Using Quality Tools and Metrics for Comparison of Error Potential in Pathogen Testing Methods
Companies in the food industry have made significant strides in increasing the quality and safety of the food supply. The Food Safety Magazine, April/May 2012 issue notes that quality is defined differently within the food industry based on the customer. Whatever the definition used, the business of quality in the food industry must be proactive. With this in mind, the article goes on to review two programs and tools used to address quality and manage risk. These are the Hazard Analysis and Critical Control Points (HACCP) program and the Failure Mode and Effects Analysis (FMEA). A remarkable amount of focus and energy has gone into developing comprehensive HACCP plans that mitigate and control risk in order to ensure high quality standards are met within the food industry. The FMEA is now seen as an important analysis tool to be used in conjunction with the HACCP to ensure quality and brand protection.
The FMEA is done to analyze the potential for error and define mitigation strategies where that risk is identified. The importance of this tool and the need for diligent self-regulation in food testing laboratories is made more clear by an article published in the Journal of Food Safety, October 2009: Pathogen Detection in Food Microbiology Laboratories: An Analysis of Qualitative Proficiency Test Data, 1999-2007. This piece details cumulative findings from a study of proficiency test data in which labs were testing for the presence or absence of four common pathogens, Escherichia coli 0157:H7, Salmonella spp., Listeria monocytogenes and Campylobacter spp. in proficiency samples. The study reported, “The cumulative 9-year false-negative rates were 7.8% for E. coli 0157:H7, 5.9% for Salmonella spp., 7.2% for L. monocytogenes and 13.6% for Campylobacter spp…. Percentages of false-positive results were below 5.0% for all four pathogens.” The study goes on to suggest the high rate of false-negative results may be attributed to process variation, including insufficient staff training, improper temperatures and inadequate incubation times. The authors propose that the magnitude of these errors in the study may well be less than those during normal operation, testing real food samples, as testing personnel would not necessarily be treating the sample with the extra care given to those samples designated for proficiency testing.