syrup, desiccated at which lump formation appeared in the the ice cream came from the freezer The overruns for whit;h the freezers were egg yolk, and gelatin. novelty, basic, and high fat mixes were "moist", overruns were difficult to con­ adjusted were between 110 and 120%. The "novelty" mix prepared at this related,, possibly, to the concentration of trol. The hardened ice cream did not The New Jersey plant supplied its trade plant, testing 10% fat and 37.3% total either fat, or serum solids, or total solids sh

It was found that increasing the total the friction of the ·freezer barrel, or pipe solids contents of the specific mix in any lines, the thick, fluid cell walls will be manner delayed the appearance of the deformed, and the water held in the walls "moist" surface of the ice cream at the may be made available to the ice crystals A Method for Checking the Holding Time in Short mouth of the freezer, and of the "oat­ already formed, so that their size in­ meal" consistency at the mouth of the creases, or the ice crystals from one sec­ Time High Temperature Pasteurizers fruit injector. tion of the cell may be brought into prox­ imity with those of another section, to D. M. Roger HYPOTHESIS FOR ICE FORMATION cause the formation of larger ice aggre­ Laboratory D ept., The Borden Farm Products Co., Brooklyn, N. Y. When an ice cream leaves the mouth of gates. the continuous freezer with a "dry" sur­ The hypothesis indicates that the defect> The usual method of checking the point the salt solution passes a pair of face, it passes through pipe lines . as. a could be eliminated by the reduction of holding time of a short time-high tem­ electrodes connected to a circuit joining plug, and will pass through a frutt m­ the size of the air cells in the ice cream. perature pasteurizer is to pasteurize water, dry cells and a microammeter. Another jector with little or no alteration. The A greater number of air cells per unif inject dye at the entrance of the holding pair of electrodes connected to a similar "moist" surfaced product will offer fric­ weight would result in thinner foam chamber, and measure th~ elapse of time circuit is placed at the outlet of the hold­ tion to the walls of the pipes and the sur­ walls, which would conta·in less free water before the dye can be detected at the out­ ing chamber. The salt solution passing faces of the fruit injector, and will be at the time of emerging from the freezet Jet of the holding. chamber. Anyone these electrodes will increase the con­ "rolled" rather than be "pushed" through. and therefore resist torque to a greater who has worked with this method is ductivity, and allow more current to pass The surface condition of the ice cream degree. Modification of the continuous fully aware of the attending complica- through the circuit, causing a sharp de­ leaving the freezer is indicative of the freezer motor drives would be necessary cations. ., flection of the ammeter. The arrange­ proportional amount of moistur~ in the to decrease the size of the air cells, since The following procedure seems to have ment of the apparatus is illustrated in air cell walls. On the assumptwn that the present models are generally equipped some advantages over the dye method. Figure 1. continuous freezers yield air cells of con­ with constant speed dashers, which do A saturated sodium chloride solution The operation is simple: One person stant size, the thickness of the cell walls not allow the sizes ·of the air cells to vary. is injected into the stream of water en­ injects the salt solution. Another op­ depends on the ice cream's overrun; high The trials reported above were under­ tering the holding chamber. At this erator starts the stop watch when the overruns mean thin cell walls, while low taken to obtain a practical solution to a percentages mean thicker cell walls. The troublesome plant condibion. The method thicker cell walls will contain a larger detailed eliminated the difficulty ·fo~ the proportion of availa:ble moisture, since plant concerned. It. .. is hoped that this more or less constant percentages of water method may aid other· plant men, at least are converted into ice in the freezing pro­ until such time that carefully controllad cess. A hypothesis is offered: these research work on the problem of ice 1\:unp A • RU~~Eil 5TOI'!'ER. thicker more fluid cell walls will present formation leads to a mor.e perfect under· b • .5TJJIOAilP *'."RASS Tl"E 0 • COI'PER WIRE 12 6AI/6'.E 8#5 less resistance to torque than the thinner, standing of the med'ranism involved, and Oz.. 2S M l l.liAHI'EIU .U~T~IZ , Gx· 5 Mll l./AMI'~R£ i.IET~~ drier cell walls. Under the influence of to better methods. P · /. S VOJ.r OilY C~Li.

HOLDI NG CHAMbl!l(

ENLARGED YI£W 0' ELlfCTI?0«5

5ATURATI!O I IT 1:1 IU'TT~R I~ TN~ IMI~CTIN

SO-JOO,.~ . MET"A.L SYRING~

Drawing by courtesy of Mr. N . A. \Xfalby FIGURE 1 Equipment aJSembly for determillillg holdiug time for high-short pasteurizers. 192 MEASURING oF HoLDING TIME 19'3 galvanometer at the entrance shows a A 25 milliampere meter subdivided in­ deflection, and stops it when the gal­ to milliamperes was used at the inlet of vanometer at the outlet shows a deflec­ the holding chamber; at the outlet of tion. When dye was added to the salt the holding chamber, a 5 milliampere Report of Committee on Ice Cream Sanitation* solution it was found that this method meter subdivided into 0.1 milliampere. would predict the exact moment when These milliammeters need not be ac­ F. W. Fabian, Chairmatt the first dye might be detected at the curate but they should be sensitive. Michigan State College, East Lansing, Mich. outlet. It is much easier to watch for Meters of this type can usually be pur­ and time the deflection of a galvanometer chased cheaply at any store dealing in The Committee wishes to bring to the did not have sufficient milk fat to qualify than it is to catch and time the first us·ed radio oarts. attention of the Association several de­ as ice cream but more than enough to appearance of dye. An electrode is made by passing two velopments in the frozen desserts field classify it as a sherbet which, as a rule, 12 gauge ~ & S copper wires through :1 It does not require much ability as an that have taken place during the year. has approximately 2 percent milk fat. electrician to prepare this equipment. It rubber stopper, and fastening the stopper Throughout the whole country a greater The fact that malted milk was frozen was found that the polarization of the in a %" brass T . By adjusting the area of interest is being taken in frozen desserts, changed the whole picture from a legal electrodes did not interfere, but care was the electrode to be exposed to the salt as evidenced by the enactment of laws standpoint. There has been no objec­ taken not to close the switch until just solution, a suitable deflection on the milli­ by many states and cities and the draft­ tion to se!Jing malted milks in a liquid before the test. ammeter can be obtained. ing of a Frozen Desserts Ordinance by state no matter what their milk fat con­ the U. S. Public Health Service. tent might be but when heat was re­ The foundation for the whole industry moved the status of the whole problem has been bui1't around one product- ice changed. Here is an example of where cream. While ice cream still leads all the physical rather than the chemical Cross-Connections in Plumbing Systems other forms of frozen dess·erts in pro­ composition determined the legality of Information on which to base effective formance characteristics of a siphon­ duction and doubtless will for many the product. health regulations pertaining to the in­ breaker are determined. The effective. years to come, there is evidence to indi­ The reason is clear to those familiar stallation of plumbing is supplied in this ness of various types of siphon-breakers cate that other forms of frozen desserts with the situation since it is evident that publication. It deals principally with in preventing backflow is discussed, and are gaining in popularity, and that more with the frosted malted milk, or any the operation of one type of flush valve cognizance should be taken of them. other simiiar frozen dessert, it is an at­ the technical aspects of the problem of is explained in order t? .show the esse!l­ The American Public Health Associa­ tempt to imitate ice cream. With any preventing the backflow of water from tials of a table flush Valve, that is, one tion has just recently appointed a joint frozen milk of whatever flavor, it would plumbing fixtures into water supply sys­ which will not open under any possible Committee on Frozen Desserts consisting be hard for the public to distinguish be­ tems. reduction in supply pressure. Finally,', of members from the Laboratory Section tween a frozen milk containing 6 or 7 It starts with a general review of the there is given a brief review of the entire and from the Food and Nutrition Sec­ percent of milk fat by weight, and choc­ subject, including a brief history of pre­ subject of preventio,g backflow from tion. This committee is now busy pre­ olate or fruit ice cream containing 8 vious work on the subject, a classifica­ plumbing fixtures, in which two distinct paring standard methods for the analysis percent• by weight of milk fat as re­ tion of cross-connections, and a brief methods of attack are pointed out, and of frozen desserts, to be eventually pub­ quired in many state laws. discussion of vacua and siphon action. the merits of each are discussed. The lished doubtlessly in conjunction with This is followed by a mathematical and conclusions relate only to the technical the Standard Methods of Milk Analysis. IMITATION ICE CREAM experimental an·alysis of the conditions aspects of the subject and do not take the In view of the broadening scope of this Furthermore, many states provide for tending to produce backflow into a sup­ form of proposed health or plumbing field , your Committee suggests that proper just such products by requiring that they ply line. This analysis makes it possible regulations. steps be taken to change the name from be labelled imitation ice cream. Some to determine the worst conditions, as re­ It is well illustrated with sketches of the Committee on Ice Cream Sanitation states even require that a license be se­ gards backflow, that can occur in any supply systems, cross connections, general to that of the Committee on Frozen Des­ cured before such products can be manu­ building supply system, and to determine layout, siphon-breakers, flush valves, and serts Sanitation. factured. So far, there has been little minimum requirements for the positive testing apparatus, and contains a biblio· excuse for the manufacture of products prevention of 'backflow under these con­ graphy of 29 references-Roy B. Hunter, FROSTED MAL TED MILK covering the range between sherbets con· ditions. Specifically, the minimum pres­ Gene E. Golden, and Herbert N. Eaton, The appearance of a new frozen des­ taining from 2 to 3 percent milk fat and sure that can occur in any system, the Journal of Research of the National sert on the market known as frosted ice cream containing 8 to 10 percent milk maximum rate at which water can be Bureau of Standards, Vol. 20, April, PP· malted milk brought out some rather in­ fat. Some might think that it would be removed from the supply risers under 479-542, 1938. This report can be pur· teresting things relative to our frozen a fine way to utilize more milk. How­ this minimum pressure, the smallest air chased as Research Paper RP 1086, desserts laws. Here was a product that ever, they lose sight of the fact that this gap between a faucet and plumbing fix­ Superintendent of Documents, Wa5hing· type of frozen dessert sells for the same I ture that can be safely allowed under the • Presented at the Twenty-seventh Annual Meeting price as ice cream so no greater sales ton, D. C., price 15c. oCfl International Association of Milk Sanitarians, worst conditions, and the essential per- J. H. SH!v\Dllll. cveland, Ohio, Oct. 19·21, 1938. volume may be expected, an~ those who It 1Cc ~REAM ~ANITATION JOURNAL OF MILK TECHNOLOGY 195 ~. -~..___, ~~--\ r.. ••l ;;,. , .... eat this type of frozen dessert actually gallon, the last named method seems to BACTERIAL STANDARDS we pasteurize ;:r,'~J~, :a'n'i!. lCe · crea m ~m( ?'··. get less milk fat and solids and therefore have been adopted by the greatest num­ Twelve states at present have state­ in the sa~ ~ ~~-~ u,rizer, : oole~, over the '~ :. ber of states. It is likewise the method ol/iT~ , r· • •" " , less nutritional value. ments of the maximum bacterial content same coCARTONS 10. Utah ...... 100,000 per cc. plain sale. Our experience with these nov­ 500,000 per cc. fruit & nut season is a door connected with the cold elties is that they are flashes in the pan A new development in the milk in­ 11. Wisconsin .... 100,00Q per gram room. Therefore, should we require that that go for a little while and then the dustry has been the sanitary regulation 12. Kansas ...... 100,000 per gram the entrance to the milk room and the public forgets." ·Of the manufacture and sanitary control ice cream room should be through a cold AGENCIES CONTROLLING MILK HYGIENE of paper containers and cartons used · room if fly protection is not given in an· WEIGHT VERSUS VOLUME Public 'health laws and regulations de­ the dispensing of milk. Paper cartoll.S other manner?" For years ice cream was sold on a and containers are used more ·extensively rive their validity from police force, which constitutionally resides in the state Dr. Andrew J. Krog has the following volume basis only. As the industry in­ for storing and dispensing frozen des­ comments and suggestions to make: creased in size and competition became serts than for milk. Furthermore, the governments. The administration of the laws may be vested in various state agen­ "A. Homogenizers: The present type of keener, .the amount of air incorporated same precautions, as a rule, have to be asbestos rubber packed pistons used in into the mix during freezing by some taken in their manufacture and storage cies. A survey by the special Committee of the American Veterinary Medical As­ homogenizing should be replaced by manufacturers reached fraudulent pro­ as are being ad~ocated for milk. a device of a more sanitary nature. portions. It soon became evident to con­ sociation on Food Hygiene in 1937 There is no reason to beli·eve that •the showed that in the 48 states the milk Homqgenizers designed to be taken trol officials and to the manufacturers same sanitary requirements should not l)e down rapidly, and capable of complete who had the best interests of the indus­ hygiene control is distributed among the enforced in the manufacture and subse­ following agencies: sterilization without the destruction of try at heart that something should be quent handling of p.aper containers an4 packings, should be adopted as stand­ done to control the amount of air per­ Number of states in which milk sani- cartons for frozen desserts as for milk tation is done by: ard equipment. There is such equip· mitted in the finished product. Your Committee, therefore, recommends ment on the market at the present time. Different states have attempted to cor­ State Health Department...... 22 that this Association in the future snail State Agricultural Department.... 12 B. Food Colors: Aqueous solutions of rect the abuse in various ways . Some consider only those paper containers and State Health Dept. and other certified colors ·for ice cream are gen­ states, such as Wisconsin, specify the cartons satisfactory .rfor storing and re­ Agency ············-········-···········- IO erally made up from powder bases at Some other dept...... 4 amount of overrun permitted. Other tailing frozen desserts when they lia.ve , ice cream plants and are in most in­ states, such as Alabama, California, Con­ satisfied all the principles of sanitation to Total...... 48 stances stored for a comparatively long necticut, Florida, Idaho, Massachusetts, be observed in their manufacture and use period of time at room temperature. Michigan, New York, South Dakota, and as are stipulated in the Journal of Nfilk OTHER SANITARY CONSIDERATIONS Their composition, time of storage, Utah, stipulate the minimum weight per Technology, Volume I, No. 5, pp. 50·53, Mr. Ralph E. Ir·win states that: and room temperature enable them to gallon in terms of food solids per gal­ Items 1 to 11 inclusive, that are being "Th<:: following three questions are under become excellent culture media for lon ( 1.6 lbs. food solids per gallon.) advocated for paper containers to be consideration here in Pennsylvania: organ isms which may be introduced Another variation of the same idea is used for milk. 1. From a public health standpoint should through contamination. Methods for defining both the weight and food solids we permit the preparation of milk and the stabilization of these color solu- BACTERIAL STANDARDS per gallon as in South Carolina (weight ice cream in the same room in the milk tions should be adopted, and use of a -4.5 lbs. and food solids per gallon- Each year a few more states are a da~d and ice cream plant ? In doing this, we chemical preservative may be consid· 1.6lbs.) and Pennsylvania (weight-4.75 to the list of those having a bacter1al will have equipment for pasteurizing, ered. I think this is a decided factor lbs. and food solids per gallon-1.8 lbs.) standard for ice cream. In 1927 Calif· cooling, bottling and separating and in the bacterial content of ice cream. or just the weight per ga

Milk from a regenerator was clarified at A crucial test was made on the cream the market which uses a cabinet heater the requirements of indicating thermo­ a temperature of 137° F. (for 10 sec­ volume from high-short pasteurization as and cooler with milk to water to milk meters located on pasteurization pipe onds) with the following average results: compared with low-long holding, in both regeneration and an open gravity holder. lines. Bacteria counts cases using milk from the same vat, and The U. S. Public Health Service has The holding time is dependent upon Before After filtering. promulgated requirements for the con­ the size of the holder pipe, the pressure clarification clarification Cream volume struction and operation of high-short pas­ and vacuum, and the speed of the pump. Average of 19 High-short Low-long teurizers summarized as follows: Immediately after installation or any re­ samples --· ----- 183,000 87,300 Average of 4 tests 13.57% 13.43% (a) All surfaces with which milk pair or change in the equipment, it is comes in contact shall be smooth, not necessary to test the holder for compli­ Clarification under these conditions ef­ No appreciable advantage in cream vol­ ume is attributable to one proe::ess over readily corrodible metal or unbroken ance with the holding requirement. This fected a reduction of 52 percent of the vitreous material. is done by running water at the pasteur­ bacterial count. the other. Less cooked flavor was noted in milk (b) Easily accessible for cleaning izing temperature with all flow-impeding The effect of high-short and regular pasteurized by the high-short process thag, and inspection. devices open to their fullest extent. The 30 minute (low-long) pasteurization of with the low-long method. No thermo­ (c) Self draining. test is made by injecting a dye or starch milk from the same tank on the cream philic bacteria were ever found in the (d) In good repair, free from cracks solution into a petcock at the holder in­ volume gave the following values: high-short process, thereby offsetting to and corroded places. let and ta·king samples at one second in­ Cream volume some extent the greater number of the[., (e) No threads ·exposed to milk. tervals from a petcock just ahead of the High-short Low-long moduric organisms which survive higfil. (f) Pressure-tight seats on thermo- diversion device. Maintenance of the cladfied filtered short pasteurization. meter submerged openings. required holding time necessitates the use of a positive milk pump geared di­ Average of 6 tests 12.74% 13.09% "If a conclusion were to be written The temperature control shall consist of a dependable automatic thermostat with rectly to a constant speed motor. Any The filtered, long-holding treatment from the information given in this dis­ variable speed gears or pulleys must be cussion it would be that short time high a milk flow diversion device installed at showed a better cream volume than the the holder outlet. The diversion device sea led so that the speea of the pump high-short clarification treatment. temperature pasteurization can be used cannot be changed without the knowl­ with a fair degree of satisfaction, if bt\:e is intended to prevent the forward flow In order to determine the relative ef­ of imperfectly pasteurized milk if the edge of the health officer. quality of raw milk being used is sa£is­ lj fect of clari:fication versus filtration in factory. It will be necessary to keep t'lie thermostat fails or any other irregularity At all times the pasteurized milk must high-short pasteurization, the following number of thermoduric bacteria as lew arises which causes the milk to drop be­ be under greater pressure during regen­ eration than the raw milk to prevent data were secured on milk from the as possible if low cet'lnts are to be se­ low the pasteurizing temperature. The I contamination of the pasteurized milk same vat: cured on milk pasteudzed by the shott entire flow of milk must pass through Cream volume the flow diversion device. In the case with the raw mjjk in case of a leakage of time method. This calls for a g•e~ t the latter. Clarified Filtered amount of lab9ratory pasteurization of of the valve type diversion device, which Average of 5 tests 13.09% 13.83% farmers' samples and a greater amount is the common type, a leak escape groove Satisfactory bactericidal treatment of shall bl! located on the forward flow side The filtered milk showed a better cream of field work to ettminate thermoduric the unit can be accomplished by circu­ volume. organisms from the utensils". of the valve seat and leakage drain com­ lating, hot water at a temperature of 170° pletely outside of the valve body. The F. for five minutes, then dropping the diversion valve is the main safety con­ temperature to the desired operating tem­ trol on the unit and consequently it is perature and running the water on imperative that its construction be such through the unit. As soon as the surge that its proper operation will always be tank is empty, the raw milk is admitted. High Temperature Short Time Pasteurization of Milk assured. At this time the pasteurized water should F. M. Keller, The efficiency of the diverting valve de­ be running over the cooler, or coming Chicago Board of Health, Chicago, Ill. pends . to a large extent on its speed of out of the pipe line open to the atmos­ operatiOn. It must be combined with phere in case a plate cooler is used. The mmtmum time and temperature found that 161 o F. for 16 seconds will the recording thermometer which regis­ "In conclusion, the short-time high for high-short pasteurization, accepted by give similar results. ters temperatures and cut-in and cut-out temperature method of pasteurization is the U. S. Public Health Service Ordi­ The common construction at the pres· r~ponses, and actuated by the same bulb satisfactory providing these construction nance and Code, is 160° F. for 15 sec­ ent time for short-time high-temperat~re system. and operation requirements are observed. onds. Under these conditions, tubercle equipment is the plate type heater w~th 1I'he recorder must meet the require­ There is equipment on the market which bacilli and hemolytic streptococci are milk to milk regenerators. Some JR· me~ts for recorders located in pasteuri­ meets the construction requirements and, killed, and phosphatase tests are com­ stallations also include plate type cooler~ . zation pipe lines. if properly operated, will give results parable to a heat treatment of 143 o F. The generally used holders are of sanl· I 'llhe indicating thermometer should be which are comparable to the low-tem­ for 30 minutes. When holding at 144° tary milk pipe, sometimes calledl "~ubu ocated as close to the recording ther­ perature long-holding method with an F. for 30 rr:inutes is required, it was lar holders". There is also a. umt mometer bulb as possible and also meet adequate margin of safety." Short Time Pasteurization from the Standpoint of the Machinery Manufacturer A. H. Rishoi, Cherry-Bttrrell Corporation, Chicago, Ill. Early in the history of _Pasteurization in the Unired States, questtons arose re­ must be mai~tai?ed to prevent any garding the efficiency of various m~thods age of raw mt!k mto the pasteurized and machines. The results of studtes by PUMP CAPACITY Farrington and Russell in 1898 on t=:as­ If the milk pump delivers lers teurization as applied to buttermak_mg the proper amount of milk, the left the impression that flash pasteunza­ milk will be retarded so thafr it tion was less efficient than the holder main in the holding tube method. Later experiments by Hardi~g necessary, and also reaches the and Rogers in 1899 demonstrated ~hat 10 temperature sooner than it should order to obtain satisfactory bactenal re­ ing still more to the holding time: duction from flash pasteurization, it was impairs the cream line, because necessary to heat the milk to abov_e 15 8 ° at 161 o F. for 16 seconds is F. That milk supposedly pasteunzed by maximum time-temperature ' !.-'"'"" "'<;'"t· the continuous flash process might in fact normal creaming. have been improperly heated may be tak~n On the other hand, if the for granted, for in several eptdemtcs livers more milk than it traced to milk some of the latter was greater difficulty experienced in flash pasteurized milk The result was the milk to the proper temperature, that for a period of years around 1900 by overworking the flow diversion to 1920, flash pasteurization was in many and effecting an irregular bacterial tion. places held in disrepute. Most state laws and city ordinances defined the pas­ Factors which influence pump teurization of milk so as to eliminate any are voltage variation '(sometimes as method other than that which we know as 10 percent in a day run) and as holder type pasteurization. as built up by filrers, .fittings, pipes, The term "high-temperature short time i.fiers, and plates. Also, there is natural wear of a pttmp. The hold pasteurization" was probably first used by Mr. Leslie C. Frank about 1931 milk processed during a day run or 1932. The U. S. Public Health Ser­ corded on recording thermometer vice Ordinance requires heating at 16~ 0 TEMPERATURE CONTROL ".,,.. ...,...... ,, ...,. F. and holding for 15 seconds. The Ctty Some slight temperature of Chicago requires 161 o F. for not less are more or less inevitable, an than 16 seconds. The following require­ ingly some means must be ava ments must be controlled with great ac­ insure that no inadequately heated curacy: leaves the pasteurizing machine. This 1. Flow of milk-pump capacity accomplished originally by the flow 2. Heating water temperature a?d flow stop or more generally now by the 3. Final temperature of the mtlk_ diversion valve. 4. Holding time of the heated mt!k A flow diversion valve may be to be a modified three way valve, In addition, other requirements such as matically activated to direct milk the pressure relationships . between . the a aiven temperature through one raw and the pasteunzed mtlk at van?us and milk at or above that given points in its course through the machme ture through another. The flow adjusted that the flow of milk is diverted _J ,•alve is so c~nst.ructed and ope~~ted it is m 1ts normal positiOn, when the temperature of the milk reaches 0 VI hen 'd f . a specified minimum. The lapse of time a: is, subj ec ~ed to no. ?uts1 eThorces,ch1t from the thermometer response must be 1- the diverting postbon. e me - no greater than 1 second, but it usually ZI-­ of the operation of the diversion acts to divert the flow in 0.32 second and Ocr: · controlled by means of air pres- 5 acts to cause forward flow in 0.49 second. o:::uo 1Briefl y, this may be described as Ow I accomplished by means of a sol­ ...Ja:: lf) z PRESSURE RELATIONSHIPS va.!Ye arrangement in which the In the case of milk to milk regenera­ ~~ ""o or closing of an electric circuit 1--f- u _ - tion, the pasteurized milk must be held <( 01- •• ft .. rnrc:u by bellows which in turn are under greater pressure than that of the a:LL rcU. /I'M cr:2l91.u of the heating medium is operated II) soundness of short time pasteurization ~ o_ UJ ~ ~ .1 somewhali' similar manner. But while I-OJ= ftow diversion valve operates when are the following: ~ (.l)- The cost of machinery is about one­ >- temperature of the milk reaches a if) minimum, the control for the heat­ half as compared to similar 30 min­ rr.edium is operated to control maxi­ unite holding equipment. temperature of the heating medium. On a 4 hour run there is a considerable heating-water temperature control (about 1/3) saving in steam con­ ices and principles upon which they sumption'. rate are represented graphically in Fig- Considering plate machines for short 2. 13riefly, the temperature of the time pasteurizati~n, the floor space ting medium is controlled by means is about 20 percent of that required diaphragm bellows which inflate and for 30 minute hold. with varying air pEessure. Infla­ Plate apparatus giv.es more regenera­ by a partial closing of an tion than tubular heater-holders. nozzle due to the rise in The cleaning time for plate machines perature of the heating medium, par­ is about 40- 50 percent less than ly closes the air supply to the dia­ that · rt;quired for 30 minute hold gm of the steam valve. It also al­ installati9ns: some of the air above the diaphragm Short time pasteurization is effective escape, opening the valve. By a sim- and safe from the public health route deflation of the bellows doses standpoint. steam valve to the heating medium. As yet, high-short pasteurization does not sensitivity of the mechanism is such seem to be practical for small plants, but it responds to fluctuations to less "'""~~ does seem to be logical for a continuous l" F. system of pasteurization. ~ \\) The response of the diversion mechan­ ~ must be ± 0.2 5° F. It must be so J. H. SHRADER. ~Ye\ 204 JouRNAL OF MILK TECHNOLOGY 205 Abstracts ot Technical Papers Presented at Thirtieth Annual Meeting of the American Butter Institute possibility is contamination of the pas­ each of which is capable of causing de­ teurized cream or the butter. The prob­ (Continued from May Issue) terioration in butter. Experimentally, it lem of preventing such contamination is has been found repeatedly that enough complicated because of the many sources organisms are retained when butter is from which organisms can come and the washed with water containing objection­ Bacteriological Defects of Butter great difficulty in keeping certain pieces able organisms to produce the defect ex­ B. W. Hammer of equipment, especially the churns, in a pected on the basis of the organisms in satisfactory condition bacteriologically. the water. In this connection it should be recognized that the wash water and The flavor defects of butter that are with the situation in the spoilage of var­ The complexity of the problem is empha· caused by the growth of organisms i?' it ious food products. Protein decomposi­ the water added in establlshing the de­ sized by the instances in which a serious sired moisture content in butter are rarely are of various types because there IS a tion in eggs, or in meats, is not always attempt is made to control all the sources as finely divided as the water carried into variety of bacteria which can devd?P· brought about by the same organism. from which the pasteurized cream and Some of the organisms produce matenals The study of off flavors in butter is the butter from the cream, which may the butter can be contaminated only to mean that each organism in the added with objectionable flavors from the fat, often complicated by the presence of two find that certain churnings of the butter others from the protein, while still others or more objectionable types of bacteria water has a better opportunity for growth develop cheesiness, rancidity, or some than if it were in a comparatively small use a constituent pr·esent in a relatively in a sample. Plant conditions which per­ other defect under commercial conditions. low percentage, such as the lactose. Cer­ mit the entrance of harmful bacteria 'into water droplet. Water that is at all ques­ A source of objectionable organisms tionable should be treated in some way tain organisms actively attack two of the butter often are not selective enough to in butter th~ t is receiving increasing at­ butter constituents. limit the contamination to only one type. before it is used to wash butter. The tention is the water us·ed to wash butter wide application of chlorination to gen­ Ordinarily, a bacteriological flavor ~e ­ In this conaection it should be noted tha t< since it has been the source of the causa­ eral water supplies suggests its use in fect of butter can be reproduced by m­ many of the bacteria which contaminate five organisms in various outbreaks of oculating the butter into well pasteurized butter have no effect on the flavor. They connection with water intended for wash­ bacterial spoilage. A sample of water ing butter. Such treatment has been cream and then churning. Such attempts may grow exte~sively and still not pro­ may contain several kinds of bacteria, are more likely to be successful if the duce objectionable changes becaus·e of the found satisfactory in numerous instances. various factors influencing the growth of nature of th.e products formed. bacteria in butter are recognized in mak­ Even with the uncertainties involved, a ing and holding the butter. When a _de­ more or less definite classification of ilie fect is reproduced in this way, particu­ bacteriological flavor·'aefects of butter has larly when it is carried through succes­ been developed by . butter judges, and a International Association of Milk Sanitarians sive lots of butter, the action of organisms number of rather definite defects are The chairmen of the several com­ is clearly established. recognized. Sanitary Control of Ice Cream, mittees of the Association is announced F. W . FABIAN, East Lansing, Mich. In general, a flavor defect due t? bac­ Theoretically, coo-trol of the bacterio­ as. fo llows : teria is a changing thing and IS not logical defects of butter is relatively Laborl\tory Methods, rapidly developed to a certain point at simple. The various bacteria responsible Communicable Diseases Affecting Man, C. A. ABELE, Montgomery, Ala. which it remains stationary. At first the foc them are easily killed by heat, so P. B. BROOKS, Albany, N. Y. Education and Training, defect is sl ight, and then as the growth that the usual pasteurization exposures L. C. FRANK, Washington, D. C. of the organisms continue it becomes destroy them, and if the pasteurized Sanitary Procedure, more pronounced. Later, the defect may cream and the butter are protected £rom W. D. TIEDEMAN, Albany, N. Y. Resolutions, even become less intense. The situation contamination the butter should be ~ree E. KELLY, Washington, D. C. Dairy Farm Methods, is especially confusing with certain or­ of the organisms that ·cause defects under Florida Committee, ganisms that attack two of the butter ordinary conditions. Practically~ . how· F. D. HoLFORD, New York, N.Y. H. N . PARKER, Jacksonville, Fla. constituents because one type of decom­ ever, there are various opportun ~ t1es for position is the more conspicuous at first a break in the chain of protectiOn that and the other is the more prominent later. modern manufacturing methods sh~uld Various organisms that attack both pro­ give butter. One possibility is ine~ctent tein and fat may first give a defect sug­ pasteurization of the cream. ~htle the Enlarged Field for Mr. Frank gestive of protein decomposition whereas exposures intended to be used w1th cream later the defect is indicative of a break­ are never so low that a survival of ob­ ~he former Sanitation Section of the National Institute of Health except the down. jectionable organisms is probable, th~ ~nmenta l pasteuriza~ion plant,. has ~e7~ combined with the former 'Engineering A specific off flavor commonly can be may be contamination with under-he~ t th. tio~ ?~ the Domestic Quaranttne DIVIsiOn to form a new Sanitation Section in produ~ed in butter by more than one cream because of inadequate by-passtng, IS Dtvtslon wi&h Mr. Leslie C. Frank as Section Chief. kind of organism. This is in agreement leaky valves, dead ends, etc. Another 206 JOURNAL OF MrLK TECHNOLOGY 207 JOURNAL OF MILK TECHNOLOGY Association News Official Publication of the Milk Section of Texas Public Health International Association of Milk Sanitarians Michigan Association of Dairy and Association (Association Organized 1911) Milk Inspecto-rs Editot·s One of the schools of the second an­ nual Texas Milk Sanitarians' Short Course The Annual Summer Training Confer­ W. B. PALMER, Managing Editor ]. H . SHRADER, Editor ence for Dairy Inspectors will be held at Orange, N. ]. East Orange, N. J. was held at A. & M. Coiiege, April 24, Michigan State Coiiege, East Lansing, on Associate Edito1'1 25, and 26, 1939, under the auspices of July 13, 14, and 15, 1939. Lecture ses­ c. A. ABELE M A HEINZMAN ERNEST KELLY M. E. PARKER Texas A. & M. Coii-ege, the Committee Montgomery, Ala. ' Ve~tura, Cal. Washington, D. C. Chicago, lll. on Milk of the Texas Public Health As­ sions, held in the forenoon, will cov·er SARAH V . DUGAN J. A . KEENAN P . F. KRUEGER G. W. PUTNAM sociation, and the Texas State Department (1) ice cream sanitation, (2) production Louisville, Ky. Boston, Mass. Chicago, Ill. Chicago, Ill. of Health. of quality butter, (3) milk plant ·equip­ J . G. HARDENBERGH c. K. JoHNS H . N. PARKER F. M . SCALES ment, ( 4) licensing dairy inspectors, and Plainsboro, N . J, Ottawa, Canada Jacksonville, Fla. New York, N. Y. Besides the lectures that were given (5) farm sanitation. H . R. THORNTON each day on the subjects' relating to milk Edmonton, Alberta. Can. and milk sanitation, laboratory facilities Laboratory courses in the afternoon will THE JOURNAL OF MILK TECHNOLOGY is is- other reading Shatedial should be addressed to tht have three sections, and wiii deal with sued bimonthly beg!nnin& with bthe Ja ~u~ryp~bfu~~d 6~~~~~. JN.\ ra er, 339 Springdale Avenue, EISI and competent instruction were provided Each volume compnses SIX. n.um ers. .1 IS . • each afternoon for those desiring actual {1) use of microscope, (2) plate counts by the International Assoctatton of Mtlk Samtanans, MembeTihip and Dun: Active and Associate 'M:e.m,. and their interpretation, (3) phosphatase and is pri nted by The Chronicle Press, Inc., Orange, berships in the Association are $5.00 per yea ~. l'bis demonstratiqn and practice on methylene test, ( 4) methlyenc blue and resazurin N. ].,1 U. S. A. . includes all issues of the JCondensed Milk Industry." dent, Dr. M. B. Starnes, Dallas, Texas; Sttrt college, and papers were presented as The fall meetings of the Society will begin on Pre1idmt E. J. O'Connell, Holyoke, Mass.; Vice­ TreaJurtr, W. E. Roberts; State Health Dept., Allllii, Pmident, j, B. Enright, Fitchb'\rg, Mass. C; Secbrt!dry­ Texas. follows : "Recent Changes in the U. S. the third Tuesday of September. Treautrer, R. E. Bemis, 24A Ctty Hall, am rt ge, MISSOURI ASSOCIATION OF MILK SANITAIUANJ Public Health Service Milk Code" by Dr. Mass. 0. F. GARRETT, Prtiidmt, Joe Moffatt, Sedalia, Mo.; V~

The palm-fringed fairways and velvet greens of sporty Pohte links at Ponte Vedra Beach, near Jacksonville, Florida, will be the the greatest links battle in the history of the Southeastern P.G.A. '-'U.tuUJI'Il ship September 20-22, judging by the record number of top-flight already entered. The 1938 Southern Amateur Championship held June was the most successful in the history of that classic. The island ninth green nestles in a lagoon near The lnl'l( brilliant new hotel that has already become the talk of the smart resort world.

Rates of Hotels in Jacksonville, Fla . ...,. HOTEL MAYFLOWER (Headquarters) $2.50 to $3 .50 per day- single rooms $4.00 to $5.00 per day- room with double bed $5.00 to $6.00 per day- room with twin beds All rooms equi-pped with private batli HoTEL WINDSOR $2.50 to $3.00 per day- single room with bath $4.00 per day- double room with bath, double bed $5.00 per day-double room with bath, twin beds HOTEL SEMINOLE l HOTEL GEORGE WASHINGTON }- same rates as above. THE RoosEVELT J Twenty-eighth Annual Meeting

October 25 - 271 1939