Determining the shelf life of pasteurised milk

Soleris technology has been proven an effective indicator of the shelf life of pasteurised fluid milk, according to a study conducted by the Mississippi State University Department of Food Science, Nutrition, and Health Promotion.

When compared with the test system currently used by most dairies, Soleris' sensitive technology was more than five times faster, providing rapid, accurate test results within 38 hours, as opposed to more than 8-9 days. This allows dairies to ensure the highest quality through the shelf life of their product, increasing overall customer satisfaction.

Consumer demand for maximum freshness has driven the need for a more rapid method of to accurately test the shelf life of milk. For over 30 years, microbiological estimates have been used as the standard for measuring the shelf life of milk. Shelf life, defined as the period between processing and the time milk becomes unacceptable to consumers due to taste or odour, is adversely affected by microbial contamination. The results of the Mississippi State University study show that Soleris technology is more effective than the conventionally used Moseley Keeping-Quality test in indicating the shelf life of milk.

The Moseley test takes inherently longer to predict the shelf life of milk because it relies on a long pre-incubation, followed by a conventional plating-based system. This means that it can take 8-9 days to test a sample for microbial contamination. Soleris technology, however, features a combination of photo detection, ready-to-use assays and Windows-based software. Soleris technology rapidly and accurately determines the shelf life of milk within 38 hours.

"This rapid and accurate technology provides a more effective way for dairies to detect and troubleshoot microbial contamination present in their manufacturing operations," says Dr Ruth Eden, chief scientific officer, Centrus International. "Rapid elimination of microbial contaminants in the manufacturing process allows dairies to ensure the production of pasteurised milk with a longer shelf life while maximising customer satisfaction and decreasing product returns."

According to the American Dairy Science Association (ADSA), the most accurate way to determine milk's actual shelf life is by sensory evaluation, a test for flavour quality. The results of a sensory evaluation can be used to gauge the overall effectiveness of a microbial shelf life test system, such as the Soleris and Moseley tests.

Mississippi State University experts first determined the actual shelf life of each sample using the ADSA-approved sensory evaluation. They then ran the Moseley and Soleris tests, comparing the results with those of the sensory evaluation and then to one another.

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