Testing for Adulterated Foods

A food is illegal (adulterated) if it bears or contains an added poisonous or deleterious (harmful) substance which may render it injurious to health.This is the definition of an “Adulterated Food” that is found in Section 402(a)(1) of the Federal Food, Drug, and Cosmetic Act (FDCA). This definition encompasses not only added deleterious or unfit substances, but also pesticides, unsafe food additives, poisonous container components that may affect the food, and the intentional application of unapproved radiation.

With this definition, the Food and Drug Administration attempts to cover all the possible ways a food may be adulterated. Of course, the most insidious possibility is that a food is intentionally adulterated, especially if it is done to commit financial fraud.

FDA protects consumers from adulterated products through the use of recalls. It is important to remember that FDA has no authority under FDCA to “order” a recall, although it can request that a firm recall a product. Most recalls of products regulated by FDA are carried out voluntarily by the manufacturers or distributors of the product. In some instances, a company discovers that one of its products is defective and recalls it entirely on its own. In others, FDA informs a company of findings that one of its products is defective and suggests or requests a recall. Usually, the company will comply; if it does not, then FDA can seek a court order authorizing the federal government to seize the product.

FDA issues general information about all new recalls it is monitoring through a weekly “FDA Enforcement Report” which is available on FDA’s Web site at www.fda.gov/opacom/enforce.html.

Based on the definition of an adulterated food, there are several reasons why recalls may occur. Many recalls occur because of the presence of allergenic proteins. These are often introduced inadvertently because of cross-contamination with other processing lines. The analytical tests that detect the presence of allergenic proteins provide processors with a tool for determining whether cross-contact with an allergenic protein has occurred. These tests also are valuable in allowing manufacturers to monitor the programs that have been implemented to prevent cross-contact with allergenic proteins. Allergenic tests will undoubtedly become an integral component in a manufacturer’s program to control cross-contact with allergenic proteins.

Although tremendously valuable to the manufacturer, the allergenic test results do present potential legal and regulatory issues. The allergen test records could be discoverable in a product liability action brought against the company by a food-allergic consumer. Until a minimum threshold for allergenicity is established, any data that demonstrate the presence of an allergenic protein in a food, even if at levels below 10 ppm, could be used as evidence that a manufacturer distributed product with an undeclared allergen. These analytical tests also provide regulators with a new tool for determining the presence of undeclared allergens in the food supply. If a regulator finds an allergenic protein in the product, the company can expect the regulatory agency to request a recall.

The most common technique for the detection of allergen residues is the enzyme-linked immunosorbent assay (ELISA). Several ELISA test kits are available commercially for the detection of food allergens for raw materials, on equipment, and in finished products. Not all kits on the market are designed with detection limits appropriate for allergen residues, and various kits have differing degrees of technical expertise required for performance. ELISA testing for allergens has a definite place in HACCP plans and allergen control plans. For more information, about food allergens, see FDA’s Web site at www.cfsan.fda.gov/~dms/whalrgy.html.

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Pesticide residues on foods are another major source of recalls. FDA is responsible under FDCA for enforcing tolerances established by the Environmental Protection Agency (EPA) for amounts of pesticide residues that may legally remain on food (including animal feed). FDA collects and analyzes food from commercial channels of trade for determining compliance with EPA tolerances. Residue data gathered under this regulatory monitoring program are also used for evaluating the extent and significance of pesticide residues in the food supply. The Pesticide Analytical Manual (PAM) is published by FDA as a repository of the analytical methods used in FDA laboratories to examine food for pesticide residues for regulatory purposes (40 CFR 180.101 (c)). The manual is organized according to the scope of the analytical methods. It is available online at www.cfsan.fda.gov/~frf/pami1.html.

Most recently, bioengineered ingredients in foods have led to some widely reported recalls. One example was Star-Link corn found in manufactured taco shells. It had been approved for use in animal feed but not for use in finished food products. Such biotech ingredients are difficult to detect in the finished product. Antibody-based methods have been developed, validated, and applied to several transgenic plant products. These methods may also be used for testing grain, food ingredients, and food. However, the sampling, extraction, reference standards, and interpretation of the data may be quite different for the different applications.

These concerns also apply to the polymerase chain reaction(PCR) method, which is used to identify the DNA of the same products. Every new genetically modified product introduction makes the analytical determinations more complex. Methods are being developed to simplify the process by employing DNA arrays (biochips). These are small surfaces onto which many different DNA sequences can be immobilized and analyzed in parallel. This new technology may make testing for biotech ingredients easier.

The U.S. Dept. of Agriculture’s Grain Inspectors, Packers and Stockyards Administration (GIPSA) has established new biotech services to respond to the grain market’s need for independent sources to verify the reliability and credibility of biotech analyses for grain. They currently offer two biotechnology services to facilitate grain marketing—rapid test kits for the detection of biotechnology-derived grain, and accreditation of independent analytical laboratories that test grains for the presence of biotechnology-derived grains.

GIPSA evaluates rapid test kit technology based on the manufacturer’s claims and notifies the public of its findings. It has invited manufacturers of rapid test kit technology that determines the presence of biotechnology-derived grains in grain to submit both their test kits and supporting data. The group also evaluates and verifies the capabilities of independent laboratories using PCR testing to determine the presence of modified DNA in grain. PCR tests require a special laboratory setting and highly skilled personnel. In addition, GIPSA has established a biotech reference laboratory in Kansas City, Mo. GIPSA is working on establishing sampling guidelines for diagnostic testing for biotech grains. The largest single source of error in the analysis of grains generally is the sampling procedure. For more information on biotech grain inspection, see the GIPSA Web site at www.usda.gov/gipsa/biotech/biotech.htm.

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PRODUCTS & LITERATURE
Sample Management Software, PlateManager™ and GelManager™, provide support for DNA sample processing from registration, receipt, extraction, purification, and amplification to identification and reporting. The contents of the plate wells and gel plates are recorded and tracked throughout the entire laboratory process. Status and audit reports are available at any time. In the food industry, one possible application is for the sample tracking for the detection of genetically modified organisms. For more information, contact Zumatrix, 81 Technology Park Dr., East Falmouth, MA 02536 (phone 508-457-7911; fax 508-540-1001; www.zumatrix.com)

Viscometers and Rheometers are described in a new 2002 catalog from Brookfield Engineering Laboratories. The catalog has sections on laboratory instruments, process instruments, viscosity measurement, and accessories. The catalog is said to be easy to use and provides detailed information on the offered instruments. It also contains information on the company’s viscosity testing service, methodology consulting service on viscosity test development, and instrument calibration and certification services. A “Help me choose a viscometer” section includes a two-page pullout selection chart. For more information, contact Brookfield Engineering Laboratories, Inc., 11 Commerce Blvd., Middleboro, MA 02346-1031 (phone 800-628-8139, 508-946-6200; fax 508-946-6262; www.brookfieldengineering.com).

Abbe Refractometer provides refractive index readings in the range of 1.3000–1.7000 with a readability of 0.001 R.I. and Brix readings of 0–95% with a readability of 0.5%. The accuracy of R.I. and Brix is +/- 0.0002 and +/- 0.1%, respectively. For greater accuracy, a thermometer mounted in a metal shield is attached to the instrument and covers a temperature range of 0–50°C. Model 2WA has applications in various food processing settings for quality control and research. For more information, contact Kernco Instruments Co., Inc., 420 Kenazo Ave., El Paso, TX 79927 (phone 915-852-3375).

Temperature Measurement System for chilled and frozen foods is said to remove the need for operator skill and eliminate concerns over operator error. The system uses microwave thermal sensing technology to measure the energy transmitted, and records the temperature electronically when the product is placed in the cabinet. It is no longer necessary to rely on an operator to probe the right place in the product for the right duration and then record the correct reading. The unit also is said to overcome problems associated with the variations between surface and internal temperatures because the readings are taken across the entire product and calculated electronically. The system also takes temperature readings in a noninvasive fashion. In a production environment, the product is removed from the production line and placed into the cabinet. Readings are taken and if the results meet the temperature parameters that have been set, the product is returned to the line and allowed to continue through the production cycle. For more information, contact Loma Systems, Inc., 283 East Lies Rd., Carol Stream, IL 60188 (phone 630-681-2050; fax 630-588-1394).

Moisture Analyzer, the MB45, may be used for food processing, environmental, and quality control applications. The analyzer features an infrared halogen heating element, with a gold reflective housing, that reaches 200°C in seconds to begin uniformly drying the sample. Capable of 0.001-g readings and a 0.01–100% moisture range, it provides three preprogrammed test points for automatic test completion, allows custom-designed test end-point criteria, and has an audible signal when a test is completed. The unit lets users program and recall up to 50 drying procedures, and it has a graphical backlit display that shows percent moisture, percent solids, weight, time, temperature, and drying curve information. For more information, contact Alliance Scale, Inc., 1020 Turnpike St., Canton, MA 02021 (phone 800-343-6802; fax 781-828-9510).

by JAMES GIESE
Internet Editor