Tools For Better Food Safety Testing

Considering transportation time and test lab queues, results may not be available for a week or more. Even if a contamination event is recorded, a confirmation test is done before any action is taken. Because food processors do not “hold” inventory, a confirmed contamination results in a recall. When you couple this with the fact that only small samples are taken for examination, it is quite possible a contaminated product could elude the inspection process.

PCR Systems

Several companies have developed quicker methods, the most popular being a type of DNA testing called polymerase chain reaction (PCR) diagnostic systems. PCR systems entered the market more than 10 years ago, but in a conservative, cost-conscious industry, acceptance has been slow. According to an industry consulting firm, rapid microbial identification processes only make up about 20% of all testing done. In 2007, this represented more than 630 million tests, a growth rate of about 10% a year. PCR systems typically perform an identification in 36 to 48 hours with greater than 90% accuracy at a cost per test of about $10. Some new systems can complete the whole process in 10 hours, but the cost can be as high as $45 per test, and the capital cost can exceed $40,000.

The specific reagents or chemicals and the sample equipment needed to perform an identification are the most important drivers for test costs. A novel test method uses the principles of multi-angle laser light scattering combined with proprietary algorithms to perform an identification. The entire identification process takes less than 10 minutes, and because no chemicals or reagents are used, cost per test is about 10 cents. The capital cost of the system is significantly cheaper than the lowest priced PCR system. Although other rapid methods have a cost per test as low as $2, they are compromised in either accuracy or specificity. Table 1 (below, left) summarizes the features and costs of many of the identification test systems available today.

Independent agencies validate most rapid test methods. The AOAC Research Institute is probably the one most respected in the industry. The institute created a test protocol that rigorously tests a method for accuracy and robustness. Two different sources perform the accuracy testing. If an inconsistency in the test results occurs, either the testing is redone or a “referee” within the AOAC Research Institute, along with input from the two test sources, decides if the method should be certified.

Cost-effective, reduced-time inspection systems are highly desired, with the goal of preventing contaminated food from ever reaching the consumer. Improved food test methods will not solve all contamination problems, but they will certainly reduce the number of annual illnesses, thereby reducing healthcare costs.

Ricardi is executive vice president and COO at Micro Identification Technologies. Reach him at [email protected].