Part 2 (2/2)

Various body fluids are known to possess the property of destroying bacteria and it is claimed by Fokker[19] that this same property was found in freshly drawn ated by Freudenreich,[20] and Hunziker[21] who find a sierm content takes place in milk for several hours when chilled to 40-70 F; on the other hand an actual, but usually not a marked decrease is observed for about 6 hours This pheno is known as to the cause of this apparent germicidal action The question is yet by no h the facts on which the hypothesis is based are not in controversy If such a peculiarity belongs to milk, it is not at all ierm content in the udder Freudenreich[22] found that udders which were not exarohich fact he attributed to the loss of this germicidal property

The infection of the wholethe fore milk, but it is questionable whether such rejection is worth while, except in the case of ”sanitary” dairies where erm content as possible The intrinsic loss in butter fat in the fore milk is inconsiderable as the first few streams contain only about one-fifth the normal fat content

~Infection of er drawn from the animal is immediately increased upon contact with the at air and the utensils in which the anisely upon the character of the surroundings Bacteria are so intimately associated with dirt, dust and filth of all kinds that wherever the latter are found, the former are sure to be present in abundance

The most important factors in the infection of the milk after withdrawal are the pollution which is directly traceable to the animal herself and the condition of the milk utensils Fortunately both of these sources of contareatly

~Infection directly froanisms found in milk are derived from the feed and water which the cow consu directly from the intestinal tract to the milk by the way of the blood circulation Such a view has no foundation in fact as bacteria absorbed into the circulation are practically all destroyed in the tissues by the action of the body fluids and cells[23]

While organisms cannot pass readily from the intestine to the udder, yet thisthat no attention should be given to the bacterial character of the iven should be pure and wholesome and no decomposed or spoiled food should be used

The infection traceable directly to the cow is modified materially by the conditions under which the animal is kept and the character of the feed consumed The nature of the fecal matter is in part dependent upon the character of the food The enous rations hich animals are now fed leads to the production of softer fecal discharges which is more likely to soil the coat of the animal unless care is taken The same is true with animals kept on pasture in comparison with those fed dry fodder

Stall-fed animals, however, are more likely to have their flanks fouled, unless special attention is paid to the removal of the manure All dairy stalls should be provided with a manure drop which should be cleaned as frequently as circu the bacterial conta froelatin surface The adherent bacteria developed readily in this medium, and the number of bacteria thus introduced into the milk fro colonies]

The anier to its hairy coat The nature of this coat is such as to favor the retention of these particles Unless care is taken the flanks and udder beco is displaced with every ed and finding its way into the anis cow's hairs collected with care on the elatin culture plates Almost invariably, bacteria will be found in considerable nu 9 Dirt particles are even richer in germent of hairs, epithelial scales andprocess, as at all other times, every motion of the animal is accompanied by a shower of _invisible_ particleswith bacterial life

The amount of actual impurities found in milk is often considerable and when it is remembered that about one-half of fresh manure dissolves in milk,[24] and thus does not appear as sediment, the presence of this undissolved residue bespeaks filthy conditions as toFrom actual tests made, it is computed that the city of Berlin, Germany consumes about 300 pounds of such dirt and filth daily Renk has laid down the following rule with reference to this insoluble dirt: If a sa on a transparent bottoarded as too dirty for use

While the nue, the character of the species is of even greater import Derived primarily from dirt and fecal matter, it is no wonder that such fores

~Influence of nored in deter all possible factors of infection, for when clothed in the dust-laden garments that have been worn all day, a favorable opportunity for direct conta the hands withis to be condemned Thein clean water and dried A pinch of vaseline on hands is sorasp and prevents the ready dislodgment of scales[25] It must also be borne in h the erms often remain in the syste[26] has shown that the individual erm content of milk, even where the procedure is quite the same In sanitary dairiesby machinery~ Several , soically as to their efficiency Harrison[27] has exaerm content than with hand-drawn milk The recent introduction of the Burrel-Lawrence-Kennedy machine has led to numerous tests in which very satisfactory results have been obtained If the rubber parts of the hly cleaned and kept in lime water solution, they reerreatly reduced

~Reduction in dirt and adherent bacteria~ No factor of contamination is so susceptible of improvement as that which relates to the reduction in filth and dirt which gains access during and i The care which is taken to keep the coat of the anirosser portion of such contamination, but with a dry, hairy coat, fine scales and dust particles ed[28] Ordinarily the patron thinks all evidence of such dirt is removed if the milk is strained, but this process only lessens the difficulty; it does not overcome it

Various methods are in use, the effectiveness of which is subject to considerable variation Some of these look to the elimination of the bacteria after they are once introduced into the milk; others to the prevention of infection in the first place

_1 Straining the milk_ Most of the visible, solid particles of filth, such as hairs, dirt particles, etc, can be re, the time-honored process of purification As ordinarily carried out, this process often contributes to instead of dierhly sterilized by boiling harbor anisanisested for this simple process, but the most practical and efficient strainer is that auze to which is added 3-4 layers of cheese cloth, the whole to set over the storage milk can

_2 Filtration_ In Europe especially, the systeravel and other substances has been quite extensively used These filters are built in sections and thesubstance is washed in hot water immediately after use and then steamed and finally baked While it is possible to reerreatly reduced[29] Cellulose filters have also been suggested[30] as an improvement over the sand filters Methods of filtration of this character have not been used under commercial conditions here in this country

_3 Clarification in separator_ Within recent years the custo the visible dirt by passing the al separator the crea remixed after separation This process naturally removes the solid impurities as dirt, hairs, epithelial scales and cells, also soe slierm life and the natural inference would be that the bacterial content of the reatly reduced by this procedure Eckles and Barnes[31] noted a reduction of 37 to 56 per cent

of the bacteria but others have failed to observe such reductions[32]

This condition is explained by theup of the bacterialthe that in spite of the elianic matter and bacteria, such clarified milk sours as rapidly as the untreated product[33]

The mechanical shock of separation ruptures the clusters of fat globules and so delays crea and also lessens the consistency of creaether with the increased expense of the operation and the failure to h the advantage which ely acco

_4 Washi+ng the udder_ If a surface is ed by ordinary movements Thus the air over snow-covered er the udder is applied with success to the hairy coat of the ani the animent of dust particles After these parts have been well carded to remove loose hairs and dirt particles, the skin should be thoroughly ed that this procedure lessens the yield of milk but Eckles[34] concludes from experiments that when the anie in amount of milk or butter-fat is produced

The effectiveness of thisthe actual amount of dirt and filth introduced into the erm life is shown by the instructive experiments of Fraser[35] who found that the actual aed fro process was three and one-half times as much as when the cow's udders ashed From udders visibly polluted one ounce of such filth was removed in 275 pounds of milk, while from cohose udders had been washed, the sah 24,030 pounds

Fraser observed as a result of 420 exaerm content of 4-inch culture dishes under clean but unwashed udders was 578, while under washed animals it was reduced to 192 From numerous tests erm content of the milk in the pail is increased fro period By far the larger part of this pollution can be easily prevented by cleaning and da exposed surface of pail_ The entrance of organis the area of the milk pail directly exposed to the dust shower A nuienic milk pails have been devised for this purpose In one case the pail is smaller at the top than bottom, but in most of them the common form is kept and the exposed area is lessened by h a narrower opening In some cases, strainers are also interposed so as to remove more effectually the coarse particles It is necessary to have these covers and strainers constructed in such a way so they can be easily removed and cleaned