Assessment of Dairy Product Quality and Potential Shelf-Life - A Review

Abstract

Over the years, many tests and assays have been developed to estimate the quality and potential shelf-life of dairy products. These have ranged from simple, standard bacterial enumerations to more complex metabolite detections. This paper is a review of the parameters that have been used to estimate, or indicate the inherent quality of dairy products. Milk has been shown to be ideal for the growth of microorganisms due to its water, protein, carbohydrate, mineral and vitamin content, all of which are important to many forms of bacteria (62). In the days before adequate refrigeration, bacterial spoilage ran rampant, and economic losses were staggering (5). Today, farm bulk tanks, every-other-day pickup at farms, 5-d and 4-d-a-week plant operations, discontinuing of home delivery, and purchasing of milk only on shopping days have increased the age of milk before consumption (149). These methods and a more critical consuming public have caused the food industries to re-evaluate their quality standards. Quality means different things to different people and standards are ever changing. It has been pointed out that concepts of milk quality depend on many factors: (a) educational background of the individual, (b) economic and social status of the individual, (c) scientific information available, and (d) the ordinances, laws, regulations , etc., under which the dairy industry operates (62). The milk industry has been a leader in establishing programs to give the consumer a product that is pure, of good flavor, of attractive appearance and of desirable keeping quality. These programs emphasize rigorous laboratory examination of milk and dairy products to ensure that this quality is maintained (62). It is a frequently heard axiom that production of such superior quality dairy products possessing extended shelf-life requires high quality milk. Milk and other ingredients used should be free of off-odors and-flavors, abnormal chemical and physical properties, and undesirable micro-'Present address: