333. The coliform flora of milk and dairy products

Abstract

233mastitis the four quarters were cited as A, B, C and D as follows: A, left front; B, right front; C, left hind; D, right hind. The simplest way to ensure that the claw was correctly applied was found to be the use of a standard position for the bucket relative to the direction in which the cow was facing. The bucket was always placed with the arrow on the lid pointed to the head of the bail, and care was taken that there was no twist in the long connecting tubes to the claw. The claw was applied to the teats with the straight tubes along instead of across the bail. With this system there was no need to alter the position of the bucket for right-and left-hand bails. It was found that there was little difficulty in using the claw as described instead of in the more usual position, transverse to the bail. Milking proceeded normally as for an ordinary bucket plant. The strip bucket was used in the same way with the arrow towards the head of the bail, so giving automatically an adjustment for right-and left-hand bails. On completion of stripping, the two buckets were placed side by side with the arrows pointing in the same direction, and the strippings were added to the corresponding quadrant container in the milking-machine bucket before weighing and sampling.The coliform organisms have probably received more attention than most other groups of non-pathogenic bacteria owing to their importance as ' indicator' species in water analysis, wherein two distinct procedures have long been employed, viz. (a) a presumptive test to demonstrate the presence or absence of coliform species in general, performed by inoculation into bile salt-lactose broth (Britain) or lactose broth (America), and (b) confirmatory tests designed to isolate and differentiate faecal from non-faecal types.Subsequently the 'coliform test' has been widely adopted in Britain for the examination of raw-milk supplies, and quantitative standards have been introduced for grading special designated raw milks. Similar tests are used extensively in pasteurized milk control, although no legal standard has been adopted. In order to facilitate examination of large numbers of samples, only the presumptive test is performed in dairy work. The validity of this procedure has been questioned by numerous workers, particularly in America, on the ground that interpretation of the test must be uncertain since faecal types are not differentiated. Conversely, it is argued that the presumptive test is sufficient since undesirable changes in milk or milk products may be produced equally by faecal and

Comparative Studies on the Detection of Pollution of Water, Milk, and Ice Cream

“…Also, the relatively higher resistance of certain groups of excretal streptococci towards pasteurisation (63 C for 30 min) than most of the coliform bacteria would seem to explain in a great part the results obtained with pasteurised milk and ice cream. Although heat-resistant coliforms are Correlation between coliformii results and excretal streptococci index in raw and pasteurized milk knoown to exist, their incidence in efficiently pasteurised milk was found to be low (Crossley, 1946;Ashton, 1950). Not all of the milk or ice cream samples which produced acid and gas in MacConkey's broth showed the presence of fecal streptococci.…”

412. Coliform bacteria in New Zealand butter

“…When anomalous results (particularly those giving MR + , VP + ) occurred, the cultures were purified by replating from a second MacConkey broth culture before being re-inoculated into the confirmatory media. The classification of coliform types, as summarized in Table 4, is similar to that used by Crossley (13), with the exception that, because of the smaller number of cultures tested, the irregular strains have not been differentiated.…”

Lait pasteurisé - Lait stérilisé. II. Aspects techniques et hygiéniques du problème des laits destinés à la consommation. Deuxième partie : Destruction des microbes de la flore banale au cours de la pasteurisation et qualité de conservation du lait pasteurisé (fin.)

“…'Si la présence de ces germes est indésirable du point de vue technique et commercial parce qu'elle limite la durée de conservation du lait, elle n'a pas, au point de vue de l',hygiène, une signification comparable à celle des bactéries pathogènes dont nous avons parlé dans la première partie (voir notamment le travail de CROSSLEY [8] au sujet des bactéries coliformes du lait). Il serait utopique, d'exiger leur absence totale et il suffit que leur nombre ne dépasse pas une certaine limite qu'il s'agit de fixer en tenant compte des indications de l'hygiène et des possibilités techniques de l'industrie laitière.…”