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.

“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 five-minute 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.  

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 Scientific’s LactiCheck™ milk analyzer performs dependable multi-parameter 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.”

Weber says dairy processors are also interested in the company’s SpotCheck™  Plus hygiene test as a simple and effective first line of defense in allergen residue control. “This all-in-one swab device detects invisible amounts of lactose or glucose residue, a constituent of practically all foods found in a dairy processing plant,” he says. “With SpotCheck Plus you find out nearly instantly if any food residue is left on a surface, allowing corrective action to be taken on the spot.”

Boston-based Thermo Electron specializes in checkweighing, but its newest offering for the dairy industry is a metal detector that’s approved to withstand washdown, the IP69K-certified Thermo Electron DSP IP Metal Detector.

“That is targeted directly at dairy manufacturers and cheese manufacturers,” says Don Bina, Thermo’s food industry marketing communication specialist. “If you don’t have this certification, the equipment has to be covered during the washdown period. A lot of times, even when the machines are covered, they lose their sensitivity when they’re wet, so a lot of care has to be done when you’re going through the harsh washdown time during the day when you’re switching lines or periodic maintenance. This metal detector can be exposed to high-pressure and high-temperature washdowns.”

The IP69K Washdown metal detector can also do X-ray inspection and will run the full gamut of quality assurance, Bina says. “In other words, we’re the one-call stop for any type of contaminant inspection service. We’ve also come up with a new X-ray technique that is about one-third the cost of a normal X-ray. X-raying has been kind of a deterrent to a lot of processors because of the cost, so we’ve come up with a new process that has not lost any sensitivity but can detect metal and any type of contaminant at this point. It even replaces a checkweighing system,” he says.

“Say there’s a package with three or four items in it. The X-ray can tell you if there’s an item missing or a broken piece. As long as you identify an acceptable package — and we usually do that by weight — now we can do it through X-ray. You’re actually doing checkweighing and contaminant inspection at the same time and that’s pretty significant. If you’re looking at a block of cheese, you can put in the computer an acceptable weight, a rejected underweight or rejected overweight so you’re not giving away product. These are quality assurance tools that most manufacturers and most processors demand on having.”

Bentley Instruments, Chaska, Minn., has introduced its bacteria-counting systems, which count the total number of bacteria in a fluid milk sample using the flow cytometry method. The company has sold many bacteria-counting systems in Europe, and its stateside introduction made its debut at Foremost Farms, Baraboo, Wis.

Bentley’s BactoCount IBC is fully automated, and its high processing speed is ideal solution for larger laboratories that need an easy-to-maintain, exceptionally fast bacteria-counting system, analyzing 50 to 150 samples per hour, says Bent Lyder, president and owner.

The BactoCount IBC-M is a semi-automated instrument, and the rapid bacteria test is ideal for processing plants or test laboratories involved in quality assessment on milk. Analyzing time is less than one minute and sample preparation is completed in less than 10 minutes.

Lyder explains the idea behind the BactoCount systems is to isolate the bacteria by dissolving chemicals in a small milk sample so the bacteria floats in a clear fluid. The bacteria is then passed through a flow cytometer and marked with a fluorescent dye, then passed through a cytometer, where it’s hit with blue light. Bacteria then send out little red flashes every time one of them gets hit.

“They become easy to detect. Even if you pasteurize the milk and then you test the milk on our instrument, then you will get a bacteria count because we also count the dead bacteria count,” Lyder says. “It is a total bacteria count, dead or alive, because you want to know what’s on there. Even if the bacteria are dead, then it was a sign that the milk was mistreated somewhere along the line. It shows mismanagement.”

To enable customers to release their dairy products to the market faster, Celsis International offers three products exclusively for shelf-stable dairy products: the Innovate, a luminometer; Innovate.im, a software program; and RapiScreen Dairy reagents. These were created based on input from existing dairy customers and were designed to specifically meet their needs, says Roger Tye, director of global marketing in Chicago for the U.K.-based supplier.

The newest is the Innovate, a luminometer that performs rapid microbial screening to help release product to market faster.

“What would typically take four to seven days in a typical market can be reduced down to 48 hours,” Tye says. “In pasteurized milk you expect a certain amount of bacteria in there, that’s part of the process, but this is for extended shelf life, UHT dairy products, anything that should be shelf stable and sterile.”

Tye says the shelf-stable dairy product segment is moving toward rapid testing methods because it is more standardized than traditional methods like the agar plate streaking of samples and interpreting results. “It takes a less-discerning eye. You don’t have to have as much of a scientific background to run our systems,” Tye says.

This standardization enables dairy processors to better manage testing data, and this streamlining and automation is part of a larger trend, he says.

Schaumburg, Ill.-based Omron Elec­tronics offers its F210 CF date verification vision sensor, which focuses on optical character recognition and monitors printed codes for readability and rejects packages with unreadable, incomplete or missing codes. Con­currently, defects are noted so corrections can be made before large numbers of products are affected, says Jen Pulins, public relations manager.

“Savings in material waste can be substantial, and customer confidence is maintained as only clearly marked products go to market,” Pulins says. The F210 CF enables complete inspection of codes inline and the system automatically updates date codes daily without operator intervention and recognizes various date formats, including ‘manufactured on’ and ‘best before’ configurations.

“Setup and changeover is simplified and can be done through a hand-held keypad rather than a PC,” Pulins says. Extensive internal character libraries eliminate the need for teaching characters.”  df