Part 6 (1/2)

~Butyric acid fermentations~ The fornized by the ”rancid butter” odor is not infrequently seen in old, sour ht to be a continuation of the lactic feranisrowth, not so much on account of the lactic acid foren in the anisms

Most of the butyric class of bacteria are spore-bearing, and hence they are frequently present in boiled or sterilized es are quite numerous In most cases, butyric acid is proanic acids, as lactic, succinic, and acetic, are produced, likewise different alcohols Concerning the chein of butyric acid there is yet soar and casein are all decomposed by various forms In some cases, the reaction of the milk is alkaline, with other species it may be neutral or acid This type of fermentation has not received the study it deserves

In reat iain the ascendency over the lactic bacteria

~Ropy or slimy milk~ The viscosity of milk is often markedly increased over that which it normally possesses The intensity of this abnor viscous or sli threads, several feet in length, as in Fig 17 Two sets of conditions are responsible for these ropy or slimy y when drawn, as in soenerally due to the presence of viscid pus, and is often accoe, such a condition representing an inflamed state of the udder

Ropiness of this character is not usually communicable from one lot of milk to another

[Illustration: FIG 17 Ropy milk]

The communicable form of ropy milk only appears after the milk has been drawn from the udder for a day or so, and is caused by the development of various species of bacteria which find their way into the milk after it is drawn These defects are liable to occur at any season of the year Their presence in a dairy is a source of htly appearance of the h there is no evidence that these ropy fererous to health

There are undoubtedly a number of different species of bacteria that are capable of producing these viscid changes,[59] but it is quite probable that they are not of equal i milk under natural conditions

In the anism seems to be _B lactis viscosus_, a foranis at low temperatures (45-50 F), and consequently it is often able in winter to supplant the lactic-acid forerm repeatedly in water tanks where milk cans are cooled; and under these conditions it is easy to see how infection of the ht occur Marshall[62] reports an outbreak which he traced to an external infection of the udder; in another case, the slianism was abundant in the barn dust A defect of this character is often perpetuated in a dairy for soly troublesome In one instance in the writer's experience, a milk dealer lost over 150 a month for several months from ropy cream

Failure to properly sterilize cans, and particularly strainer cloths, is frequently responsible for a continuance of trouble of this sort

The slimy substance formed in milk comes from various constituents of the milk, and the chemical character of the slierms In some cases the slimy material is merely the swollen outer cell membrane of the bacteria themselves as in the case of _B lactis viscosus_; in others it is due to the decomposition of the proteids, but often the chief decomposition product appears to coar

An interesting case of a fer is seen in the use of ”lange wei” (long or stringy whey) which is eassy ferrowth of _Streptococcus Hollandicus_[63]

~Alcoholic ferar solutions are extrear does not readily undergo this change Where such changes are produced it is due to yeasts Several outbreaks attributable to such a cause have been reported[64] Russell and Hastings[65] have found these ions where Swiss cheese is made, a conditionsuch cheese

Kephir and Koumiss are liquors much used in the Orient which are one alcoholic ferinally made fro cane sugar and yeast In addition to the CO_{2} developed, alcohol, lactic acid, and casein-dissolving ferrains, which are a mass of yeast and bacterial cells The yeasts produce alcohol and CO_{2} while the bacteria change the casein of es are frequently recoest raw es produced are not yet well understood[66]

~Bitter milk~ The presence of bitter substances in milk may be ascribed to a variety of causes A nuweed and chicory, possess the property of affecting es in lactation, a bitter salty taste is occasionally to be noted that is peculiar to individual animals

A considerable number of cases of bitter in For a nuht to be associated with the butyric fermann[67] showed that the two conditions were not dependent upon each other He found that the organism which produced the bitter taste acted upon the casein

Conn[68] observed a coccus form in bitter cream that was able to impart a bitter flavor to milk Sometimes a bitter condition does not develop in the milk, but may appear later in the milk products, as in the case of a micrococcus which Freudenreich[69] found in cheese

Harrison[70] has traced a coar splitting yeast, _Torula arows rapidly in milk but produces an undesirable bitterness in cheddar cheese

Cream ripened at low te that the optimum temperature for this type of fere

Milk that has been heated often develops a bitter condition The explanation of this is that the bacteria producing the bitter substances usually possess endospores, and that while the boiling or sterilizing of er powers are not destroyed by the heat

~Soapy mann and Zirn[71]

to a specific bacillus, _B lactis saponacei_, that they found gained access to theand in another instance from hay A similar outbreak has been reported in this country,[72] due to a ger on the casein and albumen

~Red milk~ The most common trouble of this nature in milk is due to presence of blood, which is estion of certain plants as sedges and scouring rushes is also said to cause a bloody condition;matter absorbed Defects of this class can be readily distinguished frorowth because they are apparent at ti Where blood is actually present, the corpuscles settle out in a short tienic or color-producing bacteria that are able to grow in enerally they are not of much consequence Moreover their development is usually confined to the surface of the milk as it stands in a vessel The iosus_ Another for low acidity[73] is _B lactis erythrogenes_

This species only develops the red color in the dark In the light, it foranisms have been reported at different times[74]