To Market - Faster

Dairy Field, Nov 2004 by Dudlicek, Shonda Talerico

Quality-assurance equipment helps dairy processors move product more efficiently.

Spurred by growing consumer and government awareness that food safety and quality are critical public health issues, dairy processors now face more demanding pasteurization-testing regulations.

Traditional pasteurization tests, such as the Scharer Rapid Phosphatase colorimetric test, will no longer be accepted, requiring new technologies that can provide more sensitive levels of the enzyme alkaline phosphatase (ALP).

The transition is underway to find testing technologies that offer dramatically higher performance. Two options meeting the new ALP limit requirements are the Fluorophos ALP test and chemiluminescence.

The Fluorophos ALP test is offered by Advanced Instruments, Norwood, Mass.; and Weber Scientific, Hamilton, NJ.

"It's based on the same chemistry used in colorimetric tests, but involves the liberation of a chemical measured by fluorescence rather than color," says Ken Micciche, director of marketing at Advanced Instruments. "It uses an automated fluorometer and a fluorometric assay. The test is more sensitive, quicker and more reproducible than older methods. With fluorophos, the instrument interprets the results instead of a technician. This improves accuracy and dramatically reduces the evaluation process from 90 minutes to three minutes."

A properly performed Scharer test will effectively determine if a dairy product was fully pasteurized, and a major benefit is that it only costs pennies per test, says Fred Weber, president of Weber Instruments, Hamilton, N.J. "As of March 1, 2005, the Food and Drug Administration will require a pasteurization efficiency test with detection levels slightly below that of Scharer. Effectively, this can only be done with a fluorometer-based instrumentation system, such as the Fluorophos ALP test system," Weber says. "It offers very fast and precise results, but at a significantly higher cost" than the decades-old Scharer test.

Chemiluminescence uses a substrate reagent that produces a light intensity directly proportional to the amount of phosphatase enzyme in the sample. The light is scanned by an automated luminometer that interprets the results, and with a sensitivity level of 0.005 percent raw milk, the new test surpasses the accuracy of the old test.

But even with a four-minute assay sample time, a technician must run a stop solution step with each assay. Costs per test are higher than the fluorophos and a control must be run with each sample. No sample preparation is needed for fluid white milk, but a fiveminute sample preparation is necessary for other dairy products like cream, chocolate milk, cheese and yogurt. Chemiluminescence is offered by Charm Sciences, Lawrence, Mass.

The National Conference on Interstate Milk Shipments (NCIMS) approves both tests, and though there may be higher costs with the new technology, the tests offer a better indicator of pasteurization in milk. Dairy plants are able to improve HACCP programs. New testing technologies can be used to monitor and verify pasteurizer performance over time, giving plant managers an early warning and detection system to reduce unnecessary maintenance expenses, Micciche says.

Improving Analysis

Suppliers are also rolling out other testing equipment, such as milk analyzers, bacteria counting systems, metal detection and X-raying to help dairy processors streamline their quality assurance operations.

Weber Seientific's LactiCheck'" milk analyzer performs dependable multiparameter test results for fat, solids, protein, density and added water in 85 seconds and provides fast, accurate and economical results for raw or processed milks. Weber offers the single-channel LactiCheck-1, primarily calibrated for whole milk; and the dual-channel LactiCheck-2, which maintains primary calibrations for both whole and lowfat milk, testing for a wider range of milk without re-calibrating the instrument.

"Both low-maintenance models are genuinely simple to learn and operate and feature streamlined user-friendly calibrations," Weber says. "Based on established ultrasound technology, the instrument does not require any costly, caustic chemicals or reagents to run. It is compact, lightweight, totally portable and extremely reliable. LactiCheck affordability makes innovative technology a viable replacement for standard chemical analytical tests such as the Gerber or Babcock methods."

The two models have been used to analyze raw milk for cheese production at Washington State University and Roth Kase USA, Monroe, Wis.; fluid milk for standardization at Maple Row Dairy, Saranac, Mich., and Wendt's Dairy, Buffalo, N.Y.; and butterfat in a variety of products at the New Jersey State Department of Health.

"Processors are looking for the ability to easily and comprehensively document results for accurate record keeping as well as trend analysis. It can also diminish operator interpretation or error," Weber says. "In demand are instruments and systems with integrated software, or at a minimum, printed results. These features are now available in many dairy test categories including instruments for pasteurization efficiency, antibiotic residue, component assay and sanitation monitoring."