MILK FLAVORS Flashcards
Cooked
This flavor results from heating milk. It may appear when all or part of the milk has been heated too high or too long. Normally, the higher the heating temperature, the more intense the cooked flavor.
Bitter
Abittertasteinfreshmilkmaybecausedby(1)strongfeedsorweedswhichmay carry through into the milk, or (2) conditions present in milk from cows in late lactation, e.g., stripper cows just before the drying-up period. Bitter taste may also result from certain bacterial growth, but normally this will not occur unless the milk is held several days at low temperatures. Bitter milk is sometimes confused with rancid milk. Remember that bitterness in only detected by taste and not by smell.
Feed
The feed a cow eats may impart certain flavors to milk. Some stronger feeds will carry through more noticeably than others. Green grass, silage, turnips, and alfalfa hay are outstanding examples. Feed flavor can be minimized or eliminated by taking the cows off offending feeds at least 4 hours before milking. Certain feeds can be detected in milk if fed to the cow even 15 to 30 minutes before milking.
Flat(watery)
The source of this uncommon flavor is difficult to determine. The flavor may be described as tasteless. The characteristic flavor or normal milk is lacking, but the milk has no off-flavor. Flat-flavored milk resembles normal milk that has been partially diluted with water, even though this may not have been done.
Foreign
Any seriously objectionable flavor foreign to milk, such as fly spray, paint, oil, kerosene, creosote, or a medicinal substance, will render the milk unpalatable or unfit for use. Such a flavor may either directly contaminate the milk or be absorbed. Sanitizes are included in this flavor category. The residue of the sanitizes, such as hypochlorite and iodophor, if left on dairy equipment, may be absorbed by milk and import a foreign flavor. Phenolic compounds used in udder ointments may combine with iodophor or hypochlorite to form a highly objectionable foreign flavor which is detectable in a very low concentration.
Garlic/Onion
The obnoxious weed flavor, imparted to milk when the cow eats garlic, onions, or leeks, is not classified as one of the usual feed flavors described above. The garlic/onion flavor is recognized by the distinctive taste and odor suggestive of its name. It may actually be so objectionable as to render the milk undesirable for use.
High Acid
Milk that has developed some acidity as a result of bacterial growth (generally Streptococcus lactis) will have a detectable acid flavor long before it may be classified as sour. Milk may have an acid flavor when only a small part of high acid milk is mixed with milk of lower acidity; yet the total acidity on the entire lot may be within normal range.
Malty
This is not a common flavor but may been countered in milk not properly cooled. Certain bacteria from improperly cleaned equipment, especially milking machines, may contaminate the milk and cause the objectionable malty flavor.
Metallic
Metallic flavor is rough and puckery on the mouth and tongue. It is caused when milk comes into contact with corrodible metal, such as exposed copper on equipment or rusty milk cans or lids. It is very objectionable and may lead to further serious defects in certain dairy products, such as butter, when held in storage. The intensity of the metallic flavor may increase in proportion to the extent of the milk’s contact with metal.
Musty
This flavor is suggestive of musty or moldy hay. It may be absorbed directly by the milk but is more likely to come from feed or stagnant water consumed by the cow.
Oxidized
Thisflavor,quitepungentinadvancedstages,isdefinitelyobjectionable.
The oxidized flavor embraces many other flavors which represent various stages of oxidation
or partial changes in the fatty portion of milk.. “Papery” or cardboard, sunlight, and tallowy
are forms of oxidized flavors with varying degrees of intensity. This is one of the most troublesome milk flavors and should be easily recognized. It develops when milk placed in a glass or plastic container is left in the sun for a short time or for a longer time under artificial light in a store cabinet. Contact with copper or iron also contributes to this flavor.
Rancid
This flavor, resembling the flavor of stale fat, is not encountered in its extreme form in fresh milk. A taste noticeable in fresh milk is sometimes referred to as “lipase” flavor, which is induced by the enzyme lipase. This enzyme causes a change in the composition of the milk fat. “Lipase” is closely associated with bitter flavor; but unlike the common bitter flavor, it has an odor resembling spoiled nut meats. It is more noticeable either during winter, when cows are on dry feed, or during late lactation. Extreme agitation of warm raw milk in the presence of air, causing foaming, will result in a rancid type flavor within a few hours.
Salty
Salty taste, which may be present in milk from cows in the late stages of lactation, is often characteristic of milk from cows infected with mastitis. It is not commonly found in herd milk or mixed milk received at a dairy plant. This defect cannot be detected by odor.
Unclean
Theuncleanflavorisseldomfoundexceptinpasteurizedmilkthathasbeenstored too long or at a slightly high refrigerator temperature. Unclean flavor often accompanies the bitter flavor. It may be caused by growth of bacteria in milk or from contact of milk with decomposed material on improperly washed or sanitized equipment or utensils.
Weedy
The weedy flavor is not included among the usual feed flavors. It generally has a bitter characteristic, varying with specific weeds of certain localities. It may include obnoxious flavors caused by such plants as ragweed, bitterweed, or peppergrass, and may become a very troublesome flavor defect. It can be eliminated or minimized by keeping cows away from weed-infested pastures or by not offering feeds containing such weeds until after the cow is milked.
