Bacilli In Milk Research Articles

Mathematical Models for the Biofilm Formation of Geobacillus and Anoxybacillus on Stainless Steel Surface in Whole Milk.

Biofilm formation of Geobacillus thermodenitrificans, Geobacillus thermoglucosidans and Anoxybacillus flavithermus in milk on stainless steel were monitored at 55°C, 60°C, and 65°C for various incubation times. Although species of Geobacillus showed a rapid response and produced biofilm within 4 h on stainless steel, a delay (lag time) was observed for Anoxybacillus. A hyperbolic equation and a hyperbolic equation with lag could be used to describe the biofilm formation of Geobacillus and Anoxybacillus, respectively. The highest biofilm formation amount was obtained at 60°C for both Geobacillus and Anoxybacillus. However, the biofilm formation rates indicated that the lowest rates of formation were obtained at 60°C for Geobacillus. Moreover, biofilm formation rates of G. thermodenitrificans (1.2–1.6 Log10CFU/mL·h) were higher than G. thermoglucosidans (0.4–0.7 Log10CFU/mL·h). Although A. flavithermus had the highest formation rate values (2.7–3.6 Log10CFU/mL·h), this was attained after the lag period (4 or 5 h). This study revealed that modeling could be used to describe the biofilm formation of thermophilic bacilli in milk.

Growth of thermophilic spore forming bacilli in milk during the manufacture of low heat powders

The survival and growth of Bacillus stearothermophilus and Bacillus licheniformis, naturally present (30–300 colony forming units/ml) in late season skim milk, was monitored in a three effect evaporator during low heat skim milk powder manufacture. Substantial growth was shown to occur in the preheating stages prior to direct steam heating. A typical heat treatment (77°C, 15 s) used in the manufacture of low heat powder did not inactivate the bacteria, which continued to grow in the heater. The importance of preheaters in influencing thermophile growth in the evaporator is demonstrated by the finding that growth in the preheater stages was accompanied by growth in subsequent evaporator effects which significantly exceeded that observed when the final two preheaters were bypassed. A mid‐run mini‐clean procedure incorporating 0.2% hydrogen peroxide for decontaminating the evaporator was tested and may prove useful in extending evaporator run times

Bacilli in Milk. 2. Sweet Curd Formation

Growth characteristics, sweet curd formation, release of sialic acid, and proteolytic activity of Bacillus cereus were determined in unheated Seitz-filtered skimmilk with and without sodium hexametaphosphate.Sweet curd formation was associated with exponential growth phase of the organism and not with spore germination or sporulation. Release of the sialic acid moiety of casein from cultured skimmilk occurred at time of coagulation and when the organisms were in the vegetative state. Certain similarities in the polyacrylamide gel electrophoretic patterns of skimmilk treated with crystalline rennin and B. cereus were evident by the disappearance of κ-casein and appearance of para-κ-casein. Rate of coagulation of skimmilk but not loss of sialic acid from casein or growth of B. casein was influenced by sodium hexametaphosphate. Increased polyphosphate delayed sweet curd formation.

Bacilli in Milk. I. Spore Germination and Growth

The influence of the heat treatment of the spore and of the milk upon germination, outgrowth, and subsequent vegetative cell growth of Bacillus cereus 7 spores was determined in raw (unheated), pasteurized (62.8 C-30min), high-heated (100 C-10min), autoclaved (121 C-10min) skimmilks. Pollowing 2 hr incubation at 35C, the per cent germination for the unheated spores was 27.3, 89.7, 65.2, and 15.6, and for the heat-shocked (80 C-12min) spores it was 67.8, 99.5, 94.9, and 83.5 in raw, pasteurized, high-heated, and autoclaved skimmilks, respectively. The time required for the spores to germinate, outgrow, and initiate active cell multiplication ranged from 124min for the heat-shocked spores in pasteurized milk to 355min for the unheated spores in raw milk. When vegetative cells in exponential growth were inoculated into the various milk systems, the rate of growth for the first 30min in raw milk was approximately one-half that for pasteurized or high-heated milk. However, upon continued incubation no differences in generation time or number of generations were noted between the raw and heated milks. Heat treatment of the spore stimulated germination and subsequent outgrowth; whereas, heat treatment of the milk affected the initial rate of active cell multiplication.

The demonstration of tubercle bacilli in milk

The demonstration of tubercle bacilli in milk

BACTERIOLOGICAL ASPECTS OF IN‐BOTTLE PASTEURIZATION OF MILK, WITH A SIMPLE METHOD OF ASSESSING THE HEATING EQUIVALENT

Summary:In collaboration with the National Physical Laboratory temperature distribution in an in‐bottle pasteurization plant was studied by means of thermocouples, and the coolest point in the coolest bottles located. A simple method is given for assessing the heat‐treatment in comparison with orthodox holder pasteurization. The results of bacteriological and phosphatase activity tests of in‐bottle pasteurized milk compared very favourably with those of the holder and H.T.S.T. processes. The safety margin is similar to that of the holder process and the efficiency of destruction of tubercle bacilli in milk has been calculated to be over 100%. The heating curve follows a straight line on inverted semi‐logarithmic paper, and linear relationships are shown to exist between the ‘slope’of this line, the maximum milk temperature reached in the coolest part of the coolest bottles and the heating equivalent. It is suggested that the process can be controlled by knowing this maximum temperature.

Experiments on infection of cows with typhoid bacilli

1. A cow given by the mouth very large doses of virulent typhoid bacilli (275 and 125 thousand millions) on two occasions at an interval of 29 days failed to show signs of infection or to pass the bacilli in faeces or milk.2. Of two-month-old calves, dosed with about 100 ml. ascites broth culture of typhoid mixed with milk, one became infected and typhoid bacilli were grown from the intestine and ileocaecal gland. Both, however, passed typhoid bacilli in the faeces on the first or second day after dosing.3. When large numbers of typhoid bacilli (say, 1–3 thousand millions) were instilled into the udder through the teat canal, excretion of the bacilli in the milk usually ceased within 10 days (fourteen quarters of four cows). In two quarters of one of these cows excretion continued for 25 and 27 days, and in two quarters of another cow for at least 85 days. The procedure usually caused an acute mastitis lasting for a few days, and the ‘H’ and ‘O’ agglutinin titre of the blood rose.4. When large numbers of typhoid bacilli were applied to the teat orifice, even when this had been grossly injured beforehand by slitting the sphincter, there was as a rule only a very transient infection. In eleven cases out of twelve, either the organism could not be found in the milk or was found for 1 day only; in the remaining case there was intermittent excretion for 7 days.5. The strain of typhoid used for most of the above experiments was of high Vi content and was isolated from the carrier involved in the Bournemouth-Poole epidemic of 1936.6. These experiments do not support the view that milk-borne typhoid outbreaks are brought about by an active infection of the cow and suggest that the main object of the epidemiologist must still be the location of the human carrier.7. The chances of typhoid bacilli growing in the milk after its withdrawal from the cow are stressed.This work was rendered possible by financial assistance from the Ministry of Health and from United Dairies Limited. Thanks are due to Dr A. Felix for providing a Vi-rich culture of typhoid, and to Dr V. D. Allison for valuable help in checking the draft paper and making suggestions.

National Institute for Research in Dairying, Reading

IN the annual report for 1935 of this Institute, which has recently been issued, the research and other activities are summarized. The research work includes such varied subjects as winter feeding of young dairy cattle and artificial insemination of cows, investigations on the chemical composition of typical milk and of taints of milk, the lactic acid bacteria and cheese-ripening studies, and on pasteurization and tubercle bacilli in milk. Cases of contagious abortion among the Institute's herd of cows gave an opportunity for investigating Brucella abortus infection. Bacteriological testing of milk samples and market milk investigations have also been carried out, and the phosphatase test for efficiency of pasteurization has been re-examined. The financial condition of the Institute is considered, and an appeal is made for further funds to enable an extension of the work to be made.

Demonstration of Tubercle Bacilli in Milk by Cultural Method, by T. RUDDOCK-WEST, M.D., B.S., D.P.H., County Medical Officer of Health, Norfolk. (Member)

Demonstration of Tubercle Bacilli in Milk by Cultural Method, by T. RUDDOCK-WEST, M.D., B.S., D.P.H., County Medical Officer of Health, Norfolk. (Member)

New culture media based on sodium desoxycholate for the isolation of intestinal pathogens and for the enumeration of colon bacilli in milk and water

The Journal of Pathology and BacteriologyVolume 40, Issue 3 p. 581-599 Article New culture media based on sodium desoxycholate for the isolation of intestinal pathogens and for the enumeration of colon bacilli in milk and water Einar Leifson, Einar Leifson Department of Pathology and Bacteriology, Johns Hopkins University, BaltimoreSearch for more papers by this author Einar Leifson, Einar Leifson Department of Pathology and Bacteriology, Johns Hopkins University, BaltimoreSearch for more papers by this author First published: May 1935 https://doi.org/10.1002/path.1700400315Citations: 99AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume40, Issue3May 1935Pages 581-599 RelatedInformation

Breast infection with brucella and serum agglutination reaction

Detecting Banga bacilli in milk is very difficult, as only milk from animals can give reliable results. Therefore, it is highly advisable to develop a methodology that, while relatively simple, would allow for the accurate detection of infection of the breast, and therefore of milk. In this regard, a number of experiments have been carried out to find out the conditions under which agglutinins can occur in breast serum.

An Epidemiological Study of Diphtheria in a remote New Zealand Community

1. The incidence produced during 1926 by two epidemics of diphtheria, in a remote and unsalted country district, was equivalent to 30 years of the London endemic morbidity.2. The cases arose in two distinct groups. An autumn outbreak with a definite concentration of infection on the school age, and probably disseminated by droplet infection, followed by an epidemic in the succeeding spring which was more severe, probably milk-borne, and in which the frequency of cases was higher among infants and adults than school children.3. The effect of a long drive over bad roads caused a deterioration of the diluted toxin which was used for a Schick test investigation. The use of this toxin led at first to false conclusions regarding the immunity of the children, since it only caused reactions in the most susceptible members of the community.4. As a result of retesting with a fully potent toxin it was estimated that the figure of 40 per cent. susceptible which was found with the weak toxin would have been about 80, if full strength toxin had been used.5. The attempt to immunise actively those children who had reacted to the weak Schick toxin was found to have failed in 72 per cent. of a group which was retested 7 months later. The prophylactic course was identical with one which had succeeded in inducing Schick immunity, within 4 months, in 100 per cent. of the susceptible children in the Dunedin orphanages.6. The slow rate of immunisation at Kaitangata is attributed to two causes, (a) the low original herd immunity of the district, (b) the selection by the weak toxin of only the most sensitive reactors which were almost certainly the most “unresponsive” members of the total Schick positive population.7. By a comparison of the rate of response to a small dose of toxin-anti-toxin mixture, in those positive Schick reactors (a) who had, and (b) who had not, received previous prophylactic injections, it was shown that the principle of “primary and secondary” antigenic stimuli held good for human subjects, as well as for experimental animals.8. Careful examination of the known data led to the conclusion that the air-borne autumn epidemic had increased the herd immunity of the population, in spite of the fact that the subsequent milk-borne spring outbreak produced as high a morbidity and a more severe type of diphtheria.9. The practical lessons which may be learnt from this study are: (a) That unless a special buffered diluent is used, the toxin used for Schick testing must be freshly diluted near the place where it is to be used, (b) Active immunisation of remote unsalted communities against diphtheria requires more time, and more intensive courses of prophylactic, than areas where diphtheria has been endemic for some years, (c) In such places with a low original herd immunity, it is essential, even more than in endemic centres, never to omit retesting those who have been inoculated, in order to be certain that any attempt made to induce active immunity to diphtheria may be successful. (d) Estimations of the relative efficiency of diphtheria prophylactics, which are based on the rapidity with which samples of children become immune, are worthless unless all the observations have been made in the same environment on groups having the same original herd immunity, (e) An immunity, good enough to withstand droplet infection in a day school environment, may be broken down by massive doses of diphtheria bacilli in milk.10. The study of outbreaks of disease in communities which are not too large to prevent a complete supervision of the whole population and environment, enable one to visualise imaginary mechanisms of infection very much more easily than in large populous areas, where so many more factors have to be left unexamined, or remain unsuspected. The hypotheses, perhaps better termed surmises, which the facts suggest, are only intended to be purely tentative and temporary. Their practical value is that they indicate to the investigator a plan of campaign and suggest what to look for, in the lucky event of his ever again meeting with a similar combination of circumstances. In epidemiology in general, as illustrated by this particular instance, opportunities arise and pass, often never to recur, and much is missed, or left undone that might have been done, if only the knowledge and hints gained during the passage of the epidemic itself had been known before its advent.

The Effect of An Alternating Electric Current on Tubercle Bacilli in Milk

Journal Article The Effect of An Alternating Electric Current on Tubercle Bacilli in Milk Get access Charles M. Carpenter Charles M. Carpenter Department of Comparative Pathology and Bacteriology, New York State Veterinary College, Cornell University, Ithaca Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Infectious Diseases, Volume 44, Issue 5, May 1929, Pages 347–356, https://doi.org/10.1093/infdis/44.5.347 Published: 01 May 1929 Article history Received: 21 February 1929 Published: 01 May 1929

On the elimination of typhoid bacilli in milk

Experiments staged by V.N.Matveev and E.K. Kresling convinced them that not all races of typhoid bacilli are equally sensitive to high temperature: out of 14 cultures out of 4, when milk was heated to 75 C, 10 remained viable were killed.

An investigation into pasteurisation as a means of destroying tubercle bacilli in milk

The present unsatisfactory state of the milk supply of this country is directly responsible for a vast amount of tuberculosis among our young population. Until the universal establishment of tubercle-free herds has been adopted, pasteurisation is the best remedy we possess for this condition of affairs. The writer in a series of experiments introduced living tubercle bacilli into the “holder” of a modern pasteurising plant, during the normal daily working of the apparatus, and found in every case that such bacilli were destroyed—the test of destruction being the inability to produce tuberculous lesions in a guinea-pig. In the opinion of the writer, both the human and the bovine variety of tubercle bacilli in milk are destroyed by pasteurisation for 30 minutes at a temperature of 145–150° F. As a practical point, it is important that licensing authorities under the Milk (Special Designations) Order, 1923, should satisfy themselves that there is a minimum of frothing in the “holder” of the pasteurising apparatus.

The Colon-Aerogenes Group of Milk

Definite information concerning the significance of the colonaerogenes group of bacteria in milk is rather obscure. The characteristic gas fermentation and acid production class such organisms as undesirable in the manufacture of dairy products. Their influence, however, upon the quality of market milk is less definite. According to Harding (5), the three essential elements determining the quality of milk are--food value, healthfulness, and cleanliness. The colon-aerogenes group can effect the food value of milk only indirectly, in that through their undesirable fermentation they lessen the palatability of the commodity as a food. That the colon bacilli influence the healthfulness of milk is generally accepted, although very little direct proof is available. Such intestinal diseases as infantile diarrhoea, summer complaint and cholera infantum, commonly attributed to mill( in warm weather, have long been associated with this group. More recent investigations along this line, however, tend to make one hesitate in placing so much emphasis upon such organisms as formerly. Until more authentic data is available to the contrary, it is no doubt wise that such organisms should be considered as a suspicious source of the non-specific intestinal disorders due to milk. The colon family has long been considered of sanitary importance in milk. Numerous boards of health have adopted standards, based upon the colon content, for grading market milk. The usual assumption being that large numbers of colon indicate production under filthy conditions. Recent work, however, by Ayers, Cook and Clammer (2), indicate that large numbers of colon bacilli in milk represent growth due to holding at high temperature and not to initial contamination. The purpose of this investigation was to study the relation of the colon-aerogenes group to cleanliness of milk production.

OCCURRENCE OF TUBERCLE BACILLI IN BREAST MILK OF TUBERCULOUS WOMEN

Behring announced in 1903 that pulmonary tuberculosis could be induced from intestinal infection and that infants often become tuberculous from the milk fed to them. Since then there have been many investigations of the occurrence of tubercle bacilli in milk. The milk of tuberculous cows is of most importance in such investigations, but the milk of tuberculous women is also worthy of consideration. The demonstration of tubercle bacilli in human milk and the production of tuberculosis in animals with such milk would point out a possible means of direct transmission of the disease from mother to child. Early life is the period when individuals are most susceptible to tuberculosis, and every possible avenue of infection of children should be investigated and safeguarded if possible. The available statistics regarding the bacteriology of human milk are much less than those of cow's milk, and the literature reveals a lack of concerted conclusions.

The destruction of tubercle bacilli in milk by electricity

The destruction of tubercle bacilli in milk by electricity

The Germicidal Effect of Lactic Acid in Milk

Reference to the germicidal effect of sour milk or buttermilk on pathogenic bacteria is occasionally found in the literature. It has been intimated that lactic-acid-producing bacteria are a protection against infectiousness of contaminated milk, inasmuch as the acid produced by these bacteria is said to destroy pathogenic bacteria. There is however little positive evidence to show whether this assumption is true or not. Earlier work by Barthel,1 Bassenge,2 and Behla3 is contradictory. An investigation by Northrup4 as to the fate of typhoid bacilli in milk and in lactose broth, acidified by cultivation of lactic acid bacteria and filtered through a Chamberland filter, seems to show that acid produced by different lactic acid organisms varies in degree of germicidial action. While one strain of Bacterium lactis acidi destroyed typhoid bacilli when 0.33 percent acid (as lactic acid) was present, other strains, including the bacillus bulgaricus, had the same effect only when nearly twice as much acid was present. Krumwiede and Noble5 determined the longevity of typhoid bacilli in sour cream. The authors make the following deductions from their work:

On the Excretion of Anthrax Bacilli in Milk

On the Excretion of Anthrax Bacilli in Milk