Test Kits for Milk and Dairy Analysis
Enzymatic bio-analysis plays an important role during the processing of milk and production of cheese, yogurt and other fermented milk beverages, such as kefir.
Milk Analysis: In the processing of milk, levels of ammonia and L-lactic acid are critical indicators of “freshness” and hygienic status. Levels of L-ascorbic acid, lactose, D-galactose, D-glucose, D-gluconic acid and urea are also routinely determined. Heat treatment of milk converts a small amount of lactose into lactulose. As this is the only source of lactulose in milk, measurement of this analyte reveals the extent of heat treatment.
Dairy Analysis: In the production of cheese, rising levels of L-lactic acid and falling levels of lactose are monitored during fermentation. In some cases, such as in manufacture of “Swiss” cheese, subsequent falling levels of L-lactic acid and rising levels of acetic acid due to the growth of propionic acid bacteria are also monitored. Levels of L-glutamic acid rise throughout the cheese production process, as a result of microbial utilisation of milk proteins. Other commonly measured analytes include citric acid, D-lactic acid, succinic acid, lactose, D-galactose, D-glucose and cholesterol.
In the production of yogurt, the conversion of lactose into D- and L-lactic acid is monitored, along with many other analytes including acetaldehyde, ammonia and ethanol. Artificial sweeteners, such as aspartame, are added to modify the final taste profile of some yogurt products.
There are many fermented milk beverages, including acidophilus milk, cultured buttermilk, sour cream and kefir. Commonly measured analytes include ethanol, that may reach 2-3%, L-lactic acid, lactose, D-galactose and D-glucose.
The accurate determination of lactose is especially important for products manufactured for the lactose intolerant.