The recent news of the presence of the industrial chemical melamine in US pet food and diethylene glycol in Central American toothpaste has heightened concern over the chemical contamination of imported products. Chinese toothpaste has been linked to the deaths of 51 people in Panama last year. Pet food made with melamine, contained in mislabeled wheat flour imported from China, has been tied to the deaths of 14 pets in the US and the recall of 5,300 products.

Growing international trade in food materials has only compounded the difficulties of tracing and testing food and food-related products and ensuring their safety for consumption. According to Dr. David Acheson, the FDA’s assistant commissioner for Food Protection, in testimony before the US Congress this month, “Currently, there are over 10 million entries of imported food annually and most are large volume commercial shipments. It is estimated approximately 15% of the US food supply is imported, but for some products such as fresh fruits, imports account for 50% to 60% of the supply.”

Testing of food and food-related imports to the US, Europe and Japan has grown due to increasing global trade and new food safety legislation (see IBO 8/31/06). Chromatography and mass spectrometry are two of the analytical techniques for which demand has increased the most as a result of increased food safety concerns about organic chemical contaminants. In combination, chromatography and MS are utilized for the detection, identification and quantitation of chemical contaminants in a variety of food and food-related substances, from raw ingredients to processed products. In fact, the growth in testing of food-related products for chemical contaminants have accompanied and, in many ways, driven advancements in sample preparation, chromatography and MS. The latest food scares and the rise in imported food products from developing nations can be expected to continue to make food safety a leading market for chromatography and MS for many years to come, benefiting providers of gas chromatography (GC), liquid chromatography (LC) and most types of MS systems.

The majority of testing for chemical contaminants is done by food exporters, either in-house or by contract laboratories. Government regulators test imported food-related products, but only a small percentage of imports are tested. In the US, responsibility for food safety is divided between the USDA, which regulates meat and poultry products, and the FDA, which regulates the remainder of food products, or approximately 80% of the food supply. The FDA inspected approximately 1% of the food imports for which it is responsible, while the USDA inspected 16% of the imported food it regulated in 2006.

“The FDA is overwhelmed—they can’t do all that testing—so they have to outsource some of that testing to private contract laboratories,” said Zoe Grosser, PhD, segment marketing manager, Analytical Sciences for PerkinElmer. “For the food industry, definitely the trend is to be proactive, instead of reactive. . . . More and more, they are trying to get information upfront from the supplier and trying to run the test before getting the entire lot of materials,” said Alessandro Baldi, PhD, marketing manager, Chromatography Systems for PerkinElmer. According to James Willis, PhD, senior director of Chemical Analysis for Waters, the primary customers for food safety testing applications are the exporting countries, with testing done “either by testing labs or by government labs.” According to Dr. Willis and Dr. Baldi, the majority of food safety testing is done on finished goods as opposed to raw materials. However, for China, Dr. Baldi told IBO, ”It’s more oriented on raw material testing—that is what China is mainly exporting—than on the finished product for local usage.”

Developments in LC and MS, specifically, have driven food testing regimes for organic chemical contaminants. Analysis of chemical contaminants in food and food-related products is being conducted using GC/MS and LC/MS/MS, enabling greater sensitivity, speed and even the detection of unknown contaminants. “What we see every day when we are dealing with the food industry and contract labs that are doing food analysis [is that] they are requiring more and more mass spectrometry” said Dr. Baldi. “The reason, of course, is that mass spectrometry provides information on the identity of the molecules that they are going to analyze. Also, they are requiring a multistream of data: in other words, they want to use one or more detector,” he noted. “For gas chromatography, it’s usually one or two, or sometimes three detectors (MS being one of the detectors) to check all the different compounds.” The increased analytical capabilities have also influenced legislation. “The regulations are influenced by the analytical capabilities,” said Dr. Grosser. “We’ve seen that in environmental for years and I think that’s just becoming more clear in the food area.”

Three of the fastest growing applications for chromatography and MS analysis of organic chemical contaminants in food are testing for pesticide residues, mycotoxins and veterinary drug residues. According to Dr. Willis, pesticides are the fastest growing food safety application because of the increasing number of pesticides on the market. In a 2006 review article, Professor Yolanda Picó estimates that more than 20,000 analyses of pesticide residues in food are performed daily worldwide and states there are more than 800 types of pesticide. Multiresidue analyses are now common, in which hundred of pesticides can be screened simultaneously.

The analysis of food products uses chromatography in combination with either a single quadrupole, triple quadrupole, time-of-flight or ion trap MS system for both initial screening and subsequent confirmation. GC/MS using single quadrupole MS is most widely used for screening, while GC/MS using triple quadrupole MS is the primary confirmatory technique. GC-TOF enables screening for unknown compounds. However, LC/MS/MS techniques are the fastest growing segment of the market, according to Dr. Willis. “It used to be that most of the pesticide work was done with GC/MS, but the newer [pesticides] are more polar so they are more amenable to LC/MS/MS,” explained Dr. Willis. “So a lot of the methods are shifting from the old GCPs (Good Clinical Practices) to LC/MS/MS, which has given rise to an awful lot of growth in that business.”