Use of pesticides on conventionally grown crops is a typical practice, which helps large scale farms produce more from harvests than would naturally occur. But while food yields are abundant, there are serious health risks associated with excessive or uncontrolled use of pesticides and the ensuing exposure that can cause several health hazards including increased incidence of asthma, some types of cancers, reproductive issues. Ensuring food safety is a critical concern, and several food safety standards are set in place to strictly regulate any and all pesticide use to be certain the food we put on our table is safe to eat. Given the safety concerns, significant focus is placed on keeping pesticide use minimal by testing foods for acceptable levels of contamination and vetting those that are over regulated limits.
Regulations regarding use of pesticides and appropriate levels of accumulation in food products have become increasingly stringent in order to limit consumer exposure. Legislation in the European Union known as Directive No 752/2014, for example, sets statutory maximum residue limits (MRLs) for over 1,000 pesticides in food products of plant or animal origin. The MRLs in this directive are amongst the strictest in the world, permitting concentrations in products at levels typically as low as just several ppb.
First Things First
While stricter regulations are widely encouraged to limit pesticide accumulation in people around the globe, laboratory testing methods need to meet or exceed these demands. So, how are food safety labs supposed to test for such low levels of residue in so many foods?
Luckily, technological advancements have kept up with the growing stringency of new standards. From sample preparation to detection and quantitation, improved methods ease food safety lab pressures to ensure food is safe from farm to table.
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Sample preparation is the initial step in testing food products for pesticide residues. This normally requires homogenization of food samples and residue extraction for precise pesticide analysis. In order to simplify the process, the use of the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) methods has been widely adopted for consistent reliability. These generic extraction approaches are coupled with simple clean-up techniques to extract residues with a range of different chemical properties.
Relying on LC-MS/MS
Once residues are extracted from samples, sensitive assays help detect and quantify the smallest amounts of pesticides in order to ensure confidence in the safety of the samples tested. Liquid chromatography tandem mass spectrometry (LC-MS/MS) tends to be the technology of choice for this purpose. The selectivity, sensitivity, and speed of LC-MS/MS allows for the precise separation, detection, and quantitation of a wide variety of residue types at trace levels in a sample.
Not only does LC-MS/MS offer robust assays with high mass accuracy and precise quantitation, the inclusion of the triple quadrupole technology for mass spectrometry increases the sensitivity needed for trace detection. Complementing the enhanced technology with the use of shorter instrument dwell times and timed selection reaction monitoring, labs can now analyze hundreds of pesticides across hundreds of perishable samples efficiently and with the highest levels of analytical performance.
Ensuring the food on our plates does not contain dangerous levels of pesticides is a tall order for any lab, requiring comprehensive workflows and targeted quantitation. Advances in the methods used to extract pesticide residues from food samples as well as for analyte detection, help food safety laboratories confidently quantify these compounds beyond even the strictest current statutory limits.