Poked your head into a lab lately? Market and regulatory forces buffeting the dairy industry are driving immense change between milk harvesting, processing, and consuming.
Dated: 3 February 2006
BY KEN MICCICHE ADVANCED INSTRUMENTS
 The most important change agent impacting the lab is the decline in milk consumption and the rise of specialty dairy products. One of our colleagues compares milk to crude
oil. “When it was discovered during the 19th Century, oil was burned in kerosene lamps as a light source. But when electric incandescent bulbs were developed, we learned to use oil in different ways—for gasoline, jet fuel, and petrochemicals.” Milk is moving in the same direction. As consumption declines, companies are developing specialty dairy products, such as gourmet ice cream, yoghurt, and specialty drinks, which appeal to a more sophisticated consumer palette.
Dairy labs also are facing stricter government health and safety regulations. Product specifications are tighter as consumers place a higher value on taste, consistency, and appearance. Milk producers want clean, bacteria-free milk for long shelf-life. And pricing pressures, coupled with the need to meet profit expectations, make cost reduction a never-ending journey.
These business drivers are placing new and greater demands on laboratory testing procedures and analytical instrumentation. Complex product formulas require analyzers that can consistently (and continuously) decompose wide varieties of ingredients. Government proof-of-formula and bacteria count regulations require new levels of instrument accuracy. And cost reduction pressures drive demands for higher lab productivity, less equipment maintenance, and exact measurements of fat, and water content. There are four common tests that represent the bulk of the work in most cooperative, regulatory, and dairy processor laboratories. They include Cryoscopy Testing, Pasteurization Testing, Chemical Component Analysis, and Microbiological Profiling. All are in transition, as they incorporate new technology to meet tomorrow’s business demands.
Cryoscopy
When raw milk is delivered to a processing plant, a cryoscope is used to determine water content. Since milk is sold by weight, processors abhor paying for excess water. In addition, water can harbor bacteria. Present cryoscope technology is semi-automated and uses the Freezing Point depression method. Samples are tested before raw milk is unloaded into storage. Finished products also are tested for water content for quality assurance purposes. Producers judge cryoscope performance on the basis of equipment reliability, up time, and throughput.
In the future, cryoscopes could be developed to perform real-time, in-line testing, both for incoming raw milk and finished products. In-line equipment would speed up flow and reduce cost. In addition, data would be fed directly into the plant information system allowing more efficient batch validation and real-time adjustment of ingredient levels.
Pasteurization Testing
Pasteurization is one of the most important steps in processing milk and is essential for food safety. It greatly improves milk’s “keeping” quality by effectively destroying virtually all disease-producing (and most other) bacteria.
In 1990, a new Rapid Enzymatic Assay (test) was designed to confirm pasteurization. This test involved the use of an automated instrument and a fluoremetric assay. Known as Alkaline Phosphatase testing (ALP), the Fluorophos instrument interprets the results instead of a technician, dramatically reducing the evaluation process from 90 minutes to three minutes. ALP testing, unlike the colorimetric method, can be used to confirm pasteurization of many different products including bovine, sheep, and goat milk, flavored and cultured products, and cheeses.
This test is revolutionizing the way the industry checks for pasteurization. Dairy processors are enjoying higher precision and reproducibility and a ten-fold sensitivity improvement. This enhances process improvement and troubleshooting while allowing immediate process validation following maintenance. The ALP method has been accepted in Europe as a reference method and dairy producers are beginning to implement the equipment. In the US, the test’s accuracy and sensitivity resulted in the FDA lowering its pasteurization acceptance criteria from 500 to 350 mU/l of ALP activity. By lowering the criteria with better technology, plants are able to improve HACCP programs and advance the cause of food safety to protect consumers.
Component Analysis Tests
The Component Analysis Test determines the chemical makeup of milk and other dairy products. While fat content typically is the most important element tested, protein, lactose, and total solids are also frequently measured. Dairy plants use the component analysis test for proof of correct formula—a key quality assurance factor. They must be confident of producing the right formula, every time. Chemical content variability can have dramatic affect on quality and cost. For example, during ice cream manufacturing, if the fat content is not correct, the freezing temperature will change, resulting in poor product consistency. Since fat (cream) is milk’s high value component, processors keep its level as close to the minimum government requirement as possible to control cost.
Dairy labs use two types of instruments to perform these tests. The filter analyzer is a cost-effective way to test the chemical makeup of fluid milk and simple dairy products. The Fourier Transform Infrared (FTIR) analyzer can evaluate a much wider range of products, including complex recipes such as yoghurt drinks, multi-flavored ice creams, and cottage cheeses.
The filter analyzer is accurate and reliable, but cannot test a wide a variety of products. It does a great job determining the basic composition of milk and is used by hundreds of labs. In the future, these instruments will achieve higher signal-to-noise ratio providing even more accurate results.
However with the explosion in specialty dairy products, labs are moving to highly versatile FTIR technology. The FTIR analyzer, with its sensitive infrared spectrometer, is accurate enough to evaluate the most complex products and compounds. But these systems are complex and have required significant service contracts and frequent calibration. In the future, we will see instruments with higher optical and bench stability. Already, some systems are incorporating highly robust commercial benches that are built for rigorous aerospace applications. These optical systems require little maintenance and much less calibration. Tomorrow’s FTIR analyzers will be easier to use, generate higher throughput, and significantly reduce the total cost of ownership.
Microbiological Profiling
Government regulations require raw milk and finished dairy products to be tested for bacteria levels. Microbiological content has become a major concern in foods for its impact on safety, taste, and shelf life. Milk buyers will pay a premium to producers for clean milk, making bacterial content measurement a critical business issue. Currently, laboratory technicians conduct this analysis by smearing product samples on Petrifilm. Bacterial colonies are counted visually to determine the microbiological profile. This procedure is called Manual Visual Assessment. But with visual inspection, lab technicians can process only about one plate per minute—tedious, painstaking work that is highly susceptible to error.
Manual Visual Assessment can be replaced by Qcount colony counting technology. With inspection rates of up to four plates in 40 seconds, these high-throughput units can slash inspection time by more than 400%. And test results can be instantly recorded in the lab’s information system, eliminating the chance for transcription errors and maintaining virtually 100% data integrity. In addition to Qcount, Petriscan can count colonies on up to 4 Petrifilm slides simultaneously, store the data and images, while offering associated software that will allow technicians to modify system parameters to optimize system
performance and operation.
End of the Lab?
As we consider the dairy lab of the future, we see dramatic changes in the nature of its work. Testing equipment will move off the bench and onto the factory floor. Analyzers will be inserted into the production line, continuously measuring bacteria, water and chemical content on a real-time basis. This data will flow into the plant’s information and control systems, allowing realtime basis .
More Information
www.aicompanies.com
kenm@aicompanies.com.
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