JOlJRNAL of MILK TECHNOLOGY

September, 1939 Number 5

Editorials upinions and ideas expt·essed in ~a~ers and editorials are those_ ot the resp:ctif,e authors. '[he expressions of the Assocratron are completely recorded m rts transacttons.

· 1•11 See You at Jacksonville If you fail to attend the International Association of Milk Sanitarians annual meeting in Jacksonville, Florida, October 26-28, you are bound to miss a golden op­ portunity to spend three of the most entertaining and educational days of your life. By attending this meeting you will not only have the opportunity of greeting td friends and meeting new ones, but you will also be privileged to participate in a prosram d evi s ~d to ~eet .your n.eeds, whether you ~re .interested in. ~ilk from the undpoint of tts offioal, mdustnal, regulatory, qua!tty control, nutntwnal, or tech­ nical asp,ects. "Nutritional Value of Milk", "Bangs Disease", "Plate Count for Measuring Quality", "Certified Milk", "Communicable Diseases Affecting Man", and many other equally important subjects will be discussed by eminent authorities, and you will aed the opportunity to participate in round table discussions should you have I especial problems or questions which you desire to have dicussed or answered. Since t! this meeting is international in scope, many interesting contributions are expected from authorities and friends from our neighboring P~n.-American countries. As a regular feature of the meeting, field trips will be arranged to points of in­ I tere& in the vicinity of Jacksonville and St. Augustine, and the program of enter­ tainment wi ll be replete with attractions and functions which will not cripple your ket book. lf you des ire to learn more about milk and milk products, want to make contacts tlut wi!I be invaluable through the remainder of your life, and would like to spend three of. the most enjoyable and entertaining days imaginable, you will meet me at the International Association Meeting in Jacksonville, Florida, October 26-28. YOU NEED THE INTERNATIONAL ASSOCIATION AND IT

V. M. EHLERS, President. non-specific, and undependable, so that reliance on their reactions does not •• ,..,..,.,,.,,., afiO IVliiK \...Ontrol the confidence of the farmer. Moreover, many producers, when ordered to Laws designed to regulate public milk supplies contain provision,. that milk f mastitic cows, prefer to sell these animals to other dairymen rath_er than 0 be produced by healthy animals. An ideal which alert milk sanitarians are ch r Thus an attempt to reduce the incidence of mastitis by drastiC regu- to attain is a milk supply produced by animals with healthy udders. Both the thebut e. b " ht es may spread the infection to other herds. Human nature emg w a requirement and the ideal involve the problem of mastitis. The execution f rneasur d 0 . Id seem that the only way that this situation could be prevented woul js It WOU . • requirement is not a simple matter. Milk sanitarians of high professional ' h ar-marking such animals and paymg the farmer some compensation as throug e . · · h lhlds h h - ments, long experience, and public health ideals have different ideas as to the e tuberculosis eradtcatlon program. In ge~eral, . thts sc oo_ o t at t e . ap effective and desirable program to be used. th the farmer should be directed to enlist hts cooperatiOn and to convmce The facts in the situation are recognized by all. Mastitis in dairy cattle is ach to "t ·s to his advantage to dtspose· of such cows. T o at·d htm" tn· the con t co I • that 1 t . spread. This pathologic condition is always inimical to the economic prclelu:ctir\n 01 · mastitis the strip cup and palpatiOn of the udder are dependable tests. chroruc , . . 1 d "1 milk and sometimes to the health of the consumer. A cow with mastitis is a r himself can use the strip cup at every mtlkmg, or at east at y, so as to e farmer . · · ( 1 to a dairyman. Such a cow eats as much food as a healthy, normal one but does ect the active cases. If this can be supplemented by a phystca 1 exammat10~ pa - produce a normal yield of milk from the infected udder. The segregation and . ) b an expert who can advise the farmer as to methods for reducmg the tiOn y · dSh ment of such a cow costs labor and money. Such udders are generally shedding read of udder disease, then_ encouragm~ progress may be expecte . uc an ap- numbers of organisms and are likely to spread the infection. These c;)1Jarters oach is likely to enlist the acttve cooperatiOn of the farmer. considerable fibrosis with a corresponding reduction in milk secretion. pt 'Flle other group believes that public health considerations must take precede~ce. one phase of the problem is economic. int of view provides the stimulus to utilize any or all present means of dtag­ Moreover, there is a bewildering variety of tests for the diagnosis of pof detecting cows with mastitis and eliminating them from the dairy herd. It IS or . . . . . Their very multiplicity is eloquent of the fragmentariness of our knowledge. ogni2es that none of these chemic~!, bwchemtcal, and mtcroscoptc tests are mclu- tests to diagnose this condition are as definite as the tuberculin test for • •ely and exclusively completely speofic and depen~able . How_e~er, they serve _as a tuberculosis. Diagnosis is further complicated by the fact that the chemical and ·d sorting test to reveal those milk samples whtch are susptcwus, and to duect chemical picture of the milk changes from milking to milking, so that a =~tion to those animals which should be examined p~ysic~lly . Any found t~ be finding is no guarantee of freedom from infection. Typical reactions fo r iofected are ordered to be excluded from the dairy herd, somettmes from the premtses, catalase, pH value, etc. are frequently obtained from quarters fre~ from an.y recoar1ia liling Joss to the farmer. An additional economic loss has ~en reveal~d by udder pathogens ( 1), and negative reactions may be obtaiP,~ from some Brooks (3) whereby the public are involved. An outbreak ?f mtlkborne dtsease cases (2). The elimination of all cows whose milk is positive to any of these ulting from mastitis in a small community was costly to busrneu. T~e ~onetary would probably create a decided milk shortage. far exceeded the total appropriation for an entire milk control orgamzat10n. Another aspect of the matter is that of the public health._ Some types of :c.'!Stic exclusion of mastitic animals from a milking herd may introduce a regu­ titis are caused by microorganisms which are pathogenic to 11'1!tn; such as those ory problem of tracing the disposition of the excluded animal. To this may be ing septic sore throat, erysipelas, and scarlet fever. Although the number of ded the resentment of the unconvinced farmer. It is doubtful whether the cause cases in relation to the total number of infected udders is very smal ~ the an improved public health is advanced in such a ci~c!lmstance unless the affected hazard is very real to the victims and potentially so to the public at large. is cured or traced, and the farmer "sold" on the reasonableness of the _procedure. Associated with this aspect is the fact that most competent obser-vers agree He becomes a booster of the program when he is shown that he is better off. After cows whose milk frequently shows clots, flakes, or other abnormal features he economic stimulus was the basis for the great success of the tuberculosis eliminated, because this kind of milk is unacceptable for human consump tion. dication program. It is newly evident in the campaign against Bang's disease. It abnormal milk from a diseased udder is obnoxious, especially when it rnn1 t.air1 ~ uld be invoked in the control of mastitis. f!ammatory secretions of va~ious kinds, together with high cell content and What school of thought do you adhere to? We should like to know your debris from infection. s. Write us . Conscientious and intelligent milk sanitarians are faced with the question, ]. Agr. Research, April 1939. far shall I go in attempting to eliminate mastitis, and what shall be the basis An evaluation of some of the tests used in detecLing mastitis in dairy cattle. A. C. Fay, deciding what animals to eliminate?" ]. Milk Techno/. 1, No.4, 38 (1938) . One group holds that a mastitis control program should be based mainly A study of milk-borne epidemics. P. B. Brooks, Ibid. 2, 168 (1939). economic considerations. They hold that chemical and biochemical tests are J. H. S. JoURNAL OF MILK TECHNOLOGY 2 13 212 .. ~ Pasteurized Cream Production Coordinated With q Simultaneous Milk Processing ~

~ ~ W. B. Palmer ~ ·t " ::- Exemtive Officer, Milk Inspection Association of the .li ~ 0 to .."> ~ Oranges and Maplewood, N. J. tq

A pasteurized cream supply is as im­ TABLE 1 portant from the public health and tech­ Bacteria Counts of Bottled Cream Separated from Pasteurized Milk ~ nological points of view as a pasteurized (Samples taketl at time of delivery to consumer) ;; milk supply. Heretofore it has been 19)8 ~ the practice and actual requirement that Milk Light Heavy -!:!... 2,000 9,000 cream be pasteurized subsequently to 500 ~ ~"' 16,000 separation. This procedure has been 2,000 ···················· 12,000 ~ "' 600 ...... 5,000 1,000 ..t" <>.. deemed necessary to insure against the 2,000 1,000 ~ ~ '< !1- "~ 1,000 't • 4,000 ):> possible contamination of the product dur­ 3,000 2,000 ~ ~ ~ ing the handling of the milk and the 2,000 4,000 6,000 .."~ ~ ...... 100,000 100,000 ~ ~ production of the cream. In plant prac­ 2,000 ~ 400 1,000 :>,00() "' ;::; tice this means that a dual system of p::t.>­ 9,000 11,000 ...... 2),000 ~ teurization of milk and of cream must be 1,000 5,000 5,000 " 4,000 .-< - ~ operated. This involves additional ex­ 1,000 ···~ ------·-·-· 2,000 1,000 1,000 ~ · ~ '~ ...... : 1'1 ~ pensive equipment together with added 1,500 .. "~ rx: ..,"' 1,000 ...... 10,000 15,000 : ~ ;:> maintenance, increased length of plant .." 2,000 2,000 1,000 't 0: ~ " "- operation, and additional labor. All milk 1,000 .. ... : ~ P::'t) 400 1,000 ~ "' ~ . plants producing their own cream have "' 't.; ~ 1-?59 "'"I> u" ~ -~"' 4,000 . -::; thus been subjected to unnecessary ex­ 100 ···················· . 6,000 ~ ~ jt 1,000 ...... 5,000 2,000 .;; pense. However, such practices and re­ 3,000 ::> quirements do not necessarily protect the 100 .... ··············· 1,000 ~ 1,000 -·- ······--·····--· 2,000 1,000 2,000 ultimate product. 1,000 ...... 1,000 ~ 1,000 ...... , 1,000 1,000 IMPROVED CREAM PRODUCTION t,OOO ~ PROCEDURE 500 ···················· 1,000 II 2,000 ...... 2,000 3,000 "' 11 It is obvious that if milk, pasteurized 400 ...... 2,000 2,000 s !:; for bottling, is also used for cream sep­ 1,000 ...... 1,000 1,000 11 "~ aration at the time the milk leaves the Note: Milk plated 1 : 100 and 1 : 1,000 .-::;. pasteurizer, the cream is certainly pas­ Cream plated 1 : 1,000 and 1 : 10,000 .,. teurized and is as safe and wholesome Cream processed under this method is r.t.l"' as the milk from which it was produced. indistinguishable in appearance, and v~­ Furthermore, it is also obvious that if the cosity, contains less sediment, and IS separa:ted cream is piped, cooled, and superior in flavor to cream processed by bottled without exposure to any human the older method. contamination or handling, it is of equal EQUIPMENT ARRANGEMENT sanitary quality to the bottled pasteurized milk itself. The arrangement of equipment tp p_ro­ A process involving these principles duce pasteurized cream under this ~~­ was devised by the author in 1931. Upon proved system is shown in figure 1. Wtth our official recommendation, six plants modifications, this same principle can be adopted and have been successively op­ applied to plants operating gravitr-llow erating under this process. This is at­ pasteurizing and bortling systems wtth~ut tested by the bacteria counts shown in milk pumps, or to plants operating w1th air-tight pressure cream separators. table 1. 215 In explanation of operation of this separator, with the result that the milk system, the following is given as exam­ flow is thereby decreased through the ple. If the plant schedule is to pasteur­ balance of the milk cooler to accommo­ ize and bottle 100 cans of milk, and is to date the bottling of pints and half-pints The Sterilizing Quality of Chlorine Solutions separate for cream 50 cans of milk, mak­ of milk simultaneous-ly with cream sep- ing a total of 150 cans to be pr~cesse?, arating and cooling. . Under Different Conditions the 150 cans of milk are pasteunzed m Of further interest and value, there IS F. M. Scales and Muriel Kemp the one operation. There are optional the possibility of applying this system. t? a methods for operating this system. One Sheffield Farms Research Labot·atory, New York, N . Y. high-temperature ~hort-~9!d pasteur~zt.ng method is to pasteurize, cool, and bottle unit. To accomplish thts, a take-off l ~ne the 100 cans of milk, then shut off the The potency of a chlorine solution for ing agent as potassium permanganate ice water or refrigerant section of t.he could be installed in the cooler section sterilizing is measured by the quantity of whereas chlorine in alkaline solution (i. e. milk cooler, thereby cooling the remam­ where the chilled pasteurized milk has "available chlorine" present. This "avail­ hypochlorites) is less power.ful than fer· reached a temperature of 80-85 o F. Such ing 50 cans of pasteurized milk to 80-85 o able" or "active chlorine" is not neces­ ric chloride which is not a vigorous agent. F. and diverting it to the separator, and chilled pasteurized milk would be di­ sarily free chlorine but more often the As the chlorination of the amino acids then finally cooling the cream over a verted to the cream separator. This unsta:ble hypochlorous acid or its sodium already described is an oxidation pro.cess, cream cooler to 38-40° F. Another would allow decreased milk flow through salt. A more correct designation of the work of Rideal and Evans furnishes method is to install a take-off milk line the balance of the cooler section and into "available chlorine" ·is that unstable sub­ the data that explains why the hypo­ from the internal tubular cooler section the milk bottler for pints and half-pints stance in solution which, either as free or chlorite in acid solution (hypochlorous at which the pasteurized milk is cooled without altering the rated flow of the combined chlorine, has an active affinity acid) should be a superior germicidal to 80-85°F. and to divert the milk to the machine. for the proteins in the cells of micro­ agent. organisms. This chlorination is incom­ In this investigation it was necessary patible with the life of the organisms. to study hydrogen ion control, the cul­ The active chlorine unites with the amino tures to be used, the most practical meth­ acids df the proteins so that it replaces New High-Short Pasteurization Research Program od for determining bactericidal quality, the hydrogen combined with the nitro­ and germicidal effects at varying pH Timely and in keeping with the .perti- pasteurization will be studied under both gen and forms a chloramine. This lat­ values, temperatures, and times ( 2) . ter substance is a germicide. Other re­ nent editorial relating to the bacteno!ogy plant and laboratory cond.itions .. In ol'der HYDROGEN ION CONTROL t to have a tie with. the tmmedtate past, actions may also take place to render some of short time-high temperature pas eun- both the new and the old standard nutri­ of the chlorine inactive. In order to discover some of the fund­ zation as published in the July is~ue ?f amentals concerned in sterilizing with y he Journal of Milk Technology 1t. ':"'ll ent agars will be used. The present work was planned for the purpose of improving the potency of chlorine solutions, it became necessary to interest readers to know t h at a en t tea I The counsel and cooperation of fiau ldthor- f prepare a series with ·pH values from 6.0 comparative bacteriological study on ~he iti·es in the industry and in the e o available chlorine so that satisfactory re­ sults may be obtained with weak solu­ to 11.0. Such solutions were made by pasteurization of milk by the holdmg public health havtll··been solicited in the dissolving 75.68 grams of a neutral lime method and the short time-high tempera- general plan and execution of this study. tions. Specifically a test was made of the germicidal quality of hypochlorous acid solvent (hexametaphosphate) in 3.785 ture method of pasteurization is un.der The work is being done in some ten liters or oqe gallon of distilled water and way at this time. This researc~ ~ro1ect plants l~cated i~ .New York an~ €?n· as compared with neutral and alkaline solutions of hypochlorite. then adding 18.92 grams of H. T. H.* has been inaugurated by the datry mdus- necticut m proxtmtty to Yale Umv:emty. Approximately 56 mi. of this solution Rideal and Evans ( 1) in their report try and the dairy machinery industry and The sponsors of this study are: diluted to 3. 785 liters gave a solution of is being conducted by Dr. T. W.· Work- Dairy Industry ... of 192 1 laid emphasis on the suggestion 50.0 p.p.m. of the senior author in a publication of man in the department of bactenology ~t Borden Farm Products DlVlston or A reagent to convert the alkaline hypo­ Yale University, New Haven, Connect!- The Borden Company . 1912 that the oxidizing power of hypo­ chlorite solutions is particularly marked chlorite solution to the acid range was cut. Dairymen's League Cooperattve A · w~en they are made acid. next selected. Mono sodium phosphate This critical investigation of the .two sociation was finally chosen for the purpose. methods of pasteurization wil_l include Sheffield Farms Company [ his is shown in the oxidation poten­ tial series which they give (see table 1.) The chlorine solution prepared as des­ in part: A comparison of bact~r.tal counts, Dairy Machinery Industry . cribed with an available chlorine content a systematic study of the survlVlng organ- Cherry-Burrell Corporatton TABLE 1 of 50.0 p.p.m. had a pH* value of ap­ isms the determination of the thermal Creamery Package Mfg. Comgany Potassium permanganate ____ Eh =+1. 48 volts proximately 8.0. It was found that the Chlorine in acid solution___ " +1.39 " death times of the thermoduric organisms De Laval Separator Company = pH value of this solution could be ad­ Cllromic acid ------·--·--·----- " = + 1.12 encountered, and an attempt at the prac- Taylor Instrument Company Ferric chloride ----·-- ·------" = +0.96 justed to that desired for the germicidal tical identification and control of ther- York Ice Machinery Mfg. Gompany Ollorine in alkaline solution " = +0.86 tests by the additions shown in table 2. moduric organisms in the raw milk sup- A. J. PoWERS, Chairman. 'rhe table shows that chlorine in acid plies involved. The two methods of • This powder just happened to be a convenient solution is about as powerful an oxidiz- one for our purpose. Almost any other powder or chlorine solution may bo used equally well. 216 CHLORINE STERILIZATION jOURNAL OF MILK TECHNOLOGY 217

TABLE 2 They were nearer to those of the Rideal­ of course varied but the trends were the Aditt.rtmmt of Hydrogen Ion Concentratio11 Walker procedure. Two 5 7 and 10 same. minutes seemed better i~ter~als' for this Available Original Additions Resultant GERMICIDAL STUDIES AT VARYING PH pH work. At the end of the exposure time chlorine pH per gallon VALUES, TEMPERATURES, AND TIMES 1 ml. was withdrawn and added to 10 p.p.m. The results of the exposure of the S. 50.0 8.0 0.19 gram NaOH 11.0 mi. of fresh broth, and incubated in the 8.0 culture to chlorine solutions of 50 50.0 8.0 0.00 usual way at 3 for 48 hours. auretts 7.0 r c. 50.0 8.0 0.45 gram NaH2PO.+H20 p.p.m. of available chlorine under the 6.10 grams NaH2PO,+H20 6.0 For plating examinations of germici­ 50.0 8.0 dal power, the test organisms grown on c~nditions . of different pH values and different times of exposure at different All readings of pH values were made with a Beck· chlorine solutions. One, a mixed · cul­ an aga~ plate were suspended in 100 ml. man pH meter and with glass and calomel elec· temperatures are shown in table 4. trodes. ture, was obtained by adding some milk of stenle tap water and shaken in the to a dirty milk botle and incubating at usual way. Fiv·e ml. were added to 45 A chlorine solution containing 50 p.p. An examination was made of the effect 3 r c. for 6 hours and then plating. ml. of the chlorine solution which had m. of available chlorine at a pH of 11 of temperature on pH value. Readings The resulting surface growth was sus­ previously been raised to the tempera­ did not sterilize the culture when held were recorded at temperatures from 50° pended in 100 ml. of sterile tap water, tu.re for the. test. . After shaking the con­ at any temperature from 50° to 90° F. to 90° F. inclusive, in ten degree spans, replated, and carried in this way for stock. tamer ten times, It was placed in a water for a period up to and including 10 min­ as shown in table 3. This culture proved as resistant in gen­ bath at the ·specified temperature and ex­ utes. Some tubes (not reported here) Chlorine in the hypochlorite form is eral as S. auretts No. 5 38. The latter posed for the intervals indicated. At the were held for 15 minutes at 90° F., but relatively unstable and volatile especially was obtained through the kindness of the e~d of each, holding period, 1 ml. was the results were the same. At a pH of when the solution is acid. In order to Hygienic Laboratory, U. S. Public Health withdrawn after shaking the bottle ten 8, the cultures held at 60° F. up to 90° determine the effect of changes of tem­ Service, Washington, D. C. In tests £or. times and placed in a petri dish to which F. for 5, 7, and 10 minutes were sterile. perature upon the chlorine content, solu­ resistance, both the mixed culture and had_ been .added some sterile 1 percent At 50° F., the duplicates in the 10 min­ tions containing 53.4 p.p.m. of available S. attreus grew after 5 and 10 minutes sodmm th10sulphate solution*. Standard ute set were also sterile. At a pH of 7, chlorine at pH values of approximately exposures to a .1:70 phenol solution but agar was added in the usual way and al! the cultures held for 2, 5, 7, and 10 6 and 11 were tested for chlorine con­ gave only faint growth alter 15 minutes the plates incubated for 48 hours at 3 r mmutes were sterile at all temperatures tent after holding at 50° and 90° F for exposure. Both cultures failed to show C. The determinations were all run in except one fpr 2 minutes at 60° and 70° 30 minutes. Neither the acid nor alka­ any growth in a 1 : 60 phenol solution triplicate. F. and two for the same time at 50° F. line solutions held at 50° F. lost any when exposed for ~he three periods de- The data presented in all the tables At a pH of 6, all cultures held from 5 chlorine. At 90° F. during the same scribed. ' . have been verified by repeated tests ex­ to 10 minutes at all five temperatures time, the solution at a pH of 6 lost 0.87 cept where otherwise noted. Numbers were also steril ~.. At _90" F., both cul­ p.p.m. of chlorine which is negligible, METHODS OF DETERMINING tures held for 2 minutes· were sterile. One I BACTERICIDAL QUALITY I and the alkaline one showed no loss. • Wher~ 2 or 5 p.p.m. of available chlorine were of the duplicates held for 5 minutes at The germicidal value of the solutions us~d In the test, 0.3 ml. of the 1 percent sodium The chlorine contents were determined thwsulphate was taken; if 10 or 20 p.p.m. were 50° F. showed growth. The others at by the usual titration method which con­ was determined ac"Cording to the Federal used, 0. 5 ml. of the thiosulphate was employed · this p[I for 2 minutes grew scantily ex­ and when there ~er~ 30 or 50 p.p.m., 0.8 ml. wa~ sisted of adding the chlorine solution to Department of Agriculture method for added to the petn d1sh . cept at 50° and 80° F. a potassium iodide solution that had determining the phenol coefficient but been acidified with hydrochloric acid. The with the following modifications: f our TABLE 4 in liberated iodine was titrated with either ml. of the inoculum were suspended Germicidal results with S. aureus tenth or hundredth normal sodium thio­ 100 ml. of sterile tap water. Five ml. of exposed to 50 p. p. tn. of availavle chlorine sulphate depending on the concentration this suspension were added to 45 ml. of Temperature 80° F. 70° F. 60 ° F. of the chlorine. the chlorine solution which had been Exposure in CULTURES raised to the temperature for the test. Minutes 2 5 7 10 2 5 7 10 2 5 7 10 2 7 tO 2 5 7 10 Two cultures were used in determining The times of exposure to the germicide pH the germicidal quality of the different also did not follow the F. D. A. method. 11.0 5+ 5+ 5+ 54· 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ 5+ s+ 8.0 0 0 0 0 1 + 0 0 0 5+ 0 0 0 5+ 0 0 0 5+ 5+ 1+ 0 TABLE 3 5+ 0 0 0 1 + 0 0 0 5+ 0 0 0 1 + 0 0 0 5+ 5+ 3+ 0 Chm1ge in hydrogen ion concentration 7.0 0 0 0 0 0 0 0 0 5+ 0 0 0 0 0 0 0 5+ 0 0 0 with temperatttre in chlorine solution of 53.4 P. P. M. 0 0 0 0 0 0 0 0 0 0 0 0 2+ 0 0 0 5+ 0 0 0 6.0 0 0 0 0 5+ 0 0 0 1 + 0 0 0 1 + 0 0 0 5+ 1+ 0 0 80° F. 70° F. 60° F. 50° F. Change 90° to ~o· 90° F. pH 0 0 0 0 5+ 0 0 0 1 + 0 0 0 1 + 0 0 0 3+ 0 0 0 pH pH pH pH pH +0.40 Control 1,800,000 per milliliter 10.90 10.50 11.30 11.20 11.30 +0.2~ The ~uxu r iance of growth is indicated by the following figures : 7.90 7.96 8.15 8.15 8.15 6.90 6.99 7.00 6.90 +0.05 0 +:No growth 2+ = Light 4+ = Heavy 6.85 +OJO 1 - Trace 3+ Medium 6.20 6.20 6.20 6.39 6.5Q = 5+ = Very heavy .:.. .LU LHLORINE :,TER!LIZATION JoURNAL OF MILK TECHNOLOGY 219

The results with the mixed culture pH value so that the killing was only and 53.1 p.p.m. The latter was divided Section of the International Association of were very similar to those with S. aut·em 3 7.5 percent. into three parts: one re-ceived an addition Milk Dealers in 1930 and also published except that it showed a little more growth In another t-est, an original count of of 1.25 grams of NaH2P04 +H2 0 per with an illustration of the frame in Food at a pH of 7 and 8. 21,000,000 spores per mi. was exposed to gallon of solution, another part received Industries, March 1931. The fixed areas These tests indicate that sterility is ob­ a chlorine solution containing 50 p.p.m. 1.5 grams of this salt per gallon, and were obtained by means of rigid steel tained in a shorter time with a solution at a pH of 6 for 3 and for 5 minutes. the third received no addition. Readings wire frames with handles. There was an at a pH of 6 or 7. The results also Seventy-one and nine-tenths percent of were then made on the pH values of the opening one foot square within each show that temperatures from 60° to 90° the organisms were killed in 3 minutes five solutions. The results are shown in frame and this area was divided by wires F. are satisfactory, but that 80° and 90° and 99.89 percent in 5 minutes. .&. table 6. into four equal parts, six inches on a side. TABLE 6 F. produce slightly better results. slightly longer exposure would probabLy f{ydrogm io11 concentration of chlot·ilze solu­ For these examinations* the foot square Since a pH of 6 and 7 showed a sat­ give complete sterility. tious prepared from a commercial 15% areas were used for all swabbings. Twelve isfactory increase in the potency of the sodium hypochlorite solutio11. areas were thus swabbed on opposite sides GERMICIDAL POWER OF 50.0 P.P.M OF chlor.ine solution, the germicidal quality Available Addition of pH at of the storage tank. As soon as the AVAILABLE CHLORINE UNDER of different concentrations of chlorine at No . chlorine NaH2PO,+H:O 22 o C. swabbing of a square foot was completed, PLANT CONDITIONS p.p.m. grams per gal. the former pH value was next determined. the swab was dropped into 10 mi. of di­ The results obtained are shown in table 5. In view of the fact that most Board of 1 255.0 0 10.60 lution water and hurried to t-he laboratory Health regulations require that a solo,. 2 106.0 0 10.35 53 .1 0 8.35 for plating. When the dozen areas on TABLE 5 3 tion for spraying shall have an available 4 53.1 1.25 6.35 opposite sides of the tank had been sam­ Ge1·mifidal ,·esults with differmt chlo1·ine con­ chlorine content of 250 p.p.m. after it 5 ( 3.1 1.50 6.30 cenll·ations at different pH values. pled, unswabbed areas were sprayed with All exposures for 3 minutes. has performed the sterilizing process, any The comparison of the germicidal value the chlorine solution containing 106 p. Chlorine Mixed practical application of the results ob­ of the solutions was first tested under p.m. with a pH of 10.35. At the end Strength pH S. aureus culture tained here would have to be based on a plant conditions by spraying a stainless of 2% minutes exposure, the area was 0 7.0 9,000,000 7,000,000 comparative test of the effectiveness o.£ an steel, insulated storage tank (capacity 425 quickly wiped and the swab dropped into 2 6.0 8,300,000 6,700,000 alkaline chlorine solution of this strength cans), that had been washed and rinsed 10 ml. of dilution water containing 0.01 5 6.0 2,200,000 2,000,000 with an acidified one containing approxi­ 10 6.0 1,000 1,000 with cold water, with the alkaline hypo­ gram of sodium thiosulphate. These sam­ 20 6.0 750 800 marely 50 p.p.m. chlorite solution containing 106.0 p.p.m. ples likewise· were taken to the laboratory 30 6.0 130 380 Chlorine solutions for spraying pur­ of available chlorine and an acid one for plating. Then similar areas were 30 11.0 1,300 3,800 poses are frequent!y. prepared from those 50 6.0 130 130 containing 53.1 p.p.m. of chlorine at a sprayed with the chlorine solution con­ purchased with a chlorine content of 1J5.0 pH of 6.35. Fixed areas were carefully taining 53.1 p.p.m. at a pH of 6.35. These results show that at pH 6, 50 percent. Such solutions when diluted to sampled by swabbing before both treat­ After the same exposure as the previous p.p.m. of available chlorine in 3 minutes 255 p.p.m. , the strength used in prac­ ments to obtain an average count per set, the areas were similarly swabbed and kills from 99.9981 percent to 99.9985 tice, have a pH value from 9.1 to 11.3. square foot of the untreated surface. The plated. 1Platings were made in quadru- percent of the organisms present. A A solution for,Prculating in equipment · procedure used for obtaining these counts usually must have an available chlol'ine slight increase in time, as indicated by was described by Scales and Russell (3) • The authors wish to acknowledge with apprecia· the results in table 4, would, no doubt, content of 105.0 p.p.m. and, if made in the Proceedings of the Laboratory bon the careful work of Dr. Charles W. Peterson produce a sterile condition. . from a 15.0 percent solution with tap in obtaining these counts from the storage tanks. The germicidal results obtained w1th water, may have a pH of about 0.3 less TABLE 7 than the solution containing 255 pip.m. solutions of 30 p.p.m. of available chlor­ Bacteria comzts per square foot i11 storage tanks after 3 mi11utes exposure to chlorilze wlutions ine at pH 6 and 11 are included for The 15 percent chlorine solu~ions , Sample Left Right comparison. when manufactured, are made strong!}' No. Treatment side Average side Average A more severe test of the germicidal alkaline because they are more stable in 1 Unchlorinated areas 480 1,500 quality of chlorine solutions was made this condition. This stability renders 2 Unchlorinated areas 250 530 by determining their potency against them less active as germicides. Sucili so­ 3 Unchlorinated areas 530 750 4 Unchlorinated areas 2,600 1,800 spores of B. mbtilis. This organism and lutions are commonly used in the inclustcy 5 Unchlorinated areas 1,600 620 its spores, which -commonly occur in the for sterilization by diluting to the de­ 6 Unchlorinated areas 2,400 1,400 soil, is a frequent contaminant in all food sired available chlorine content. One 7 Unchlorinated areas 1,600 1,600 plants. When spores that were a month was employed as a basis of comparison 8 Unchlorinated areas 1,900 4,200 9 Unchlorinated areas 2,800 250 old were exposed to 255 p.p.m. of avail­ in this work. 10 Unchlorinated areas 390 860 able chlorine at a pH of 9.5 for 3 min­ Accordingly from the same 1~ percent 11 Unchlorinated areas 1,500 1,000 utes, an original count of 48,000,000 per stock solution a series of solutwns was 12 Unchlorinated areas 3,900 790 ml. was reduced to 30,000,000. In this prepared with tap water just as it wo~d be in the plant. The available Ghlonne 1,662 1,275 case the potency of the strong chlorine 13 Chlorinated 53.1 p.p.m. pH 6.35 0 50 solution had been reduced by the high contents of these solutions were 255, 106. 14 Chlorinated 106.0 p.p.m. pH 10.35 15 35 220 CHLORINE STERILIZATION JouRNAL OF MILK TEcHNOLOGY 221

plicate with one-tenth dilutions on stand­ purpose was to determine germicidal change materially through the tem­ germicidal results as a solution con­ ard media according to standard proce­ quality under the severest conditions. perature range from 50° to 90° F. taining 255 p.p.m. of chlorine at a pH dure. After 48 hours incubation at 37° Allowance must be made for this differ­ The actual change was less than 0.5 around 10. C., the counts were obtained as shown in ence if the results obtained under plant pH. BIBLIOGRAPHY table 7. conditions are compared with those in 5. Acid sodium phosphate is a satisfactory agent for adjusting the pH to the ( 1) Rideal, E. K. and Evans, U. R. The The same procedure was then followed any other part of this report. desired acid reaction. Effect of Alkalinity on the Use of Hypo­ with a chlorine solution of 255 p.p.m. Any recommendation for the most sat­ chlorites, f. Soc. Chem. Ind. 40, 64 R-66 and a pH of 10.60, and one of 53.1 isfactory concentration of chlorine for 6. Two minutes seems to be too short a R (1921). p.p.m. and a pH of 6.30. The counts sterilizing must be determined not . onl}l time to yield dependable sterility re­ (2) Scales, F. M. and Kemp, Muriel. The were obtained as shown in table 8. by the speed of action and potency of the sults under the conditions employed Fundamental Principles of Chlorine Ster­ The results of both these plant tests solution but also by its corrosive quality in this work even wit-h acid pH values. ilization and a New and Positive Germ­ 7. It is shown by laboratory and plant icide Proc. Internal. Assoc. Milk Dealers, indicate that when chlorine solutions are on various metals. (1938) pp. 3-24. tests that a solution containing 50 sprayed on the surface of equipment that Since a solution containing 50 p.p.m. ( 3) Scales, F. M. and Russell, Harriet E. has been cleaned and rinsed, a spray con­ of available chlorine at a pH of 6 is a p.p.m. of available chlorine at a pH Chemical Sterilization of Glass Lined taining 50 p.p.m. of available chlorine satisfactory sterilizing agent, any corro­ around 6 will produte as satisfactory Tanks, ibid. 1930. pp. 96-103. with a pH value of about 6 will produce sion that such a weak solution might as nearly a sterile surface in 3 minutes as produce may be very much reduced or a spray of 255 p.p.m. and a pH value of even entirely prevented by using it short­ The Irradiation of Milk discussion of other effects of irradiation, ly before the processing time. about 10. Within ·the past few years, the irradia­ including that on flavor, and lists 85 DISCUSSION references.-The Irradiation of Milk, CONCLUSIONS tion of milk has increased until now there by K. G. Weckel and H. C. Jackson, In determining germicidal power in 1. The results prove the greater germi. are approximately 130 licensed fluid milk Wisconsin Agr. Exp. Sta. Research Bul. the early part of this work, a period of cidal efficiency of chlorine solutions dairies in the United States and Canada 2 minutes frequently proved to be too when the pH is adjusted to around 6. irradiating their milk, and over half of 136, 1939. ]. H. SHRADER. short a time to produce sterility but one all evaporated milk produced is irradi­ of 5 minutes was generally satisfactory. 2. When the pH value of the solution is 8 or under, 90° F. appears to be a ated. The scientific data on which this For this reason the intermediate time, 3 New Law Book on Milk Control better t-emperature for steriling treat­ great development rests have been as­ minutes, was selected as most likely to ments than any lower one. sembled and correlated in an orderly and Producers and distributors of milk and show differences in this quality. In plant clear presentation in this new bulletin. dairy products who wish to avoid lia­ 3. Chlorine held at from 50" treatment the exposures are usually longer solutio~s The subjects dealt with begin with a bility and preyent cqnflicts with official to 90° F. showed no important loss than this so that the speed of germicidal discussion of the prevalence of rickets regulations will find much of interest and .in chlorine content in half an hour in action becomes a margin of safety. and the relation of vitamin D to adequate value in a new book by Dr. James A. the pH range from 6 to 11. In the different tests reported, the nutriti0n and health. There follows a . Tobey entitled "Public Health Law". inoculum was always far heavier than 4. The pH values 'ftf solutions containing discussion of the nature of light and ra­ This comprehensive work of more than would be likely to occur in practice. The 50 p.p.m. of available chlorine do not diation together with the physical basis 400 pages was published in June by The on which the irradiation process rests. Commonwealth Fund of 41 East 57th TABLE 8· After this comes a discussion of the bio­ Street, New York City. It is a revised Bactet·ia counts per square foot in stot·age tank.r aftet· 3 minutes exposure to chlorine solutio s. assay technic with full illustrations of and enlarged edition of an earlier book Sample Left Right the various steps and sections of bones by Dr. Tobey, first issued in 1926, and No. Treatment side Average side Average to show the "line test" in various de­ used as a t-extbook in all of the leading 1 Unchlorinated areas 710 110 grees of healing, indicated by the num­ university schools of public health. 2 Unchlorinated areas 700 590 ber of plus signs. Then the chemistry A feature of the book is a chapter on 3 Unchlorinated areas 800 100 of vitamin D, and the character of radi­ milk control. Also included are chap­ 4 Unchlorinated areas 830 430 ant energy from various sources. Several ters on foods, drugs, and cosmetics, and 5 Unchlorinated areas 170 570 6 Unchlorinated areas 450 120 illustrations are given of each type of on liability, while other sections are con­ 7 Unchlorinated areas 920 380 commercial equipment using respectively cerned with the powers, duties, and func­ 8 Unchlorinated areas 430 670 the carbon arc, the quartz mercury vapor tions of federal, state, and local health 9 Unchlorinated areas 210 540 lamp, and the high voltage discharge tube officials. 10 Unchlorinated areas 500 370 11 Unchlorinated areas 780 480 (commonly called the cold quartz tube). Dr. Tobey is also the author of a book 12 Unchlorinated areas 550 300 Factors which control the effectiveness entitled "Legal Aspects of Milk Con­ constancy of irradiation follow, to­ ~88 and trol," which was published by the Inter­ 588 ,gether with the control technic and equip­ national Association of Milk Dealers in Chlorinated 53.1 p.p.m. pH 6.30 0 50 13 ment. The bulletin concludes with a 1936. 14 Chlorinated 255.0 p.p.m. pH 10.60 0 50 fi JVUKL~J\L Ul'' !Vl.ILK l ECHNOLOGY 223

Examination of table 1 indicates a gen­ 32.7 percent (the average for the group), eral lack of uniformity in the percentages and the increases of only 22 ( 3.3%) of of average increase in count on T-G-E-M the samples in this whole group lay be­ A Comparison of Plate Counts of Raw Milk on the Agar over Standard Nutrient Agar. The tween 30 percent and 35 percent. percentages of average increase in count The numbers and percentages of cases Old Standard Nutrient Agar and on the New range from 9.3 percent on 90 samples in which the counts were increased, de­ in the range 110,000 to 200,000 per cc., creased, or remained unchanged by plat­ Standard Tryptone-Giucose-Extract-Milk Agar to 42.6 percent on 125 samples in the ing on T-G-E-M Agar, and the ranges C. A. Abele and S. R. Damon range of 0 to 5,000 per cubic centimeter. in the percentages of change from the Alabama State Department. of Health, Montgomery, Ala. Considered cumulatively, however, these counts on Standard Nutrient Agar, are percentages of average increase are some­ given in table 3. what more uniform, as indicated by ,table In anticipa:tion of the mandatory use of presents an analysis of the comparative SEARCH FOR DEFINITE RATIO 2. In order to determine whether there the tryptone-glucose-extract-milk agar, plate counts of 1000 raw milk samples TABLE 2 (hereinafter designated as T-G-E-M) pre­ examined between March 8 and July 20, is any definite ratio between the count Cumulative Percentages of. Average Plate scribed by the American Public Health 1939. The medium used was Bacto on Standard Nutrient Agar and that on Comll htn·eases T-G-E-M Agar, within certain ranges of Association Committee on Standard Meth­ Tryptone-Glucose-Extract-Milk Agar wit~ Percentage count magnitude, the groups of counts ods for the Examination of Milk and 1.0 percent Bacto skimmilk added since Range on Standard Average Increase Nutrient Agar on T-G-E-M Agar within . each of the ranges used through­ Dairy Products ( 1) as the standard agar only 1 : 100 and 1: 1000 dilutions were for milk plate counts after July 1, 1939, 0·5,000 42.6 out thts study were divided: first, into plated. The milk samples were those the Montgomery laboratory of the Ala­ 0-10,000 30.9 groups of twenty as they were recorded; routinely delivered to the laboratory by 0-25,000 33 .6 bama State Department of Health has 0-50,000 32 .7 second, in~o thirds, by grouping the al­ plated samples of raw milk on the new the Montgomery dairy inspector, and 0-100,000 30.9 ternate thud samples; and finally, into medium as well as upon Standard Nutri­ such as were shipped from neighbo.dng 0-200,000 22.6 halves, by grouping odd and ·evenly num­ ent Agar in order to note the effect upon communities in the normal course of milk 0-500,000 23.9 bered samples separately. The results of 0-1,000,000 25 .7 ~hese determinations of average increases counts. Since average plate counts con­ control. Slightly less than half the sa1D­ 0·1,000,000 plus 21.2 stitute one of the principal factors in the ples considered in this study were of milk m count are .presented in table 4. grading of milk supplies throughout the for pasteurization, the remainder being The .figures in table 2 must be accepted A glance at a work sheet of individual country, the effect of the use of the new merely as averages. For instance, the percentages of increase or decrease in street and special samples of retail raw increase of not a single one of the 125 agar upon milk grades is a question of milk. ·' · count on T-G-E-M Agar of a series of deep interest. counts in the range 0-5 ,000 per cc. on any twenty samples comparatively ·exam­ The report of Abele ( 2), the prepub­ COMPARATIVE COUNTS ON THE Standard Nutrient Agar was exactly 42.6 ined would no doubt lead an observer lication data of which were available, ,TWO AGARS percent ; the nearest percentages to this to q':estion the likelihood of group uni­ dealt primarily with the effect of the The gross results of the comparative average were 41.7 percent and 44.2 per­ formtty of percentage increase within cer­ use of the T-G-E-M Agar upon pasteur­ counts on the old a"nd the new agars are cent. Likewise, the increase of not one tain rjlnge limits ; but the data in table ized milk counts. The present report presented in table 1. of the 655 counts under 50,000 per cc. 4 should convince him of the improba­ on Standard Nutri-ent Agar was exactly bility of such uniformity. With rare ex-

TABLE 1 Comparative Plate Counts of 1000 Raw Milk Samples on TABLE 3 Statzdard Nutrient atzd T-G-E-M Agars Perce11tages of bm·ease.r Ol' Decreases in Counts 011 T-G-E-M Agar (lnn·ease ot· deet·ea.re based upon Standard Nutrient Agar count) Range of Counts Arith. Average Arith. Average Percentage on Standard No. of of Counts on of Counts on Aver. Increase Range of Counts on Standard Nutrient Agar Counts Standard Nutrient Agar T-G-E-M Agar of Count Increased Unchanged Decreased Range of Change Nutrient Agar No % No % No % Decrease Increase 0-5,000 125 3,518 5,006 42.6 144 7,552 9,544 26.4 0·5,000 97 77.6 4 3.2 24 19.2 -27.3% to+ 255.5% 5,100-10,000 l,100-10,000 11 ,000-25,000 218 16,591 22,346 34.8 97 67.4 6 4.2 41 28.4 -55.2% to+ 938.4% \1,000-25,000 149 68.4 26,000-50,000 168 35,637 47,030 92.0 21 9.6 48 22.0 -40.0% to+1,718.1% 136 74,191 95,574 28.8 26,000-50,000 121 72.1 11 6.5 36 21.4 -37.0% to+ 778.7% 51,000-100,000 l1,000-100,000 110,000-200,000 90 144,778 158,222 9.3 99 72.8 5 3.7 32 23.5 -32.8% to+ 345.3% 2,.6 110,000-200,000 20 22.2 210,000-500,000 72 349,444 439,000 50 55.5 20 22.2 -27.3% to+ 105.9% 24 733,333 965,000 31.6 210,000-500,000 57 79.1 2 2.8 13 18.1 -31.2% to+ 480.0% 510,000-1,000,000 15.7 )10,000-1,000,000 Over 1,000,000 23 2,695,652 3,118,261 17 71.8 1 3.2 6 25.0 -26.8% to+ 216.7% Over 1,000,000 17 73.8 0 o.o 6 26.2 -30.2% to+ 131.2% 21.2 Totals 1,000 139,011 168,506 :

t'O'D"<:fOOtn 1,000 comparative : counts may difFer milk over 50,000 per cc. on Standard growth of some organisms the multipli­ r....:""'cx)«)('(\ NV"\OON'q< somewhat in its percentages of average Nutrient Agar were less than 50,000 per cation of which is inhibited on Standard increases from every other group of 1,000 cc. on T-G-E-M Agar. One count of Nutrient Agar, the plate counts of low­ ('('lCOr-t-t-G\ ..Co.:::FN 6 t'i 00 00 -q: 00 counts, the differences may lie within prepasteurized milk over 200,000 per cc. bacterial-content mifk are not (or only r()....-4('1('("'\('("\ comparatively narrow ranges. Therefore, on Standard Nutrient Agar was under rarely) increased to an extent to jeopard­ t---N'<:f'O...... C\Ot­ the examination ,...of the 1,000 c;ounts ize tQ.e grade. In the comparatively rare v-\\!)v-\~.....; rnC"i this limit on T-G-E-M Agar. These r()N NN N under scrutiny, with respect to possible lower counts would have affected the instances in which low counts on Stand­ ard Agar are increased on T-G-E-M Agar -oo \O...... t\,CIIf"\OC\lf"\ changes in grade, may be of interest. grade favorably. C:N N~r...:«)v-\0.__..; 1/\....-41"""'1\0r-4...-41'""'( Of the 529 counts of retail milk, 378 sufficiently to change the grade, it must "' were 50,000 or less per cc. on Standard CONCLUSIONS be recognized that these organisms were Nutrient Aaar; and of the 471 counts of The plate count of raw milk, using nevertheless present in the milk, even bulk milk bfor pasteurization, 384 were T-G-E-M Agar, as compared with the though not developed by the Standard 200,000 or less per cubic centimeter. (These limits are used because they are TABLE 5 those fixed by the U. S. Public Health Grade Altered Because of Higher, or Lowet' Counts on T-G-E-M Agar Service Milk Ordinance for the upper Range on Retail Milk Milk for Pasteurization grades of raw milk a~d of milk for pas· _tandard Nutrient on T-G-E-M Agar on T-G-E-M Agar l/"\"<:110000\00N'<::t'N'"'IN'-::r....-4\0("{"\G\t-NN I og" Agar ...-4.....-!Nr-4.....-t teurization.) A pprox1mately 10 perttn~ ...... Under Over Under Over of all (655) counts of 50,000 or less per 50,000 50,000 200,000 200,000 cc. on Standard Nutrient Ag~r were per cc per cc per cc per ct over 50 000 per cc. on T-G-E-&fl Agar. 0·5000 100 0 25 0 But nea~ly 60 percent of these i~cr efor 5,100-10,000 95 1 48 0 occurred in sampl·es of bulk milk f. 11,000·25,000 121 4 93 0 26,000-50,000 62 23 83 0 uPI pasteurization, and the grade was 51,000-100,000 4 77 2 fected. 'ch l10,000·200,000 58 8 The numbers of instances in wh1 __..._._ 'l!0,000·500,000 l J. LJ"l.J..C \....VUl..,_. .lo':> V1""4 J."'~W L'l.lJ/\.K LL.I

Nutrient Agar plate, and that the grade The results of this study, if they may awarded on the Standard Nutrient Agar be applied to raw milk supplies of ap­ count was, to that extent, misleading. proximately similar quality, do not indi­ It appears that average plate count cate a need for change in the average Testing of Bottle-Washing Solutions limits now fixed in milk ordinances and plate count limits now fixed in milk con­ * regulations need not be raised to avoid trol legislation. C. M. Moore anticipated chaos in the grades of milk The Diversey Co t·poration, Chicago, Ill. supplies resulting from the higher counts ACKNOWLEDGEMENTS obtained by the use of the new Standard The w.riters are indebted to Cooper T-G-E-M Agar. Brougher, Assistant Director, of he In the machine washing of returned placed upon the treatment given the bot­ dirty milk bottles, two results are ex­ SUMMARY Bureau of Laboratories of the Alabama tles as they pass through the machine be­ pected from the cleaning solution. First, fore it can be said with assurance that One thousand samples of retail and State Department of Health for assist­ it must be capable of removing, elimi­ "these bottles are sterile and can be safe­ prepasteurized raw milk were plated in ance in the preparation of this report, nating or otherwise destroying the visi­ ly used as containers for the finest milk." duplicate on Standard Nutrient and Tryp­ and to E. A. Van Eck, Junior Bacteriolo­ ble dirt on the bottles; second, it must Of the various factors to consider in tone-Glucose-Extract-Milk Agars. gist in the Montgomery laboratory, who kill or be of such a nature as to be able appraising the sterilizing treatment given The percentages of average deviation made all the counts. to destroy the invisible dirt-bacteria, the bottles in the washing machine, three of the T-G-E-M Agar counts from those REFERENCES mold, and yeast. "Dirt" has been aptly are of outstanding importance. These are: plated on Standard Nutrient Agar, in the defined by the early Greek philosophers various ranges of count magnitude, were 1. Abele, C. A. Comparative Tests of Aw 1. The temperature of the solution. Media for Standard Milk Work. America~ as "matter jn the wrong place." Dirt extremely non-uniform. Public Health Association Yearbook, 1938- present on returned milk bottles will vary 2. The time of contact between the solution and the bottle. It appears to be impossible to approxi­ 39, p. 79. from the product itself which has dried mate the percentage of deviation in 2. Abele, C. A. Results of Bacterial Plate on and adhered to the glass surface, to 3. The strength of the solution. Counts of Milk on Three Media and at :Fwo counts, or to translate the count on one remnants of materials for which the bot­ The first two factors are easily mea­ medium into terms of that on the other. Temperatures of Incubation. Am. J. Pubif, Health, in pre5s. tle has been used as a container but for sured. A thermometer can be placed in The number of instances in which the 3. Kelly, Ernest. Report of Collaborator on which it was never intended. th_e solution tank and the •temperature ob­ higher count on T-G-E-M Agar would Cooperative Work with Proposed Changes The more insidious forms of dirt, tamed at a glance. Most bottle-washing have altered the grade of a milk supply in Medium and Temperature of incubation, which cannot be seen with the naked ·eye machines are already equipped with a retained by the Standard Nutrient Agar 29th Anual Proc. Lab. Sect. Intern . J.JJn, thermometer for this purpose. The time Milk Dealers, 1936'pp. 50-75. -bacteria, mold, and yeast-are always count was very small-7.4 percent in the present in dirty milk bottles, and find, in of contact can either be obtained from case of retail raw milk, and 2.6 percent 4. Bradfield, Alec. Bacterial Content of IM.ilk, as Affected by the Use of Different Plattng even the thin film of organic matter left, the ~anu.facturer of the bottle-washing in the case of bulk milk for pasteuriza­ Methods. Vermont Agr. Exper. Sta. Bull. ideal breeding grounds. The three con­ ~achme or checked by actual observa­ tion. 417, 1937. ditions necessary for growth-food, tem­ tiOn of the machine in operation. The perature, and moisture-are almost al­ third factor-the strength of the solu­ ways present in such bottles. tion-.has proved somewhat of a stum­ As the washed bottles leave the ma­ bling block in the past. Just what actu­ A Single-Dip Stain for the Direct Examination of Milk * chine and are set up on the inspection a!ly comprises the strength of the solu­ J. Broadhurst and C. Paley platform, they are usually carefully in­ tiOn and how can this best be measured? spected to make sure that not even a The cleaning solution is expected both This stain is employed for making di- bacteria and all other cells and foreign trace of visible dirt is present. The abil­ to clean and sterilize the bottles. Since rect microscopic counts of milk, accord- bodies, such as precipitated dye, etc. _Eye ity of the solution to clean the bottles in the cleaning strength or ability of the ing to the Breed method. It combines strain is eliminated because the orgamsms so far as visible dirt is concerned can be solution to remove visible dirt is checked fat extraction, fixing and staining. do not have to be searched for and are accurately measured at this point. But and measured by examination of the bot­ The stain contains ethyl alcohol, a not hidden by darkly stained, congealed how about the ability of the solution to tles as they come from the machine, it very small quantity of concentrated sui- serum solids on the smear. The serum sterilize the bottles? Can it be measured seems obvious that the test which pro­ phuric acid, tetrachlorethane, methyJene solids appear very faintly pink while the by examining the bottles as they leave vides the best index of the sterilizing blue dye, and an alcoholic solution of organisms and other cells are blue. No the machine? No amount of looking at abili•ty of the solution would be the test basic red fuchsin. decolorizing of a heavily stained smear a washed bottle will tell whether or not to select in appraising the strength of the The advantages of this stain are that is necessary. it is free from bacteria, mold and yeast. solution. Therefore, in considering the there is a differential background permit- The preparation of the stain is simple. Obviously, therefore, dependence must be various tests that are used or that have ting the easy differentiation between the The technique employed is basically the been proposed for bottle-washing solu­ same as that employed when using the -• Presented at Twenty-seventh Annual Meetin~ of tions, it would apper.r fundamentally the International Association of Milk Sanitanaos, * Am. Vet. Med. Assoc., N .S. 47, 525-526 Newman-Lampert stain. C. p, C1eveland, Ohio, October 19·21, 1938. sound to keep before us the question, (1939). 228 BOTTLE WASHING SOLUTIONS JOURNAL OF MiLK TECHNOLOGY 229

"Does this particular test of the solution was ever present in the solution, and THE TOTAL ALKALI OR TOTAL FREE CAUSTIC TEST provide an index of the ability of the so­ further, we knew the sterilizing strength ALKALINITY TEST The test for the total or free caustic lution •to destroy bacteria, mold and of the particular material-then, and only This test is made by withdrawing a content of a solution is made similarly yeast?" then would the hydrometer provide a sample of the bottle-washing solution, to the . total alkalinity test. However, it At the present time there are perhaps satisfactory means of testing the solution. usually 10 cc. and sodium carbonate. When titrated to the ate, forming insoluble barium salts. It 2. The conductivity test. down somewhat in the solution and be phenolphthalein end point, the standard does not react with any free caustic pres­ Let us consider each of these •tests on partially depleted in sterilizing strength, acid will neutralize all the caustic soda, e?t in the solution. The sample is then the basis of what it shows, or for that and yet the weight of the solution would one-third of the trisodium phosphate, and titrated to the phenolphthalein end point, matter fails to show, and particularly not necessarily be affected. The hydro­ one-half of the sodium carbonate. With and since only caustic soda is present, the whether or not it provides an accurate meter could not show this change. Be­ other indicators, some of which have amount of a:eid required to neutralize the index of the sterilizing strength of the cause the hydrometer cannot distinguislb been 'Propo~ed, different results would sample is a direct index of the amount solution. one material from another, but depends be obtained, depending upon the pH of caustic soda present. in the solution. THE HYDROMETER TEST entirely upon the weight of the solution range of the indicator selected. The other method for determining to­ As can be readily appreciated from the tal or free causticity is known as the In the earlier days of bottle washing it is obvious that such a means of test: method by which the test is made, the double titration procedure. Here the operations the hydrometer was used al­ ing bottle-washing solutions is at best total alkalinity of the solution is nothing sample is first titrated with standard acid most exclusively for testing bottle-wash­ very poor indeed. more nor less than the acid neutralizing to the phenolphthalein end point. The ing solutions. The hydrometer measures Table 1, taken from Educational Bulle­ value of the solution. It is true that amount of acid required is carefully the weight of a solution without any re­ tin No. 1 of the American Bottlers of these results may sometimes be expressed noted and the titration then continued gard for the particular material or ma­ Carbonated •Beverages,. based on work con. as caustic equivalent, but this of itself with methyl orange as the indicator. terials present in the solution. A care­ ducted by Dr. Max ·Levine and Dr. .H. J. does not necessarily mean that the solu­ Since the :first titration results from the fully calibrated hydrometer does, there­ Buchanan, shows the tremendous varia­ tion contains any caustic. A solution of, caustic present .. in the solution and a defi­ fore, serve with reasonable accuracy as an tion under 'Practical operating cond~ t.i ons say, 3 percent caustic equivalent simply nite fractional part of each of the other index of the weight of a particular solu­ that may result between the hydrometet means that the solution has the same alkalies, and since c the second titration tion, without, however, any considemtion test and the actual 'austic content of the acid neutralizing strength a specified accounts for the same definite fractional as . to what comprises the additional solution. Only id'· the case of sample to indicator as a solution containing 3 per­ part .of each of these other alkalies, then weight of the solution over plain water. No. 2 was the hydrometer reading reason­ cent caustic soda. The term "caustic merely subtracting the second reading Now, if bottle-washing solutions were ably close to the actual causticity of the rquivalent" is very confusing, and it is from the first gives us the amount of acid prepared from one material and that solution, and this, of course, is onlY. a unfortunate that it is used in many of our required to neutralize only the caustic. material alone, and only tha•t material coincidence. health department regulations dealing This in turn is quickly factored to free with the strength of bottle washing so­ caustic. TABLE 1 lutions. If it were true that the ability CAUSTIC AND ALKALI NOT THE SAME of a solution to neutralize an acid was The test for total or free causticity dif­ Bawmf cmd Causticity of Bottle JJV ashing Solutions an index of its sterilizing strength, then fers from the total alkali or alkalinity Sample Baume Percent caustic Actual percent Percentast the test for total alkalinity would meet test in that the former measures the number reading by hydrometer as caustic error our requirements for an accurate test of amount of only one particular alkali­ 1 2.81 1.81 2.27 20.2 the bottle-washing solutions. There is, caustic soda that is present in the solu­ 2 3.60 2.24 2.19 2.28 bowever, no direct relationship between tion-whereas the latter measures all the 3 4.08 2.56 2.16 18.5 4 4.43 2.78 2.15 29.3 the ability .of a solution to neutralize alkalies present. Unfortunately, many 5 4.74 2.98 2.16 37.9 acids and its ability to kill bacteria, mold people use the word "causticity" and 6 5.14 3.24 2.18 48.7 or yeast. Hence, the total alkali or test "alkalinity" interchangeably as meaning 7 5.61 3.54 2.12 66.9 for caustic equivalent cannot be consid­ the same thing. This is the cause of 2.02 78.2 8 5.71 3.60 ered as a satisfactory test for bottle wash­ 9 5.83 3.68 1.92 91.6 much of the confusion that exists in test­ Data Courtesy DR. MAX LEVINE and A. B. C. B. Ing solutions. ing of bottle washing solutions. "Alka- JoURNAL OF MILK TECHNOLOGY 231 li" is the family name of those materials soda, however, is a very harsh and corro­ which are neither acid nor neutral. Ma­ sive material. If it were used for wash­ bonate, or soda ash; and straight soda containing 4 percent total atkalinity, pre­ terials suhing of drink­ a germicidal agent. Caustic soda, how­ pounds per 100 gallons Jlre also shown of these last two tables that the germi­ ing a solution of baking soda, yet the ever, does destroy bacteria, mold, and at the bottom. The test organism se­ cidal efficiency of the various alkalies consumption of even a small amount of yeast, under the proper conditions of, lected for these tests was a strain of with this particular organism is closely a caustic soda solution would lead to concentration, temperature, and time 0 ~ Staphylococctts attreus· of standard phenol related to the free caustic content of the disastrous results. Yet both are alkalies. contact. These conditions have been. resistance. The test was made at a tem­ solution, with one or two minor excep­ To further illustrate the difference be­ pretty well established by numerous lab­ perature of 98.6° F., this temperature tions. It is particularly to be noted that tween total dkalinity and total or free oratory and practical plant tests. A test being used s6 that the destruction of the where the causticity reached a definite causticity, let us assume that we have of the solution for total causticity does organism was due entirely to the solution concentration of slightly less than 1 per­ some sodium carbonate and some caustic provide a reasonably accurate index of and not to outside factors, such as tem­ c~~ t , al_l th~ solutions of greater caus­ soda. Caustic soda is also known com­ the sterilizing strength of the solution, perature. It is obvious from the results tiCity dtd ktll the test organism in less mercially as lye----chemically as sodium while the test for total alkalinity is of shown in this table that there is no con­ than 1 minute. This statement could not hydroxide and sodium hydrate. Now both little practical value in this respect. nection whatsoever between the Baume be made with solutions of equal alkalinity sodium carbonate and caustic soda are Some recent bacteriological tests made or specific gravity of the solution and or equal specific gravity. alkalies, yet everyone knows there is a by our Research Laboratories in conjunc­ its germicidal efficiency. Within the last few years, several prod­ tremendous difference between them. So­ tion with the Columbus Laboratories of Table 3 shows the results of tests made ucts have been offered for machine-wash­ dium carbonate is commonly used for Chicago illustrate tli~· value of the three under identical conditions, except that ing of bottles, with the recommendation washing clothes and various other house­ methods of testing bottle-washing solu· the amount of each product used was that they be used at a concentration which such as to give equal total alkalinity with hold cleaning jobs. It is a common con­ tions which we have discussed. In tl!\ese ~ives approxin:ately y2 percent caustic­ stituent of many dairy cleaners, and as tests we used three products for making the three products. The solutions were tty. It ts clatmed that these materials such can be safely used in hand washing up the solutions,..,..commercial caustic equivalent in acid neutralizing value, and contain substances other than caustic operations. It is indeed generally 11.20 17.45 23.40 5.80 11.80 17.80 23 .60 5.96 11.9 17 .45 23.8 100 Gallons KEY: + = Bacterial growth; - = No bacterial growth 4.25 8.50 17.00 25.50 6.12 12.26 24.50 36.80 22.55 45.1 67.6 90.2 Organism: Staphylococcus aureus strain KEY: + == Bacteri.al growth; - = No bacterial growth of standard phenol resistance Orgamsm: StaphylococcuJ artt'eus strain of Temperature: 98.6° F. standard phenol resistance Temperature: 98.6° F. TABLE 4 as "A," "B," and "C." The chine. However, when the solution is Germicidal Efficienc_"' of Alkaline Materials was made with solutions of maintained· at the same total alkalinity by Test No. 3-Solutions of Equal Causticity and the solutions each daily test for alkali only, then the caus­ 50% Caust~c Soda ticity of the solution will gradually de­ Product Caustic Soda 50% Soda & !i 1 percent, 1.8 percent, and . 3 causticity. The temperature m crease and the solution in turn become % Causticity 0. ~ 1.0 2.0 3.0 0.5 1.0 2 0 Time 1 Min. + + + + . test was 130° F. and the time of less efficient in its sterilizing action. 3 Min. + + + 1 3 and 10 minutes. These con- Under these conditions it would be pos­ 5 Min. + + . . dos~ly approximate av-erage bot- sible for the solution to lose practically 10 Min. + + Jtuons hing operations. It will be no­ all of its sterilizing strength, and yet the % Alkalinity 0.51 1.02 2.05 3.06 .70 1.39 Pounds Per 2.78 tle·"'~hat the destruction of the org~n­ test for total alkalinity would fail -to re­ 100 Gallons 4.25 8.50 17.0 25.50 8.50 17.0 34.00 with each of the three commerctal veal this serious -condition. Daily test­ KEY: + = Bacterial growth; - =No bacterial growth ducts is rather closely relate~ to the ing of the solutions for its total causticity Organism: Staphylococcus aut·erts strain of f: caustic content of the solutiOns. . makes it possible to maintain the solu­ standard phenol resistance tion at the proper strength to insure de­ Temperature: 98.6° F. · The bacteriological results shown tn struction of bacteria, mold, and yeast. 1 t four tables are all made from je has elutions. Other investigators have The effect of temperature, time of con­ sterilizing action over caustic soda seems 5 Table 5 shows the results of (res that the germicidal action of caus­ tact and free causticity in the solution is to be beside the point. The main fact is iological tests with organisms ~"'da is not materially affected by the shown in Figure 1. These results are that the sterilizing strength of the solu­ somewhat more difficult to Clestroy 50 tion cannot be determined by any test UC ce of even excessive quantities of Staphylococcus attretts. This work presen·c matter so long as there is suffi- other than bacteriological examination of otgan 1 . h l . conducted by an independent • t free caustic present m t e so utwn. the washed bottles. This should be 1 laboratory of recognized standi~g actual 'use in the bottle-washing \ enough for any conscientious health ~ \g while the particular organisms ' the solution will be conta_m­ offi-cial or dairy plant to condemn the use 142~hlne, closely related to brewing qpe:rattoni . ~•ed with dirt from the bottles, whtch of products with mysterious and unrec­ is likely that the same orgamsm 10.. f h · · ognized sterilizing action when used at will tend to use up some o t e caust~ctty ganisms of similar resistance, ar~ of the solution, as well as react -chemtcal- low caustic strengths for washing milk be present in returned dirty milk 1 with some _of the other _alkalies. Some bottles. Germicidal action which cannot as well as the bottles used for '£ the dirt wdl form alkalies of no ster­ be measured by a simple test is little that are bottled, handled, and value with the free caustic, and, better than guesswork, and has no place ~ iting --- by many dairies. Three types of course, the well knowfl: reaction wit_h ~ ...... _ in -bottle washing operations, when it is ~! isms as listed in .,the· table were a rbon dioxide in the atr and caustic -- ... - - ~ - · -·~ ·-r_,_ - ·- - ·-·-·- so easy to actually determine the steril­ this investigation. ' The solutions !O

c_austic present in the solution, with the other materials present in ,tO characteristic of the solution, practically any of the many forms in time of conta-ct of the solution on the which will influence the e is quite important in preventing which it will be encountered on dirty organism? and with the temperature of the solution, and yet contni b t to the moving parts of the rna- bottles. Such products are decidedly ~he s~lutJon. The type of organism used to its sterilizing effiGieney. u Ttus that come in contact with the so­ superi or to -caustic soda in softening m this work was spedfically selected be­ therefore~ would seemingly fail t Further, a solution of sufficient water, and this characteristic is of par­ cause the difficulty with which it is de­ the requuements of a suitabl 0 tQ sterilize the bottles has a ticular advantage in hard water localities stroyed makes it suitable for research bottle-washing solutions· in the t~t influence on the metal parts in producing bottles that are free from work of this type. "d . d at 1t no t ~:rovi e an m ex of the ability the machine with which the solution film or scale, at the same time keeping the machine at the peak of operating ef­ THE TEST FOR PH solution to destroy bacteria ld 5 in contact.· From time to time it has been pro­ yeast. ' mo • It is not to be assumed that proper ficiency. Solutions prepared from straight posed that the pH test be used for bottle­ Table 6 summarizes the v.ar· of the solution used for washing caustic soda are difficult to rinse, while . • IOUS those from specially designed bottle­ washing solutions. However the fact that o d s. o f testmg bottle-washing will by any means solve all the washing compounds rinse much faster and t?is test is rather difficult to make, par­ whiCh have been dis-cussed f connected with the efficient and 0 1 ma-chine washing of bottles. more completely. There are many fact­ t~cularly under plant operating condi­ only the test for total , · ce hons, has substantially limited its use to ly related to the sterilizing cmaelnrv ~l.': proper test of the bottl~- washi?g ~o­ ors to consider in selecting a cleaner for theoretical considerations. In addition the solution, and at the same tim is important to the m1lk samtanan bottle-washing operations which are be­ yond the scope of this paper. The prop­ the the pH be easily made. e the dairy in that it provides one of relati~n~hip b~t:veen valu~ er use of bottle-washing compounds in­ and germlCldal ability of the solution safeguards on the quality of market CAUSTIC TEST MEETS REQUIIU!M \W"hile caustic soda alone provides sures bottles that are free from bacteria, seems. to vary co~siderably with different sterilizing action in the mold, and yeast, and bottles that have a o~gamsms and different materials. Like­ If we accept the premise that the wise, the pH value of the solution does f?r the strength of bottle-washing solution, it leaves much to brilliant lustre and sparkle-that reflect not necessarily take into consideration the ~1ons must provide a reasonaMy 11e desired in other characteristics. Prod- the quality of the milk. The glass bottle reserve strength of the solution. For mde~ of the sterilizing strength of specially designed for bottle-wash­ has long been recognized by the publi-c example: A solution may be of the proper solutiOns, then I believe we will Qperations, which -contain caustic soda as a symbol of purity. A product well pH to destroy bacteria at the time the that only _the test for total tlaUJ'tiGity base, will generally give better re­ displayed is ha~f sold. Properly washed in the bottle-washing machine. Such glass bottles make it possible to display test is made, and yet be unsuited for this . our requueme~t~. . Moreover, the milk in an attractive manner. work a half ·hour later because of the for ~otal -causticitY, ) S. easily made are capable of attacking dirt in sudden drop in the pH value. sufliCJent accuracy by· even an plant operator, so no .diffit;ulties THE CONDUCTIVITY TEST countered on that score. Tesli.ing Chlorine Rinse Reduces Bacteria at Low Cost . A recently proposed method for test­ lutio_n daily for. tota! caustl ci ~ mg bottle-washing solutions is apparent­ possible to readily *termine: the J. W. Yates ly based _on the conductivity of the solu­ of_ cleaner re9uired for upke~;p Pennsylvania Salt Marmfactttring Company, Philadelphia, Pa. tion, which is the ability of the solution tam the solutiOn at a definite and to -carry an electric current. While con­ sterilizing value. While the We wonder sometimes if milk pro­ inorganic washing compound. Then the ductivity tests may serve as a useful index son for testing bottle-washing appreciate the good work a proper utensils are to be rinsed further with of the strength of the solution when one for total or free causticity comes bactericide will do, and how water hot enough to dry ~hem when they it costs to use for bacterial control are inverted to drain. Just before use, materi~l, and .t~at material alone is pres­ ~he fa-ct that this test provides the ent, this conditiOn cannot be met in bot­ mdex of the sterilizing stl!ength, farm milk utensils. It does not take they should be put in a chlorine bacteria­ pennies to put utensils in ex-cellent tl_e-washi~g operations, as has been pre­ ~re two other advantages;, of nhe killing rinse to cut down the large per­ ·. u nornnr condition for handling pure milk. VIOusly discussed. There will always be Is a reasonably accurate indicator centage of bacteria which they may have For a herd of thirty cows, there is collected. They are then in an excellent ddl 3 to 4% pounds of chlorine pow- condition to handle the milk. TABLE 6 r a year at a cost of about $3.00 to This practice of bacteria control is very Summary of Methods for Testing Bottle Washing Solmiotts Certainly that is economy in view inexpensive. The cost in some instances the excellent results you get. There runs as low as a cent a day. The re­ Is test readily Relation to very little work to the operation which Method of Testing Measures made? Sterilization wards of good quality milk and low bac­ Hydrometer Weight of Solution Yes No ~les ~ producer to take advantage of teria count are well worth the small ex­ Total alkali Acid neutralizing power Yes No t111s effictency and economy in chlorine tra labor and cost involved in this pro­ Conductivity Ability to carry electric ? No wder. gram. The practice is general at this time current pH Degree of alkalinity After the utensils have been used, they on hundreds of thousands of farms, and Total or Free uld be rinsed free of milk solids and is approved by milk plants and health Causticity Amount of free caustic Yes n scrubbed with hot water and a good officers. JOURNAL OF MILK TECHNOLOGY 237

best by means of the routine control tests, Reduction time to white was determined with patrons' milk, tank car shipments of by continuing the incubation time to the Application of Resazurin Test in Determining raw milk, and batches of raw cream. point of complete color reduction. The results, accumulated to show the Quality of Raw Milk and Cream * METHODS comparisons of the reduction times of Ten milliliter quantities of the product M. A. Collins, Director of Quality Control, United Farmers Co -op. Creamery Assoc., resazurin to pink or white and of methy­ to be tested were placed in sterile test lene blue to white as well as to show the Boston, Mass. tubes. The tubes were then tempered to relationships of resazurin color changes L. M. White, Laboratory Supervisor, U. F. C. C. A., Morrisville, Vt. 98° F. in a large, temperature-controlled, to microscopic or plate counts and acid water-bath for 5 minutes. One milliliter W. H. Chilson, Laboratory Supervisor, U. F. C. C. A., Boston, Mass. increases, are presented in Graph 1 and of the fresh 0.005 percent resazurin dye in Tables 1 to 8, respectively. H. G. Turner, Jr., Field Supervisor, U. F. C. C. A., Morrisville, Vt. was then added by means of a 10 mi. J. R. Rice, Laboratory, U. F. C. C. A ., Morrisville, Vt. pipette and the sample mb~ ed by invert­ COMPARISON OF SOLUTIONS ing. The resazurin solution was made up The results secured when the reduc­ INTRODUCTION milk supplies and is very sensitive in se­ weekly and stored in brown bottles. Af­ tion time of 1 ml. of 0.005 percent res­ The results discussed in this paper lecting poor quality milk. References ter the addition of the resazurin, the azurin was compared with the reduction wer·e secured by the Quality Control De­ have been made continually to the high samples were incubated, either in the time of 1/10 mi. of 0.05 percent res­ partment of the United Farmers' Co­ sensitivity of the dye to light and to ab. large, temperature-controlled, covered, azurin are presented in Graph 1. Dupli­ operative Creamery Association in its normal milks. Several writers, notably water-baths or in the 3 7 o C. incubators. cate samples of patrons' milk were used. Morrisville, Vermont, and Boston, Mass., Barrett, Rutan, and Keenan, have re­ The samples. were prepared and read in The number of comparisons is shown on Laboratories. ferred to the time-and money-~aving medium light but away from direct or the graph. The data were compiled from the daily values of the test. A very high percent­ reflected sunlight. The first column represents the 4 hour routine tests which were made in deter­ age of agreement with other bacteriolo­ Observations for color changes were reduction time of 0.005 percent dye to mining the advisability of changing from gical tests in grading raw milk supplies made at 15 minute intervals. If reduc­ pink with 4 samples. In the duplicate the routine methylene blue reduction test has been mentioned in private discussion tion appeared to be at the pink ertd samples in which were used 0.05 percent to a routine resazurin reduction test for by Fay (2) of the H . P. Hood Company point, and the pink color had developed resazurin, 2 samples became pink in 4 the control of niw milk and cream sup­ of Boston. Moldavan uses the color· de­ slightly irregularly from top to bottom, hours, one ·in 3.5 hours and one in 3 plies. All tests were carefully contr~l!ed veloped at the end of one hour as a the tube was inverted once to bring the hours. Similarly are compared the re­ and supervised with a view to comptlmg basis for grading th~ patrons' shipmena. entire contents to a uniform color. Pro­ sults of the groups which were reduced the results for analyses, in the hope that Barrett, Rutan, an'd Keenan smear the nounced pink color, intermediate between in other time durations. Of the 50 com­ the results might be applied generally samples, which have changed color in one the purple pink and the vivid pink, was parisons made'" 33 or 66.66 percent and compared with those of other similar hour, to determine the cause of the: poor considered the end point of reduction. agreed completely and of the 17 which tests. quality. HISTORICAL EXPERIMENTAL.... The strength of the resazurin dye so­ It was thought early in the resazurin Compd.risoa at' Redactioa, Time to A.nk Uslng studies that the use of 0.05 percent res­ fcc. of o.oo5-l' & J1o cc. of o.o5% Resazuri.n lution (0.05 percent) was .recommended B~OXEN COLVMN-O.OOS" SOI..IO COLUJ1H-0.0S .ll' by Ramsdell, Johnson, and Evans (6) in azurin solution as recommended by Rams· 1935 and was used also by Barrett, dell ( 5) was not sufficiently ac:;curate Rutan, and Keenan ( 1) of the Whiting when speed is required, t-herefore the Milk Company, Boston, and reported in modification suggested by Moldavaru (4) 1937. Other papers studied were those (1 cc. of 0.005 percent) was adopted. of C. K. Johns (3) , Central Experi­ Preliminary studies also indicated that mental Farm, Ottawa, of A. Moldavan an intermediate pink color could be read ( 4) of the Guaranteed Pure Milk Com­ fairly uniformly by several workers, C?D· pany of Montreal, Canada, and of G . A. sequently, this color, a pronounced pmk Ramsdell in the Tenth Annual Report of but not a vivid pink, was selected as the the New York State Association of Dairy end point. and Milk Inspectors (5). It was essential to establish the rela· All the above mentioned workers and tionship between the reduction of. ~ethy· papers have indicated that the resazurin lene blue to white and of resazunn 10 test is very useful in the control of raw pink as well as the relationshiJ? of res· --;-p;esented at the Twenty-seventh Annual Meeting azurin pink to other bacteriologural tests. of the International Association of Milk Sani· These objectives could be worured out !.:.dans. Cleveland. Ohio, October 19-21, 1938. 4 1 2 14 1 2 s 3 4 3 2 3 JOURNAL OF MILK TECHNOLOGY 239 did not agree completely, only one pair duction times with the two dyes. The good or poor milk. They arc presented according to their reduction times. The of samples differed by more than 50 per­ times for complete reduction (to white) in Table 2. results are compiled in table 3. cent, while 9 other pairs differed by 25 of the two dyes were fa irly similar. It TABLE 2 The reduction times of the resazurin percent or less. Seven pairs of samples is interesting to note, however, that the Compm·ison of reduction times of methylene and blue were grouped on a 1 to 2 basis ( 16 percent) differed by more than 2 5 methylene blue reduction time was longer blue and resazurin to pink on tank car milk because the averages of the 230 samples percent and by less than 50 percent. with the good quality cream and shorter s hipmmts. were 2.39 and 5.17 hours respectively. Agreement Disagreement Only in one instance did the 0.05 per­ with the poor quality cream than the re­ of resazurin of resazurin The methylene blue reduction times were cent resazurin show a longer reduction duction time of resazurin to white. Com. pink pink more than double the resazurin reduction time than the 0.005 percent solution. pared with the reduction ,time of resazur­ Group No. % No. % times in groups 1, 3, and 4. In these The data indicate that reduction times in to pink, there was more difference Methylene blue, three groups the agreement between the to pink of the 2 strengths of resazurin with methylene blue than with resazurin 6 hours or more; two tests was closer than in group 2 solution (when the amounts of the dye white in the highest quality groups and Resazurin Pink, where the spread between the two tests 4 hours or more 38 92.6· 3 7.4 itself are equal in both) are closely com­ less spread with methylene blue than Methylene blue, was less. The agreement of the two parable but that a slightly slower reduc­ with resazurin white in the poorer qual­ 4 to 5% hours; tests for the 230 samples was 76.08 per­ tion may be expected with the 0.005 ity groups. There was a close agreemen·~ Resazurin Pink, cent. It is interesting that the highest percmt than with the 0.05 percent soltt­ of the methylene blue and resazurin re­ 2 to 3% hours 9 64.3 35 .7 agreements were shown in the highest tion. ductions to white in all the intermediate In this set of results the reduction times of quality and the lowest quality groups. merhylene blue to white and resazurin to white COMPARISON OF REDUCTION TIMES OF groups. The t·esults wortld indicate We may conclude from these t·esults that of 55 samples were 7. 31 and 7. 31 hours re­ RESAZURIN AND METHYLENE BLUE that for practical purposes the reduction spectively. the average time of ,·eduction to pink is To establish a relationship between the times of methylene blue and resazurin to The average of the reduction times to pink approximately half the methylene bltte two dyes, duplicate samples of raw cream white on vat samples of raw 35.0 and of the 55 samples was 4.95 hours, the relation­ reduction time on patrons' t·aw milk. were run with the 0.005 percent res­ 40.0 percent cream are equal; while the ship being resazurin to blue 1 : 1.48. above reductio·n times are generally RELATIONSHIP BETWEEN REDUCTION azurin and triple strength (3 tablets in The results indicate that 92 percent of TIMES OF RESAZURIN TO PINK, AND MI· 200 ml. of sterile, distilled water) methyl­ d~uble the reduction time of resazurin to pink. The· relationship of resaz111in 55 tank car shipments were graded good CROSCOPIC AND PLATE COUNTS ON TANK ene blue. The cream samples were taken by both tests. In the fair milk group CAR SHIPMENTS OF RAW MILK from 200 gallon, full vats of raw cream pink to methylme blue white may theu­ there was a 64.3 percent agreement. The Having established comparative reduc­ just prior to pasteurizing. The results fore be considered 1 to 2 for vat sampler data show also that the average reduction of rau; cream. • tion times for methylene blue and res­ secured from the study of 151 samples times of methylene blue and resazurin to azurin to pink, it was considered import­ are presented in Table 1. A further comparison of the redu!Ofion white were equal, being 7.31 hours, while ant to compare the resazurin reduction The above grouping on the basis of the times of methylene blue and resazu.rin the average reduction time of methylene to pink with bacterial counts. The mi­ reduction time of methylene blue shows to pink or white was made with ta~ car blue was 1.48 times the average reduction croscopic counts were selected because not only the quality of cream which may shipments of milk. These data were time of resazurin to pink. they were made in connection with the be separated from raw milk ·of varying grouped to determine the agreement be­ The relationship of the reduction type. studies. Groups, pairs, and chains qualities but also the corresponding re- tween the two methods in picking out times of resazurin pink to methylene were counted as single cells. The data blue was 1 to 1.48. secured on 134 samples of patrons' raw TABLE 1 Additional information on the rela­ milk are assembled in four groups in Compariso11 of reduction times of resazurin to pink and white with the reductio1z time~ of tionship between methylene blue and res­ table 4. methylene blue on batch cream shipments azurin pink was obtained on patrons' Reduction time Factors based on A standard of 3 hours or more for Methylene in hours red. time of resazurin shipments. The samples were grouped resazurin pink was considered equivalent blue range No. of Methylene Resazurin to pink as the unit in hours samples Blue White Pink M.B. R.W. 'R.P. TABLE 3 7.5 to 8 11 7.91 6.47 3.52 2.25 1.83 1.0 (excellent) Comparison of red11ction times of methylene blue to white and resazltfin to pink 0 11 patrons' milk 6.5 to 7.25 15 6.75 5.75 2.58 2.61 2.23 1.0 Ave. Agreement Disagreement (very good) Group Hrs. Factor Number Percent Number Percent 5.5 to 6.25 17 6.09 5.63 2.54 2.40 2.21 1.0 M. Blue, 6 hrs. or more 7.35 (good) Resazurin, 3 hrs. or more 3.49 2.10 84 83.1 17 16.9 4.5 to 5.25 39 4.90 5.04 2.23 2.20 2.25 1.0 M. Blue, 4-5% hrs. 4.85 (fair to good) Resazurin 2-2% hrs. 2.82 1.71 29 52.7 26 47.28 1.0 M. Blue 2-3% hrs. 2.98 3.5 to 4.25 38 3.82 3.99 1.75 2.18 2.28 2.22 (fair) Resazurin 1-1% hrs. 1.34 31 72.1 12 27.9 2.5 to 3.25 22 2.90 3.34 1.42 2.04 2.35 1.0 M. Blue 0-1% hrs. 1.22 2.39 100.0 0 (poor to fair) Resazurin O-% hrs. 0.51 31 0.0 1.0 Average 0.0 to 2.25 19 1.37 1.75 0.75 1.83 2.33 5.17 2.16 of 230 Samples 2.39 175 76.08 55 23 .92 (poor) .. 240 RESAZURIN TEST JOURNAL OF MILK TECHNOLOGY 241

TABLE 4 that four hours was not too high a average reduction times for resazurin pink Relationship between redurtion times of resazurin to phzk and microscopic forcclard to set for fresh tank car ship­ of 5 - 6 hours have corresponding plate raw milk jtJll leaving country plants. Only counts under 100,000 bacteria per ml. I Relationship of reduction 1 Results of tests secured in the city No. % under iiJCil ~al Grade" shipments were made Group Samples 400,000 "5~ g July and this accounts for the laboratory from the same tank car ship­ ll A duran. h aYerage re d'.uct10n time o fh. t e mne ments discussed in table 5, plus tests Resazurin reduced in 3 or more hrs. 47 43-91.5 from tank car shipments from other B 3- 6.39 IUS les checked during that period. At­ United Farmers plants are given in table Resazurin reduced in 2-2% hrs. 32 18-56.25 ~tpon is drawn to the close agreement of c 3- 9.37 (CCIIrage reductiOn• times• f or t h e two up- 6. Resazurin reduced in 1-1% hrs. 34 5-14.70 J'e cades in the months of April, May, The data summarized in table 6 com­ D 4-11.76 gJune. Logarithmic averages of the pare closely with those in table 5. Eighty­ Resazurin reduced in O-% hrs. 21 cd 0- 0.0 3-14.27 late counts on 91 samples which were one samples tested in May, June, and TOTAL 134 66 13 r ed in April, May, and June, and July and having resazurin reduction time hich were over 4 hours on the res­ of 5 to 6 hours had comparative plate :zurin test, were under 100,000 bacteria counts under 100,000 bacteria per ml. to a methylene blue reduction time of ~s good q1tality milk as is considered over 6 hours. This has been considered mi. In the 3 - 3.75 hour groups for Twenty-six sampl-es in the 3 to 4 hour 1Sfactory on the basis of the melbv,r...... •:.. ~ three months, the logarithmic averages group had logarithmic aver-age plate fo~ many . years, satisfactory for marke~ blue or the micros co pic tests. milk. Thts grouping should agree \\CCC 430,000, 480,000, and 360,000 hac­ counts of 330,000 to 380,000, while three therefore, with the generally accepted RELATIONSHIP BETWEEN ria per ml. ~;espectively. There are in­ samples in this group averaging 3.58 uflicient samples reported in the 2 - 2. 75 hours had a logarithmic average plate plate count standard for raw market milk TIMES OF RESAZURIN AND PLA1lE COU count of 120,000 bacteria per ml. With delivered to the Boston Market of uncle; ON TANK CAR SHIPMENTS OF hour group to be considered. There was more than two hours difference in the av­ this last mentioned exception on the small 400,000 bacteria per mi. ' Tank car shipments of milk The results_ show that 91.5 percent of eroge reduction times of the two upper number of samples, th-e results are in the Morrisville, Vermont, plant- 001~" • ~:.: raaes of milk during April, May, and line with those of table 5 and show that the samples m Group "A" had micro­ the months of April, May, June and scropic c~:mnts below 400,000 while no fune and a corresponding difference of samples having resazurin pink tests of 5 of July were checked by the more than 300,000 in the logarithmic to 6 hours h~ve comparable plate counts sa?Iples IL?- Group "D" belonged to this test and by the plate count mtcroscopK-count group. Only one of averages of the plate counts for the same of less than 100,000 bacteria per ml. Methods) . The results are "'"·"1"'"'"''"' 47 Group "A" samples had a microscopic ).i!Jlples. Such tests would indicate a raw milk of and compared in tab,k _'5. The remits show that samples having excellent quality. count of more than 1,000,000, while 18 Of the 110 individual tank of 21 Group "D" samples were in this checked by resazurin, less than sl iOtmptleS> :~ class. The remits indicate that a res­ cent showed reduction to pink in TABLE 6 azttrin pink of 3 hom·s or more represents than 4 hours. It was considered Rtlasionship between reduction times of resazttrin to pink and bacterial ·plate counts on tank car milk shipments. !ooth of Reduction time of No. samples Average hours Log. average TABLE 5 hipment resazurin to pink in group reduct. to pink of plate counts Relatio1zshi p betwem reduction times of resazuritz to pink d b · 1 l . an acterra p ate c01111u on J1 11 April 4 hrs. or more 11 4.66 320,000 ta11 k ca1· shrpments of raw milk 3-3% hours 11 3.31 380,000 Month of Reduction time of No samples Ave h Shipment · · k · rage ours 2-2% hours 1 2.50 390,000 resazunn to pm in group reduct. to pink 0-1% hours 1 1.50 1,400,000 April 4 hrs. or more 11 5 "9 ~lD.y 4 hrs. or more 35 5.63 98,000 3 - 3~ hrs. 2 3:~8 3-3% hours 7 3.46 350,000 2-2~ hrs. 3 2 25 2-2% hours 1 2.50 355,000 0-1% hrs. 0 · 0-1% hours 0 May 4 h;s. or more 42 ~ . 80 JWI~ 4 hrs. or more 40 5.40 93,000 3-3 J4 hrs. 3 3.40 3-3% hours 8 3.31 330,000 2 -2~ hrs. 1 5 55 2-2% hours 1 2.75 320,000 0-1% hrs. o o· 0-1% hours 0 II June 4 hrs. or more 38 5.80 July 4 hrs. or more 6 5.92 82,000 3-3~ hrs. 5 3.45 3-3% hours 3 3.58 120,000 2-2~ hrs. 1 2 75 2-2% hours 0 0-1% hrs. 0 o' 0-1% hours 0 July 4 hrs. or more 9 7 61 87,000 Summary 4 hrs. or more 92 160,000 3-3% hrs. 0 o' 3-3% hours 29 270,000 2- 2% hrs. 0 o Results secured in Boston laboratory on samples taken from tank car shipments upon their 0-1% hrs 0 0 rriv:U in the city. Summary 4 hrs. or more 100 5 62 Ave. of pinks, 4.91; Ave. of Whites, 6.42 3-3% hrs. 10 3:41 Rtlationship-pink : white:: 1 : 1.31 243 RESAZURIN TEST JOURNAL OF MILK TECHNOLOGY

RELATIONSHIP BETWEEN THE REDUCTION of :> hours or more are considered N('("\11"\0 TIMES OF RESAZURIN TO PINK, AND MI­ cellent. ex C()O\V"'\t­ N('("\ 11'\ \0 I I I I CROSCOPIC COUNTS AND ACID INCREASES A careful study of the logarith . ~~~~ OF VAT SAMPLES OF CREAM averages of the microscopic counts h ma 5 The resazurin test was applied to vat that they varied from 190,000 to 1 0~915 samples of raw cream and compared to 000 bacteria per mi. from the top ' ~ the microscopic counts on the same cream to the bottom grade cream. U:h~ gSra e · d' h tun before pasteurizing, and to the incuba­ mary ~n tcates t at rmv cre4f!'l Jampl, tion tests on the cream after pasteurizing. averagmg about 2 ho11rs with resa The samples were taken from 200 gallon pi':k ( 4 h?urs with methylene blne) z;:;~ batches of cream just before heating m~crosco pte co11nts averaging, logarith. mtcally, from 1:)0,000 to 480,000 bact · commenced. The resazurin sample and 0000 oooo 0000 per ml. trl;t 0000 oooo 0000 the 1/100 mi. quantity for the Breed 0000 oooo 0000 o"o" Oo.. 6666 0000 0\ t- -qo V'\ count were taken from the bottle imme­ Comparing the average acid rises ('('\('I o. ~ G\OONO ...-4Nrf\V"\ N-c;t'\ON.., ..... N-..:rO... diately. The pasteurized samples were incubation with the 4 resazutin grou;: ...... held m ice water until 5 P. M. when one can see that they are consistent fo 1 the samples were placed in the incu­ the ~ monthly periods .and increase pr: bator. The incubation time was 14 gresstvely as the resazunn reduc:tion tim hours and the temperature was adjusted decrease and as the microscopic coun -..rN""'OO G\ OOif"\0 V"\V'\00 0 "¢t-OV"\ 0000\0\ ,.....;'-!)~r..: r('\Q.....; N No\r--:....0 fro~ time to time depending on the increase. However, there was not ave v\6000 ...-\00.0 V"\'-!)r"--0\ "¢'\1"'\'-00 '<1"\0t-0 t-000\0\ ~V"'\V"\0\ quality of the cream. The incubator definite or close correlation between J...... temperature desired was one which duction times and acid increases on th would cause at least a titratable acid in­ individual samples. This lack d£ definit

crease in all the samples. Differences in cor:el~tio~ is no ·doubt due to the gr~ 0 ' percent of all the samples These data show that 54 duplic.at :> ri ri were in the hour, or more, group and samples taken approximately 20 hour ...c: ...c: :>5.2 percent in the 2 - 2.75 hour group. vu)viui Cl.Jv.iv.i~ apart by the two laboratories gave res· ~ \-c \..4 4 O,..c:...C:...C:\..4 4 ""'\-1 o...c:...c:...c: In other words, 53.5 percent of the cream azurin times which differe•d one hour or 6..,.,.,."' 8 , ..,. ,..,., ..,. samples were over 2 hours on the basis .... ~~~ \..4 C'O...... t<"'...... «''...... less. Three of these pairs of. sampl ocr 1 , ON.-< of resazurin pink. This would indicate, gave similar reduction times. The di52· ('(')Nr"'40 ,.,rl, J.6 by reference to the 1 : 2 relationship of greements in the other 51 duplicates va~ resazurin pink to methylene blue white ing from 0.25 to 1 hour were evenly da (s·ee table 1), that 53.5 percent of the vided between the two laboratories, indi cream samples would stand up 4 hours or eating that either the quality Of the read more with the blue test. Cream in these ing or both may have varied. However

TABLE 8 Comparison of c~ untry a11d city results on same tank car shipments of milk- Diff. V-i hour Diff :y, hour D .ff 20 houri tiP., Agreement Country City Country 2 City Cou~t;y 1 hocft f?iii. over 1 t, 3 + 8 +6 + 13 +u + Y ountry 4.12 % 14.43% 24.74 % 6 +7 +31 Recent Advances in New Jersey Dairying and the . I . 15.46% 41 of.t + mean1ng anger ttme. .24% Direction of Future Developments * David Levowitz ?1 showed up better in the country than m the city. !his .would suggest that 7. A resazurin pink of 3 hour Director, New Jersey Dairy Laboratories, New Brunswick, N.J. when readmg appreciably, more represents as good quality. 'Jk or ~he d1sa~ree~ a 5.5 hour methylene blue test Ill! the~e likely was a d e ten~ratJ'?n in quality MASTITIS CONTROL ilizing milkers' hands and cows' udders 8. Samples having resazurin pink dunn.g the 20 hour agmg m transit to Laboratory methods in general use are stressed. A simple wooden rack of 5 to 6 hours have corres ~ the City. have shown that not all milk which which is easily carried from one cow to plate counts of under 100,000 P~~-~ another, and which holds a pail of chlor­ The . comparisons of duplicate tests per mi. u"Ue~ comes from animals whose udders are made m the two laboratories indicate not visibly swollen or whose milk is ab­ ine sterilizing solution in which are im­ 9. A predominance of the sam J mersed a number of wash dothes equal that when the quality remains about the batch, raw cream having resaz ol normal in appearance is "milk from .P es to the animals to be milked, a pan for sa~e, the r_esaz~rin test can be read quite tests of 2 hours or more havunm pink healthy animals". The "blinding" of a uniformly m different laboratories where · e llliC!fO. cow's udder creates a very definite loss of the disposition of the individual cloths, scopic counts averaging, Iogarithmicall the same standards are followed. farm economy, since the maintenance of a black sheet fore-milker device, and a 150,000 to _bacteria per mi. 'J 3~0 , 000 the cow remains a constant 100% while brom-thymol-blue kit are shown and CONCLUSIONS 10. There IS an Indefinite correlati the return can not exceed a maximum of demonstrated in actual use. The milker 1._ One Milliliter of 0.005 percent res­ between the .acid rises developed w.:! 75%· sterilizes his hands by ringing out the azunn dye mixed with 10 mi. of milk or fresh _pasteunzed cream is incubated During the past year a voluntary mas- individual wash cloths. The potency of approximately room temperature fo creal? makes a convenient and practical titis control and eradication program has the chlorine solution is maintained by quality-control test and gives uniform re­ hours and the resazurin reduction t~mes been initiated through the cooperation of preventing the entrance of organic mat­ sults when carried out under definite and of t?e ~arne batches of cream before M t.. teunzatwn. r-- three New Jersey agencies. These agencies ter into it. ·The wash doth after once standardized conditions. are the Bureau of Animal Industry of the being used 'to wipe a cow's udder is 2. The reduction times of 0.005 per­ . 11_. The resazurin test can be ~·"~ ... ~ .e­ State Department of Agriculture, the placed in the pan supplied for that pur­ cent resazurin and standard methylene m different laboratories with uniform " Dai.cy Extension Service of the Agricul­ pose. The ·first stream of fore-milk from blu~ {1 tablet in 200 mi. of water) to suits when the methods are standardized, tural Experiment Station, and the Dairy each quarter is examined by the black white are approximately equal. REFERENCES Department of Rutgers University. The strip fore-milker. The brom-thymol­ 3. The r~duction . time of 0.005 per­ l. Barrett, W. D., Rutan, H., and purpose of the program is to educate New blue test kit is used for milks which show cent resazurm to pmk is approximately J. A:, ~h_e ResazQiin Test-Its Jers~ producers in the practices de­ any abnormality, and brom-thymol-blue 2/3 the reduction time of methylene PractJcabll1ty as Applied to the signed to prevent infection of animals tests of all quarters of all cows are taken blue when used on fresh tank car ship­ Control of Raw Milk, f. Dairy at regular intervals. 705-709 (1937) . and in the methods of identification, iso­ ments of good milk and slightly more 2. Fay, A. C., Director of Laboratories aDd ~ lation, and care of animals found to be The voluntary mastitis control program than 2/3 of the methylene blue when search, H . P. Hood and Sons ailing. Demonstrations are made before has met with extraordinary response. lt used on the same tank car shipments one Mass. Personal discussion of unpubl' farm groups in which the principles of is believed that if legislation is passed day older. data, 1938. maintaining a clean herd are discussed. for complete eradication of mastitis, the 3. Johns, C. K., Measuring the Bacterial . 4. !he reduction time of resazurin to 1ty of Raw Milk. Paper presented Trhe use of ledges between stalls to avoid New Jersey dairy industry will not be pmk IS approximately one-half the meth­ Fifteenth Annual Conference for the movement of one animal's bedding to found in a position similar to that which ylene ?Iue te~t ~m patrons' shipments of Plant Operators, University of "··-~· · · another's place, and of individual water existed at the time that tuberculosis erad­ raw milk. This IS a wider ratio than with Burlington, November, 1936. cups and feed bins is shown to be a ication was ordered. tank car shipments. 4. Moldavan, Andrew, The Resazurin factor in the avoidance of transmission of Paper presented at the Sixteenth ARTIFICIAL INSEMINATION 5. There is a high agreement between Conference for Dairy Plant Operators, infection. The relationship between the the resazur!n pink . and the methylene versJty of Vermont, Noveml:>er, 1937. readily used farm methods for identifi­ Artificial insemination of live stock blue tests m selectmg good quality or 5. Ramsdell, G. A., The Resazurin Test for cation of ailing animals and the more has been a theoretical possibility for many poor quality raw milk. Sanitary Condition of Milk. Tenth An~~-·~ elaborate laboratory techniques is also years. The practical use of artificial in­ Report, N. Y . State Association of 6. A high percentage of patrons' milk and Milk Inspectors, pp. 57-68, 1936. demonstrated. The advantages of ster- semination with dairy animals has been samples that test 3 hours or more with retarded by the inability to maintain 6. Ramsdell, G. A., Johnson, W. T., -• Condensed from the paper of the same title pre· resazurin have bacterial counts of less Evans, F. R., Investigation of Resazurin sented at the 23rd Annual Meeting of the Central spermatazoa for extended periods, and than 400,000 per mi. an. Indicator of the Sanitary Conditions ~tla ntic States Association of Dairy, Food, and to dilute the seminal fluid without affect­ 18, ~g Officials, on May 19, 1939, in New York MJ!k, f . Dairy Sci, 705-717 (19"}· C1ty (Hotel McAip;n) . ing the virility of the sperm cells. 'fbe ability to ferment lactose with the dissemination of unsound dairy products In 1935. Dr. Elie Ivanov found that OXIDIZED FLAVOR of gas, possessed by some or­ have included establishment of require­ spermatazoa could be kept virile for ex­ A number of unrelated theories ; ~lllu'••···-w-hich .are not completely des- ments for the sterilization of restaurant tended periods by their storage at low the cause of oxidized flavor are avaii:t, pasteurization, had led to the and soda fountain glasses, ice cream dis­ temperatures. Another Russian worker, A conclusion which has been estabr h complete American Public pensing equipment, etc. Samples taken 15 Professor S. Milovanov, reported in 1936 by all investigators is that su.tnmer ~ Asosciation (1) procedure, rath~r of products sold over retail counters have shown that contamination at the point of on diluting media which did not affect is less susceptible to oxidized flavor : the presumptive_ test alone, to av?td sale frequently assumes mammoth pro­ the virility of sperm cells. Russia began winter milk. New Jersey eclucaf " onfusion resultmg from reportmg portions. using artificial breeding on a practical agencies have therefore attempted t~o~ the t1 e positives. The samples should crease the prevalence of oxiaized fl 011 The number of roadside stands along basis in 1937. Denmark followed, and f:r:bly be obtained directly fr?m the by making_ the mater~als characteristi~v pre essing plant. The preparatw~ of New Jersey's key highways has increased, Professor E. J. Perry, Dairy Extension or s~mm~r mtl~ prodpucttfon available durin P'1k supplies which poss~ss no coh~orm due to the New York World's Fair. The Specialist at the Agricultural Experiment t e wmt~r time. . ro ess?r C. B. Bend Jill ·srns in 25 rnl. portwns necesstta_tes control of dairy products and of the Station of New Jersey, observed the func­ (2) Datry Feedmg Spectalist at Rut tt organtbsolute sten'1' tzatwn . o f processtng manner of their dispensation at these tioning of the first Danish breeding unit University,_ has sho:vn that the feer.:! !he· aroent and the maintenance of truly establishments has been arranged for, immediately after its organization. of grass silages durmg the winter mai 13 tqUI~c co~ditions throughout the period through the cooperation of local and I Artificial breeding offers a number of tains summer flavor and color in n '{Pplant operation. The records of a state officials. .I advantages to the dairy farmer. By the milk_ to an ext~nt unparalleled by norm rober of plants show many days when feedmg matenals. A campaign of ed ~bis result has been achieved. ~o pl~nt DAIRY PRODUCTS CONTAINERS AND selection of bulls which possess good CLOSURES blood lines and eating New Jersey dairymen to 'the mao. h yet been found where a coltform In­ which have proved their A consideration of the closure problem ability to transmit high milk production ner of preparing grass ensilage has d: of 0 per 25 mi. has been maint~ined prosecuted vigorously during the definitely but the order of magmtude by New Jersey agencies in the past year and good health, many animals can be year through the county extension :r colifor~ concentrations has been kept has led to the following reasoning: The inseminated without any strain. The working under the direction of p rery close to that value, whenever these primary purpose of a dairy products mechanism involved in the establishment Bender. The processing plants, too ~!ants do show the positive presence of closure is to prevent the entrance of con­ of a breeding unit consists of organizing been receiving instructions as ifo th~ the group in their fluid products. taminating materials into the prod~ct twelve hundred to fourteen hundred ner of handling of milk supplies so t New Jersey health officers have be~n under the conditions of commerCial cows under the care of a veterinarian. there will be no damage to fla\t well satisfied with_ the pr_ogress made ~n handling. The first criterion to be ap­ This veterinarian examines all animals through processing. It is interes~ing lowering the cohform mdex; . at fl.utd plied to a closure, then, is th~t under before_ they are to be impregnated to de­ note here that anti-oxjd~nts developed ~ product plants, and are now g1vmg some normal icing, storage, transportatton, and termine whether or not they are in prop­ other industries have been used sue ention to other ~airy manufactures as delivery, efficient closures would be those which would resist the entrance into the er physical condition. The seminal fluid fully in the experimental ell. Much has been done with ice product of what~ver might be car~ied in is recovered from a bull by bringing it of oxidized .flavor in market milk. ream plants, where. the contamination though Avenex Conceptrate has of old ~e homogemzer heads has been the ice as a vehtcle. The protectiOn of into the pres·ence of an animal in heat used most successful.trin eoll1mercial po1'ent factor. Legislation similar t_o the pouring lip is, then, a secondary cri­ and obtaining the seminal discharge by cream manufacture for this that adopted in the New York metropolt­ terion, since closures which allowed the means of an artificial vagina. The sem­ has not yet been accepted for use un area, requiring "sanitary head" homo­ entrance of c9ntaminants into the product inal fluid thus obtained is standardized to Jersey milk supplies. genizers is under considera~i?n. . The must have also contaminated the pouring a definite concentration with one of the practice of complete stenhzat10n of lip. . special diluting formulas. The dairy THE COLIFORM INDEX freezers and packaging machines has been The methylene blue drip technique h~s animals which come into heat during the The convenient Scharer ~4) incorporated into the routine of many shown that capillary creep and ~smotic next seven days may then be impreg­ tion of the phosphatase test dP,,t>lc• ne~l,. plants. Considerable difficulty is still transfer are important factors m the nated with this solution. It has been during the past year has given being found by the persistance of the functioning of a dairy products closure. found that the percentage of impregna­ control officials a rapid efficient practice of ruining good ice cream mixes The technique possesses limitations, how­ tion is much htgher with this method for checking proper pasteurization. by the addition of contaminated colors, ever as far as the entrance of foreign than with the orthodox method. In ad­ the absence of heat resistant species, fruits and flavors just prior to freezing. mat~rials into the dairy product is con­ dition, diseases can not be transmitted the constitution of a medium which cerned, for a relatively large amount ?f from cow to bull and vice versa. The vates the thermal death point of t he CONTROL OF RETAIL OUTLETS material must enter in order to show It­ artificial insemination technique has been form group, many New Je~sey llealtb During the past few years, many New self. To avoid this, a modification of accepted to such a degree that there are partments have adopted the jffsey control divisions have adopted leg­ the technique has been developed which now four units operating in New Jersey tion that the presence of coliforn:t lation requiring the serving of individ- employs the use of a bact_erial cult~re .. alone. There are fifteen units already ganisms in pasteurized da' ry s ~:~pphes 1111 packages of milk to consumers at The entrance of even a mmute portton established in other sections of the coun­ evidence of incomplete sanitat~on _of fdail outlets. Steps taken to avoid the of the culture into the dairy product will try as well (3). equipment used after pasteuntzatton. NEW JERSEY DAIRYING 249 show its·elf by the recovery of the or­ error, since more than 100 bottles are ganism from the product. The proce­ included in the usual assortment of three dure consists of developing a culture of cases of quarts, two of pints, and two of B. prodigiostts Flugge (Serratia marces­ half pints. The information obtained The Nutritional Properties of Milk * cens) . This organism has been selected has been extremely valuable to show clo­ because it is never found in properly sure manufacturers how modifications of C. P. Segard pasteurized products, and because it de­ standard designs may influence closure Wisconsin Alttmni Research Foundation, Madison, Wis. velops large characteristic colonies when efficiencies. cultured in a suitable manner. The cul­ For over 2000 years including the Since milk then is produced naturally ture is diluted with water and frozen THE DIRECTION OF. FUTURE 1830's, scientists spoke and wrote of only as the only food containing some of all into ice. The concentration of organisms DEVELOPMENTS one kind of food. A medical text book our known food factors, it is natural to in the ice is determined and the ice is From present indications, New Jersey's of 1834 is the first mention of three expect a better product from a nutritional then mixed with normal ice to yield a next thoughts in dairy sanitation will be kinds of foods. Those three are the point of view than from those foods we concentration of 500,000 organisms per along the lines of homogenized market bulk foods. Then in the next 60 years adopt and adapt from animal and vege­ gram. The bottles of dairy product, milk, high temperature - short time pas­ came a slight change which included table life. after having been sealed with the closure teurization, and soft curd milk. iron, calcium, and a few others. But with­ When these points are considered we under consideration, are packed in cases, BIBLIOGRAPHY in the last fifteen years we have come to can readily understand why milk of all iced according to the normal manner, 1. American Public Health Association. StaniJ­ realize there are forty or more substances foods has been and will continue to be 'I given agitation equivalent to four hours ard Methods fot· the Examination of Dairy that must be classed as necessary foods, the most studied and most safeguarded of transportation, then held at room tem­ Products, Sevemh Edition, 70-81, 1939. or rather fo@d factors, since ~uch very food. More money is spent on safe­ perature for four hours (equivalent to 2. Bender, C. B., and Tucker, H. H. Ensiling small quantities of many of them are guarding milk than all the other 300 odd the length of time bottles remain unre­ green crops with molasses, New Jersey Agr. required. How many of these are as yet foods combined. The public has yet to frigerated after delivery from a route Exp. Station, Extension Bulletin No. '198, cl938. undiscovered is of course unknown. recognize this important point. wagon) then placed into a refrigerator The main source of these food factors uniced for four hours. The contents of 3. Perry, E. ]. .l}rtificial insemination of dairy is naturally the material we eat as food. FOOD FACTORS the bottles are then cultured for the pres­ cattle, New Jersey Agr. Exp. Statiotl, Ex­ tension Bulletin No. 200, 1939. And if our food does not contain them, Many elell,lents are classed as food ence of the chromogenic organism. Seven or enough of them, the body will be de­ factors. Minerals, such as iron, copper cas·es of bottles are stacked to parallel 4. Scharer, H. Improvements in the rapid phosphatase test for detection of imP,roper ficient of that particular factor and a and iodine, and elements such a chlor­ commercial handling conditions. This pasteurization. f. Mil~ Techno/. l, 5, 35-38 sub-normal condition develops. In many ine, potassium, and sodium are needed procedure also reduces the experimental (1938). instances the amount is small and the by the body but in such small amounts lack of it may go unnoticed for some that they were ~formerly considered of time. The needed amount of calcium is little importance. Yet the science of nu­ one-half pound a year, so what appears trition has shown their value and that to be a very slight decrease in-· we cannot do without them. Silos - Types and Construction !he daily requirement may go unnoticed While they are all present in milk as for some time. It may never be noticed. a usual thing, it is easy to understand A new Government bulletin on the different kinds of silage are given. Extra But it cannot but mak€ a difference in the that anyone or several might be missing. types and construction of silos has just reinforcement is recommended for walls state of health of the individual. And No mineral element can appear in the been issued. It should be of interest to of silos to be filled with silage made milk is the only food that can supply a milk that is absent in the food of the all directly concerned in dairying or live­ from sunflowers, pea vines, hay, an d! mo­ sufficient amount of this mineral in the cow producing the milk. That statement stock farming. The bulletin deals with lass·es, or from corn very high in mois­ portions ordinarily consumed daily. is not wholly true but the exception only the various kinds of above-ground and ture. The danger from fermentation gas In nature, the position of milk is gives weight to the statement. The ex­ below-ground silos, and carries the neces­ in the silo receives special attention, and unique. It is the only food that has but ception is that the cow will continue to sary details of construction, with handy means are suggested in the bulletin. for one function, namely, that of a food. supply for a short time some minerals in ta:bles of dimensions and helpful illustra­ insuring saJety and for reviving victi~s. Plant products have other functions the milk that she is no longer receiving tions. Sections of nine types of silos are This publication, Farmers' Bulletin whether it is root, leaf, fruit, seed or in her feed. She is then supplying from shown. The new bulletin supersedes 1820, may be obtained free while the blossom. That function ceases when we her own tissues the mineral that she her­ Farmers' Bulletins on pit silos and home­ supply lasts by writing to the Office ~f harvest it for food. The same situation self needs. made silos. Publication, U. S. Department of Agr1· holds for animal foods. They too have The milk of a number of animals is Construction needs for silos to hold culture, Washington, D. C. another function in nature. used by people in various parts of the world. The animals usually selected is -' Presented at Twenty-seventh Annual Meeting of the one that gives a fair amount of milk International Association of Milk Sanitarians at Cleveland, Ohio, October 19·21, 1938. with the least care. In North America JOURNAL OF MILK TECHNOLOGY 251 the animal selected, the cow, is the high­ era! element in nutrition. As the amount est producer of all the milk-producing of copper decreases in plants due to a important supplier of vitamin A. Again, tamin-like compounds. And milk offers animals. Several factors operate in the decrease in the soil and a deficiency in where the particular breed of cow gave bacteria an excellent source. When we selection of the animal used. Today we fertilizers, its importance in milk becomes less of the yellow pigment the milk usu­ realize however that bacteria consume an find some increase in goat milk con­ more pronounced. With the elimina­ ally contained more colorless vitamin A. am~>unt . of food . equal to their own dry sumption. Its grading is approaching that tion of copper in canned food processing wetght m five mmutes, and consume just of cow's milk. the amount of copper in milk takes on a~ DIGESTIBILITY about double their size and weight in FAT added nutritional significance. When we speak of the nutritional twenty minutes, another reason for clean There are a number of differences in value of milk another factor must be milk presents itself. The nutritional the milk of various animals and the nu­ VITAMINS taken into consideration, namely, the di­ value of milk is lowered where the count tritional value has been a point of con­ The third difference is not a quantit}l gestibility of milk. The increased interest is high. troversy. We are here calling attention factor as are the other two, since the in soft curd milk and the methods of se­ DIETARY EDUCATION to three of these differences. The first amount is exceedingly small and is no~ curing this are of more than passing in­ No substitute for milk has ever been is the fat content. The fat content varies measurable by the same methods. Two terest to the milk sanitarian. In order found. If its nutritional value can be with the growth requirements of the in­ of the vitamins, C and D, are present in to increase the digestibility of milk, three kept at a high standard by constant super­ fant animal. It varies from 1~3 per­ less than human requirements. These separate and distinct types of machines vision it will continue to remain at the cent in the ass and the mare to 54 percent two have been supplied from other food have been developed. Here again the head of the list of the necessary foods in the porpoise. (There are several sources - Vitamin C from all citrus milk sanitarian must become cognizant for growth and health. One factor that species of animals living in the sea that fruits, many vegetables, and some animal of the equipment that makes these must be kept in mind is "people are not suckle their young. They are not fish, of sources; and Vitamin D principally from changes. Not only the operation, but self-regulatory in their diet". They must course.) The milk of reindeer runs fish oils, until the discovery of ultra­ the equipment and the material as well be regularly told of the value of milk as about 17 percent fat and has probably violet irradiation. as the results to be attained by the process a food. You cannot depend on the in­ the highest fat content of natural milks In the case of Vitamin D, the situation itself require attention. stinct of the human to properly feed used by man. Infant animals must early is quite different. Two foods apart f.rom himself. There is a great deal of medi­ BACTERIAL ATTACK in life be protected from low tempera­ fish oils, namely egg yolk and milk, enzymes in milk by heat was methods were used in this work. fant animal. The normal human infant milk. The exhibition here this week known, and tests for raw milk and heated This study of the phosphatase test or doubles its weight in the first 180 days shows fully three times as much new milk were based on the destruction of the phosphomonoesterase test was sug­ of life. The calf of the cow doubles its equipment for increasing the Vitamin D enzymes ( 1), it was not until Leahy (2) gested by the statement of Tracy and weight in about 47 days. We should content of milk as that of several years reported a test for pasteurization of milk Hahn ( 6), "What effect does the growth therefore expect to find about three times ago. dep_ending upon destruction of amylase of organisms commonly found in pasteur­ as much minerals or ash in cow's milk The yellow pigment of milk is a good dunng the pasteurizing process and Kay ized milk have upon the accuracy of the as in human milk and other animals in source of vitamin A since this pigment and Graham ( 3) published the study of test?" This appeared to be quite im­ proportion. This is not exact but does is the pro-vitamin substance. Mi~ a!~ the phosphatase test for pasteurized milk portant, since during the processing of in the main hold valid for most animals. contains the colorless substance vttam•n that an effort was made to control definite­ milk after the milk is heated and held it The shift from copper to stainless A in considerable quantities. While ~n ­ ly the efficiency of a pasteurizing process is conducted through pipe lines, over steel and other .metals in the processing erally the liver can reduce the pro-vtt~ · by the use of the enzyme test. The two coolers, into balance tanks, botde fillers, of milk may have an important bearing min pigment to vitamin A, where thi1 methods that appear to give the most re­ bottles or cans before this product be­ on nutrition. Copper is a necessary min· function is impaired milk becomes an hable rc:sults are the Kay and Graham .comes ready for consumption. These parts method, dmribed by Gilcreas and Davis of the equipment may harbor some con- TABLE 1 organisms or some old milk. jected to the tests. The test organisms Phosphatase tests on samples of itwculated attd incubated milk may also be contaminated by used were B. lactictts, S. aureus, E. coli Kay-Graham Method• amounts of improperly pasteurized (2 strains obtQined from different Plate count ( Gilcreas-Davis) which contains some of these con­ sources), L. acidophilus, L. bulgaricus, S. Sample Test Colonies per cc. mgs. phenol/0.5 cc. lactis, B. mbtilis, and S. albus. Old No. Material B. I. A. I. B. I. A. I. organisms. The amount of pasteurized milk in many soured pasteurized milk (well mixed) 1 Control 36,000 110,000 0.02 0.02 was also used. Control samples of pas­ B. lacticus 3,500,000 0.02 may be in such small amounts that teurized milk, not inoculated, were in­ 2 Control 4,100 13,500 0.03 0.03 l!.O cannot be detected by the phospha­ B.lacticus 60,000,000 cubated and tested similarly. These data O.D3 test ... It is therefore of i~portance 3 Control 10,000 28,000 0.03 0.03 2.0 are presented in table 1. B. lacticus 10,000,000 0.02 determine whether any orgamsms that 4 Control 12,000 60,000 0.04 0.04 4.0 -.,fllf not be destroyed or may find their CONCLUSION S. aureus 600,000 0.04 .,, into the milk will produce or re- 1. The growth and presence of B. 5 Control 40,000 91 ,000 0.01 0.01 2.0 {tivate1 the phosphatase enzyme. S. aureus 350,000 0.01 ' To develop this problem, we proceeded lactictts, S. attretu, E. coli (2 strains ob­ 6 Control 75,000 210,000 0.02 0.02 2.0 tained from different sources), L. acid­ E. coli to introduce into milk various organisms, 10,000,000 0.03 a philus, L. bulgarictts, S. lac tis, B. sttb­ 7 Control 3,000 13,000 0.03 0.03 normally found therein and other 2:0 016 tilis, and S. albtts do not reactivate or in­ E. coli (strain No. 1) 20,000,000 0.03 :ganisms that. might find their w~y i~to 8 Control 7,500 80,000 0.02 0.02 1.5 ;JSteurized mtlk through contammatwn crease the phosphatase enzyme to any ·ex­ E. coli (Strain No. 1) 39,000,000 0.03 rn the processing. or handli?g of milk or tent where it would interfere with the 9 Control 16 000 60,000 0.02 0.02 3.0 test, neither does old, sour milk. L. acidophilus ' 10,000,000 0.02 that might remam on equtpment or re­ 10 Control 25,000 78,000 0.02 0.02 3.0 ctptades in the preparation of cultured 2. The pasteurized milks kept at an L. acidophilus 16,000,000 0.02 m.tks. Pasteurized Grade "B" milk was incubation temperature of 3r c. for 5 11 Control 12,000 20,000 0.01 0.01 2.0 hours do not show a reactivation of phos­ L. brtlgaricus 3,000,000 permitted to curdle by standing at room 0.02 phatase as measured by an increase of the 12 Control 2,100 18,000 0.02 0.02 2.0 temperature and was then thoroughly L. bulgaricus 12,000,000 0.02 shaken and also used as a testing medium enzyme. 13 Control 86,000 220,000 0.02 0.03 see what effect old sour milk would 3. The Gilcrease-Davis and the Scharer 2.0 10 L. bulgarictts 1,000,000 O.D3 have on the tests. At the same time, we methods compared favorably as laboratory 14 Control 15,000 75,000 0.03 0.03 3.0 S. lactis 3,000,000 0.03 compared the results obtained by the methods for ·the determination of the 15 Control 11,000 120,000 0.04 0.04 3.0 Kay and Graham (Gilcreas and Davis) phosphatase content of the milk. S. lacti.r 12,000,000 0.04 method and the Scharer method. Plate 16 Control 12,000 43,000 O.D3 0.03 . 3.0 counts were also made of the milks. Nu­ REFERENCES S. lactis 10,000,000 O.'lH trient Agar was the medium used for de­ 1. Leach & Winton, Food Ins-pection and An­ 17 Control 12,000 60,000 0.02 0.02 3.0 tennining the counts for all organisms alysis, 1920, 173. B. subtilis 300,000 0.02 2. Leahy, H. W. A practical test of pasteur­ 18 Control 40,000 52,000 0.02 0.02 3.0 but 'f.: coli. Levine's Eosin Methylene ization. 23rd Ann. Rept. lnternat. Asso. B. subtilis 100,000 0.03 Blue ~ ium was used for determining Dairy and Milk Inspectors, 1934, 93-108. 19 Control 16,000 60,000 0.03 0 . 0 ~ 7-0 the 'P.. coli counts. The incubating tem­ S. a/bus 120,000 0.04 ' 3. Kay, H. D. and Graham, W . R., Jr. A 20 Control 42,000 200,000 0.02 0.02 4.0 perature was 3r c. phosphatase test for pasteurized milk. J. S. a/bus 300,000 0.03 Dairy Restarch, 6, 191, ( 1935). 21 Control 6,300 12,000 0.01 O.ot 1.5 EXPERIMENTAL PROCEDURE 4. Gilcreas, F.· W. and Davis, W . S. The E. coli (Strain No. 2) 12,000,000 0.01 Specimens of New York City Grade practical value of the phosphatase test for 22 Control 14,000 ·68,000 0.02 0.02 3.0 "B" pasteurized milk from different pasteurization. 11th Ann. Rept. New York E. coli (Strain No. 2) 5,000,000 0.02 State Assoc. Dairy and Milk Inspectors, 83. 23 Control 16,000 76,000 0.04 0.04 2.0 dealers were used, and each milk before inoculation with the test material was 5. Scharer, Harry. Phosphomonoesterase test Old Milk 1,200,000 0.04 for control of dairy pasteurization. J. Dairy 24 Control 24,000 58,000 0.02 0.02 3.0 examined simultaneously by the Gilcreas 21 , 21, (1938) . Old Milk 450,000 0.02 Science, and Davis and the Scharer methods for 6. Proc. Internat. Assoc. Milk Dealers, 30th 25 Control 6,500 26,000 0.02 o.oz 3.0 the purpose of control. Ten cc. of the Old Milk 340,000 0.02 Annual Convention, Lab. section, 62. control milk were inoculated with 1 cc. Note: B. I.-Before incubation 7. Scharer, Harry. Improvements in the rapid A. I.-After incubation of the culture of the test material, and phosphatase test for detection of improper Note: The bacte.riological plate counts were made by Rose Nyman Bacteriologist incubated at 37 o C. for from 4 to 5 pasteurization of milk and its products. f. ~abora.tone~, Inc.~ New York City. The phosphatase tests wer~ performed by 'the hours after which they were again sub- Milk Techtwl. 1, No. 5, 35, (1938) . m con!unctwn wrth Dr. Walter H . Eddy, Columbia University, N . Y. Remarks : . ~h1s study was begun in February, 1938. The Scharer Method employed was ongmal me_thod. The use of butyl alcohol was described later (7). Results phenol readmgs were obtamed by comparison with standards. In the zo. hour t~st, _0.2 .rercent raw and the cream again al lowed to rise. ilk in inactivated rrulk ts eastly detected. T he Scharer phosphatase test with pro­ Jll 'hosphatase which is not destroyed longed incubation is considered suitable On Phosphatase Methods in the Control of long-Time TbeJ heat treatment is concentrated in for the control of pasteurization under bye ~earn layer. . A consi~erable phos­ Danish conditions. The test of numer­ Pasteurized and Stassanized Milk. tll tase content ts found tf the cream ous samples of commercially pasteurized milk showed that a control by the phos­ Comparative Investiga~ions o~ Stein's, Kay and Graham's (1935), and Schar , phil of properly pasteurized milk is phatase test is urgently required. Methods Wtth SpeCial Regard to the Importance of Prolonging er s Jayerd A similar test is obtained on the tes~e,; layer after rhe milk has been mixed A.]. the Time of Reaction of Scharer's M~thod. ,,.,...... ' Aage Jepsen and Paul Madelung Royal V eterinary College, Copenhage1z, De11mark '', Milk designated as long-time pasteur­ ment. . ~charer'Ks method becomes nea..J. Food Control: Its Public Health Aspects ized should be held at a temperature be­ as sensttlve as ay and Gnaham's ·r t"'' tween 63 and 65 o C. for at least 30 min­ time of incubation is extended to 3 ho A New Book on the Inspection and Supervision of Food Supplies utes according to the Danish ordinances. and Scharer's method is u Milk designated as stassanized should be ior to the other two methods in u~:~:ectiD D :' To discharge their duties adequately, The comprehensive picture is of the con­ heated to at least 73 o C. in a Stassano ap· minor faults in the pasteurization if t the !food control personnel, whether gov­ trol that is now being exercised and the paratus either with a milk .film of 1.2 time of incubation is prolonged to ernlllent officials or industrial employees, control that should be exercised. mm. thickness and a time of flowing hours. need information and training in a vari­ The author's wide experience in fed­ through of at least 15 seconds, or with a Of the three methods, Scharer's is ety of field~~food technol?gy, publ~c eral and municipal food regulatory super­ milk .film of 0.6 mm. thickness and a far the easiest to conduct. health princtpl.es and pr~cttces, publtc vision, in commercial food production time of flowing through of 1.4 seconds The main result of the comparati relations, chemistry, bactenology, regula­ and its quality control, in the teaching plus 5.4 seconds in a holder. investigation are set forth in the tory procedure, quality supervision, etc. of food technology, in the organization The authors have tested the applica­ ing table: This book takes these factors into ac­ and direction of industrial control and bility of the three modifications of the 'f.he experienee with Scharer's met count in its consideration of general research laboratories, and in the foster­ phosphatase test to the control of the has been as follows: The phenol reageat principles and applications of food con­ ing of favoraole public relations, comes pasteurization in accordance with · the should be micro-crystalline and of a cl trol. Although it deals more particularly into use in all the chapters, particularly Danish ordinances. canary color. An ac;lmixtuxe of di with regulation from the public health in the expert chapters on milk produc­ 1. Stein's method published in 1937, brownish . :rystals _. iljldf<=ates a beginni tan~p oint , it also carries much material tion, milk certification, milk pasteuriza­ which is a modification of the Kay decompos1t10n whtch ts associated with on the enforcement of food standards. tion, concentrated milks, other dairy and Graham method of 1933. The reduced reacting ability. From a wide range of sources, it brings products, and canning and preserving. method is based on the liberation The amount of phenol reagent p together data on why food control is A feature which particularly recom­ of phosphorus. scribed by Scharer is. pnly sufficient (! necess ar~ what industrial practices are mends the book is the extensive up-to­ 2. Kay ana Graham's method of 1935, the development of"ift>but 50 blue uni concernea in .such control, how control date bibliography of about eight hun­ which is based on the liberation of For non-specific reasons the phenol measures are applied, and what steps dred refer.ences. It will be of consid­ phenol. liberated from phenylphospfiate if t should be taken in a food-poisoning out· erable value to thos·e using the book as a 3. Scharer's method published in 1938, samples are allowed to stand wi break. starting point ·for more extensive or in­ which is a modification of Kay and cooling and .filtration after the lead ac 'Fhe first several chapters are devoted tensive research on a specific phase of Graham's phenol method. tate precipitation. to a discussion of principles. These are the subject. The references carry the lit­ The Stein and the Scharer method with 7.5 blue units is the limit for pro followed by chapters on ·each of the erature into 1939. 1 hour incubation showed about equal pasteurization in the 20 hour test. classes of food which have been found The book reads along well. It is sensitivity in detecting faulty heat treat· blank is run on inactivated milk. to have an important bearing on public written for a wide audience and is not heafth : milk, meat, poultry, eggs, sea highly technical. An exhaustive index food, cereals, fruits and vegetables, and allows ·easy access to information that is Milk held for food preservation. Each division deals dependable, accurate, and understandable. 30 minutes at Stein Kay and Graham 1 hour systematically with the technology of the 63 co food concerned, its industrial aspects, its Food Control: Its Public Health As­ 62 .5 co relation to the public health, and the pects, by J. H. Shrader, Ph.D., John 62 co procedure commonly followed in the com­ Wiley & Sons, Inc., New York, 496 61.5 co 61 co <+> + meraial and regulatory examination of pages; 6 x 9; $4.00. 60.5 co (+) ++ n mples, and the official control practices. W. B. P. 60 co + +++ [, 256 257

Bacteriological Program of the Paper Industry The Imperial Bureau of Dairy Science The use of paper in the food industries field and to coordinate work in the fu­ In 1936 the British Commonwealth Bureau. Mr. W. G. Sutton, M.Sc., has contributed greatly to sanitary pack­ ture, the industry has recently undertaken Scientific Conference which m-et in Lon- A.I.C., from Massey Agricultural Col­ aging of foods. The demonstrated util­ a cooperative program which will con­ don to consider the working of the or- lege, New Zealand, has been appointed ity of paper in food packaging has wid­ tribute to better control of sanitation in ganizations controlled by the Executive Deputy Director and began his duties in ened its use so that at the present time manufacture of paper, establishment of Council of the Imperial Agricultural August 1938. Other m-embers of the about one-third of the fifteen million-ton sanitation standards, development of Bureaus, recommended that an Imperial staff include Miss Adelaide H. King, consumption of paper in the United methods of analysis to accompany _suGh Bureau of Dairy Science be established. B.A., Ph.D., and Miss M. M. G. Mack­ States is used for packaging food stuffs. standards, and cooperation with health The conference also suggested the Na- intosh, B.Sc. The Bureau is financed co­ During the last three or four years, agencies. This coordinated program, to tiona! Institute for Research in Dairying operatively by the Governments of the introduction of the paper milk container be administered through the American as the most suitable location for the British Empire in the same way as the has made new opportunities for use of Paper and Pulp Association, will be ex­ Bureau. other Imperial Agricultural Bureaus. paper. Believing th~t 12ape~ can. make pected to relate investigations now in Following agreement by all the author- The functions of the Bureau are to just as great a contnbut10n rn thts new progress and suggest the trend of new iti·es concerned, the new Imperial Bureau index research work in dairy science, field as it has in the -entire field of food experiments. The Association has en­ of Dairy Science ):las now been estab- whether carried out in the Empire or packaging, paper manufactur~rs ~re e~ger listed The Institute of Paper Chemistry to cooperate in every way tn mvestt~a­ to carry on the fundamental work pre­ tions on paper to be used for paper mtlk requisite to the establishment of standard containers. technics, and to expand through the use

Buildings of the lnstitllte of Paper ChemiJtry t{t Appleton, Wisconsilz

Paper manufacturers have over a long of these t-echnics the understanding of period of years undertaken programs of sanitary problems involved in the manu­ improvement in operating conditions, not facture and conversion of paper to . be Stenhouse Williams Memorial Library Buildi11gs which house the only to increase the utility of paper but used in the packaging of foods. Actt?8 Imperial Bureau of Dairy Sciet1ce also to improve its sanitary qualities. with the Institute in an advisory capac•ty These programs have been carrie~ on ~y will be Dr. Fred W. Tanner, Profess~r ~ished at Shinfield, near Reading, and elsewhere; to collect, abstract, and collate individual manufacturers, either m thetr of Bacteriology at the University of Il!•· ts housed in the Stenhouse Williams Me­ information bearing on dairy science, and own laboratories, by grants to research nois. Dr. Tanner and the Instttute wtll morial Library of the National Institute to distribute such information both by laboratories, or in cooperation with pub­ work closely with a special commi~ee for Research in Dairying (illustrated in publication and by privat-e communica­ lic and industrial agencies. comprised of experts from the p~~er JR­ figure 1). Professor H . D. Kay, O.B.E., tion to research workers, officials, and In line with this policy, to prevent un­ dustry and specially created for tl:its pur· Ph.D., D.Sc., Director of the National In­ advisory officers throughout the British necesary duplication of research in this pose by the Association. ----- stitute, has been appointed Director of the Commonwealth of Nations. In addition L )I:S IMPERIAL BUREAU JoURNAL OF MILK TECHNOLOGY 259 the Bureau is charged with the duty of Dairy Science Abstracts Standard Methods for the Examination of Dairy Products establishing and maintaining contact be­ It is announced that this new quarterly tween research workers with common This valuable manual, so necessary to Page 168, line 11. Delete last sentence abstract journal aims at providing a rec­ the milk laboratorian and sanitarian, has interests, promoting conferences of wor~­ of second paragraph reading: Trans­ ord of current research work in all fields appeared as the seventh edition of the ers and visits to research centres, and m of dairy science irrespective of the coun­ fer 10 cc. of the filtrate, taken immedi­ general encouraging the circulation of in­ former Standard Methods of Milk Analy­ ately after the filtration, into a test tube try in which it is carried out or of . the sis, published by the American Public formation, ideas, material and personnel. language in which it is published. T1tles and heat in boiling water (kept boil­ The field of dairy science to be cov­ Health Association, 50 West 50th Street, ing) for 3 minutes. Substitute: To 10 of articles will be included with full de­ New York City. It now carries 190 ered by the Bureau was defined by the tails of place of original publication, and cc. of the filtrate add 2 cc. of the pages, including a useful index-a si~e­ Conference when recommending its es­ where considered necessary, abstracts sodium carbonate solution, mix and tablishment. This field includes : the mi­ able increase over the 105 pages (no m­ written by dairy scientists. Speci~l atte?­ dex) of the last -edition. Valuable new heat in boiling water (kept boiling) crobiology, chemistry, and physics. of milk tion will be paid to papers published m for 2 minutes. and its products ; animal diseases m so far laboratory methods have been inclu~ed , journals of limited distribution and in and their interpretation has been revised Line 19. Delete last sentence of 4th as they affect milk and its products ; the less well-known languages. The sub­ in the light of the latest i nfo~~ation . paragraph reading: Heat 10 cc. of technology of processing milk and J?anu­ scription price is 25 per volume of I- This kind of work, compnsmg a labor this filtrate in a test tube in boiling facturing dairy products; the physiOlogy four numbers, post free, payable in. ~d­ of milk secretion as affecting quality and of love by numerous collaborators during water (kept boiling ) for exactly three vance with a discount of 5I- to Bnttsh "out of hours," embraces a great amount quantity of milk and dairy products; subje~ts who send their subscriptions di­ minutes. Substitute: To 10 cc. of the standards for, and methods of control of, of detailed · and critical examination of filtrate add 2 cc. of the sodium carbon­ rect to the Bureau. Each number will data rende~ed all the more difficult in the composition and quality of milk and contain an author index and each annual ate solution, mix and heat in boiling its products. The chief publication of the such' an active field as the examination of water (kept boiling) for 2 minutes. volume author and subject indexes. dairy products changing while type is be­ Bureau is a quarterly Journal, "Dairy Authors of papers will draw attention to ing set. Hence, it is to be expectc;d ~hat Page 169, line 22. Delete last sentence Science Abstracts" the first number of their work if they will send three copies of 3rd paragraph reading: Transfer 10 which has just appeared. errors will creep into such a compdatwn. of their papers to the Bureau immed_iately It is surprising that there are not more. A cc. of the .filtrate into a test tube, and The routine duties of the Bureau, such when they are available. These w1ll be place in : boiling water (kept boiling) as indexing and abstracting, will already list of those discovered thus far is pub­ catalogued and preserved as a collection lished herewith. However, some of these for 3 minutes. Substitute: To 10 cc. be familiar to many dairy workers from available for loan. items are new data, developed after the of the filtrate add 2 cc. of the sodium the activities of the Bureaus already es­ A copy of the first," issue of this excel­ carbonate solution, mix and heat in ta:blished in other subjects. An aspect o.f text was in type It would be appreciated lent abstract journal contains abstra,Clts that any errors found be reported to the boiling water (kept boiling) for 2 Bureau work which may not be so well and publication notices of 426 papers or minutes. known and understood is the more in­ publishers. reports printed on 113 pages and covers ERRATA Page 172, line 4, li.ne 7, and line 2 be­ formal service which can be given to the literature for January, February, and dairy research workers, teachers, milk san­ Page 17, 4th paragraph, line 5, shou_ld low table: It is understood in all A. March 1939. The a'!istracts are well W.iiit­ 0: A. C. reports that strengths of acid, itarians, and other field officers. The ten, easily readable, and do indeed cover read contain not delif,er. Bureau will deal directly with the indi­ Page 48, Legend for Fig. 14, interchange when not otherwise specified, are those many sources of dairy information not of the ordinary concentrated reagents. vidual workers in dairy science, who are usually encountered by the average m_ilk right and left. invited to write to the Bureau for in­ sanitarian laboratorian, and technologiSt. Legend for Fig. 15, last line, inter­ Page 174, line 2. Insert footnote: Re­ formation which is not obtainable in It is a v;luable addition to dairy litera­ change right and left. cent work indicates that a phenol value their own countries. The Bureau may ture and deserves wide support. Page 96, Line 9 of 2. Plate Method. of 0.05 mg. phenol per 0.5 cc. of sample generally indicates milk heated be able to supply the information it~lf, J. H. S. Change to read : containing crystal vio­ or to put the enquirer in touch with to 143 o F., for 30 minutes [Gilcreas, let to a final dilution of 1 :700,000. Am. J. Pub. Health, 29, 15 8 (1939) J someone who can do so more effectively. Page 115, line 29. Change to read : to Doctor Brooks Reappointed on Board Page 176. At bottom of page in table of The new Bureau of Dairy Science has pH 3.5 ± 0.1. of Medical Examiners COLOR SOLUTIONS, the values of been established in answer to requests for Page 164 line 11 Delete: to avoid the a clearing house for information in dairy Dr. Paul B. Brooks, 1st vice-president the red and yellow solutions should be later u;e of sodium carbonate. Insert: reversed: the heading given as red science, technology, and practice; its value of the International Association and dep· to avoid the formation of a pre~ipitate. should be yellow and the heading given to dairy science, and to the dairy industry uty commissioner of health of New York 'Rage 167, under Reagents insert : (c) as yellow should be red. generally will largely depend on the ex­ State, has been reappointed by the Board Sodium carbonate solution. Dissolve tent to which research workers and others of Regents of the University of the State Page 177. At top of page in table of of New York as a member of the State 140 gm. (1.32 molar solution) of pure avail themselves ·of its services. COLOR SOLUTIONS, the values Board of Medical Examiners for a term anhydrous sodium carbonate in distilled given for the blue should be red and H.D.K. of three years from August 1, 1•9!39. water and make up to 1 liter. vice versa. " JOURNAL OF MILK TECHNOLOGY Tentative Program* of the 1939 Convention Official Publication of the INTERNATIONAL ASSOCIATION OF MILK SANITARIANS, INC. International Association of Milk Sanitarians October 25-27, 1939 (Association Organized 1911) · October 25 Training of Pasteurization Plant Operators Editors Kenneth M. Renner, PALMER, MORNING, 8:30 O'CLOCK W. B. Managing Editor J. H. SHRADER, Editot' '«<.BDNESD Ay Texas Technological College, Orange, N. J, Wollaston, Mass. Lubbock, Texas. Auociate Editors gegistration Communicable Diseases Affecting Man (Com- c. A. ABELE M . A. HEINZMAN ERNEST KELLY welcome mittee Report) M. E. PARKBR. Necessity for and Some Difficulties of Public Montgomery, Ala. Ventura, Cal. Washington, D. C. Chicago, 111. Paul B. Brooks, Chait·man :Health Milk Control State Department of Health, SARAH V . DUGAN ). A. KEENAN P. F. KRUEGER G. W. PUl'NAM F. D. Brock, Albany, N. Y. Louisville, Ky. Boston, Mass. Chicago, Ill. Chicago, III. State Department of Health, October 26 ). G. HARDENBERGH c. K. jOHNS H. N. PARKER F. M. Sc.uus Austin, Texas. Plainsboro, N. J. Ottawa, Canada Jacksonville, Fla. New York, N. Y. Nuttitive Value of Milk THURSDAY MORNING, 9:30 O'CLOCK H. R. THORNTON Edmonton, Alberta, Can. Ouida Abbott, Successful Dairy Inspection University of Florida, Frank E. Kitchen, THE JOURNAL OF MILK TECHNOLOGY is is· other reading_ material should be addressed to Gainesville, Fla. Departmmt of Health, sued bimonthly beginnin~ with the January number. Editor, J. H . Shrader, Eastern Nazarene Coll lllc Each volume comprises srx numbers. It is published Wollaston, Mass. tet, The Effect of the Bang's. Di~ease C?ntrol ~~o- Greenville, S. C. by the International Association of Milk Sanitarians, graro on Milk ProductiOn m Flonda Dames Sanitary Milk Control Situation in Havana and is printed by The Chronicle Press, Inc., Orange, Membership and Dues: Active and Associate II( V. Raoul Cowley, N.J., U.S. A. ~erships in the. Association are $5.00 per year ~ · J. Knapp, . Subscriptions: The subscription rate is $3.00 per rncludes all rssue_s of the J

Connecticut Association of State Laws and the Drug and Cosmetic In­ that confront them in the various munici­ Lady Guests dustries, by }. F. Hoge, of the firm of Dairy and Milk Inspectors Rogers, Ramsey, and Hoge, New York palities. Some of these ordinances are Southern hospitality at its best will be The fall meeting of the Connecticut As­ City. on the verge of violating the Constitu­ an attraction of the Jacksonville meeting. sociation of Dairy and Milk Inspectors Standard Containers and the Consumer, by tion with respect to commerce and tax The local committee has planned special Alex Pisciotta, Director, Division of clauses. There would be no excuse for will be held on Wednesday, September Weights and Measures of the Department entertainment for the ladies. We sin­ 27, at the Hotel rBond, Hartford. The of Markets, New York City. these factors if a uniform or standardized cerely hope that as many as possible will program would be made effective through­ morning session will be held jointly with The Advantage of Standard Methods and be in attendance and lend their charm to Procedure in Dairy Products Laboratories out the United States. the Association of Dairy, Food, and Drug the occasion. In order to provide for all, by Dr. F. L. Mickle, Director, Bureau of The milk control officials of Oregon it is requested tliat tfi.ose who are bring­ Officials of the United States who are Laboratories, Connecticut State Department differ in their views from the officials in holding their annual meeting in Hart­ of Health, Hartford, Conn. ing guests with them will notify Mr. New York State, and the latter from Horatio N. Parker, Engineer Building, ford on that date. The afternoon ses­ H. C. GoSLEE, Secretary. those of California and Florida. Milk Main and Orange Streets, Jacksonville, sion will be held by the Association Metropolitan Dairy Technology Society produced under the regulations of one Florida, concerning the number of ladies alone. The first meeting of the Metropolitan Dairy town does not meet the requirements of in their parties. The program and speakers have been Technology Society for the season will be held the neighboring city ten miles away. on Tuesday evening, September 19, at 6:30 The theme of the Jacksonville meeting announced as follows: P. M. at the McGraw-Hill Building, 330 West Hotel Mayflower-Convention Headquarters. is for unity of purpose, and while no State Laws and the Food Industries, ·by Dr. 42nd St., New York City. See rates in July issue, This Jottrnal, p. 208. L. V. Burton, Editor, Food Industries. 0. F. GARRETT, Secretary-Treasurer. City of Tomo!row will be portrayed, we 0 promise palm' trees, moonlight teas, and )> The Jacksonville which welcomes the a quiet and restful climate at Jacksonville, J1 Florida. Then, too, you will have the Milk Sanitarians to their 28th Annual Jacksonville privilege of listening to and discussing Convention is a city of 155,000 inhabi­ your problems with a cosmopolitan group, tants which is located on the beautiful TwENTY-EIGHTH CoNVENTION CITY OF INTERNATIQNAL AssociATION a Pan-American group, or may we go St. Johns River eighteen miles from the OF MILK SANITARIANS further and say an international group. ocean, in the ,land of sunshine. The site On To Jacksonville The production of milk runs high as a The program calls for papers on the in pioneer days was known as the "cow In this day of progress,. we not only product of the farms ip the United States, diseases of the cow, motion pictures of ford" because here it was that the In­ drink milk, but eat it, wear it, and use and is a business wl1i"Gh runs into millions milk plants on the plateau of Mexico, dians swam their stock across the St. it for ornaments. It is used for the of dollars per annum. While tremen­ papers on milk production in the Pan­ Johns. From the city to the sea is re- _ American countries, papers on Cuba's sick, the weak, the young, and the old. dous progress has been made, it l ~nds plete with h_istorical ~ssociations for the , popular drink, a paper on the new stand­ 1 It is used not only as an article of diet itself to much further development. It; land was occupied successively by the but the products of milk are used for is a business that ~ects the farmer, the ard met ods of milk analyses, and help­ ful hints on enforcement procedures...­ Spanish, French and English, each of -1 refreshment purposes, the making of transportation company, the merchant, the whom fought fiercely for possession. St. c; banker, and every home owner. Colorful entertainment features are bread, and the propagation of poultry. Johns Bluff. and Fort George, one of the [;! It has multiple uses, and month by month The milk business, however, is rather scheduled. It is a rare opportunity to Golden Islands, are of particular histori- .-... new applications and valuable constitu­ poorly organized. Producers are han di­ visit a tropical country with its beauties ents are found by numerous investigators. capped by the complexity of ordinances and water resorts, to benefit educationally, cal significance. ?- and at the same time to mix and mingle The first family settled at the cow ford !'I with the leading authorities in the milk in 1816; others followed and the town '-­ field. was laid out in 1822; in 1832 it was in­ Write Mr. H. N. Parker, Jacksonville, corporated. The saw mill industry was requesting him to make your reservations the first to become established in a large for the dates of October 26-28, 1939. way; boat building, the naval stores, fer­ tilizer and other large businesses followed. V.M.E. In the late 90's the city became an im­ portant railroad center and flourished ac­ Members of the Entertainment cordingly. All of these are thriving and Committee besides there is an important produce P. J. LANIER, Chairman business, the largest cigar factory in the J. C. HOLLOWAY world, and there are many other success­ A. E. JOHNSON ful enterprises of various sorts. The dairy B. S. JoHNSTON industry is flourishing. All of the milk Corner of lagoon 011 Ponte Ved1·a Cotmtry Club links near Jctcksoll!lilltt WELLINGTON PAUL used in Tacksonville is nro.inrPC! in nnv~ I 400 JACKSONVILLE

County within wagon-haul of the city. The visitor who has the time to spare An inspection of these Duval County will be well repaid by trips to Jackson. dairies will give a good idea of Southern ville Beach and to St. Augustine. One dairying. who has never seen Jacksonville's match. The city has the commission form of less beach has a thrill coming. It is 60p government. It owns and operates the feet wide at low tide, smooth as a billiard electric light plant, water works and mu­ table and so firm it is used as a motor nicipal docks. The port is an important boulevard. "The Ancient City" will one for both ocean going and coastwise richly repay those who visit Old Fo.rt : traffic ; both the Clyde Line and the Marion and the Marine Studio. Those ' Merchants and Miners maintain regular planning a longer stay will find driving passenger and freight service from north­ to Miami, Tampa, Key West, and other ern ports to the city. Railroad connec­ places of interest, enjoyable and wortfi. tions to the principal cities of the country while. are excellent and the train service is of You who play golf should, by all the best. First-rate highways radiate in means, bring your equipment for Jack. all directions from Jacksonville so that sonviiie boasts some exceptionally fine those who prefer to may make the trip golf links. One of these courses is rank. to the city by bus lines or in automobiles ed by "Golf" magazine as one of t& e pleasurably. six best links in America. Here the next The city has excellent hotels and res­ Ryder Cup match will be played. taurants where accommodations and food Jacksonville welcomes you to the con. are to be had at reasonable prices. vention and to Florida.

Index to Advertisers

Aluminum Seal Company ...... XVI American Can Company ·········· -·- --·· ----·---· ···-- ·---· -,; IV Borden ·- --· --- -·- --- ·-· -···---·----·--- -··························· ·· · X Cherry-Burell Corporation ...... VI Corn Products Sales Co...... XIV Creamery Package Manufacturing Company ...... VIII Dairy Industries Supply Association ...... XIII Difco Laboratories ·················-············-----··-······- Back Cover Diversey Corporation, The ...... XVI Ford Company, The ]. B...... : ...... XII General Laboratories ...... X Johnson & Johnson ...... XV Oakite Products, Inc...... XI Pfaudler Co., The ...... v Sealright Company, Inc...... IX Sealtest, Inc ...... XVII Standard Cap and Seal Corp ...... II Tri-Clovor Machinery Co ...... XII Vitex Laboratories, Inc ...... III