A Review on the Colorimetric Pesticide Assay Test for Safe and Sustainable Agriculture with Special Reference to Clean Food Production

Background: The World Health Organization (WHO) states that “If it is not safe, it is not food”, as it does not serve its purpose to provide proper and safe nutrition. The Food and Agriculture Organization (FAO) reiterates that Sustainable Agriculture that seeks to increase yields while limiting the need for application of pesticides or synthetic fertilizers; only can relate Food Security with Food Safety. As the second largest agrarian country of the world, India has also become one of the largest users of pesticides. Surveys have shown that Indian food is laced with one of the highest amount of toxic pesticide residues in the world. Hence, analysis of pesticide residues in food has become the governing criteria for ensuring food safety. The Food Safety and Standards Authority of India (FSSAI) have laid down science based standards towards food safety based on the Codex standards, which are the reference for the international trade in food. However, it has been found that pesticide monitoring in food is most difficult in countries where that monitoring is arguably most needed. This is because the present chromatographic techniques though can precisely determine the presence of every chemical at the minute level but the process is hugely expensive, complex, time-consuming and require specific resources and infrastructure which offer major hindrance towards regular analysis for monitoring of food safety. Especially for a country like India, with absolute dominance of marginal farmers in vegetable cultivation, lack of awareness, resource scarcity, inability to take economic risk and flaws in maintaining the standard practices w.r.t. chemical usage enhances the availability of pesticides in food product. Moreover the short time gap between the field harvest of vegetables and consumption, limits the scope for safety analysis even if the infrastructure and economics is not considered. In this background an effective, simple, and affordable method is needed to enable pesticide residue analysis in situations of limited resources more so for Safe & Sustainable Agriculture Scope & Approach: In this scenario, the Colorimetric Pesticide Assay Test can be a Real Game Changer in the Food Safety Arena and a Crucial ‘Sustainability Tool’ for Safe & Sustainable Agriculture. This test method although utilized round the globe to identify the pesticides residues both in a quantitative and qualitative manner, lack a standard protocol towards safety evaluation of vegetables in terms of detecting the presence/absence of the major pesticide groups. Another crucial point is how to measure in the most affordable and transparent manner. Then it has to be made available for small, marginal and resource poor farmers, who are more than 95% of the total farming community. Inhana Organic Research Foundation (IORF), Kolkata in collaboration with Krishi Vigyan Kendra, Nadia (ICAR) initiated a research work in June, 2020 to develop a Protocol for Colorimetric Pesticide Assay Test of vegetables with the objectives of (i) Most Authentic and Speedy Measurement of the major groups of pesticides viz. organochlorine, organophosphate, synthetic pyrethroids, carbamates and neonicotinoids, that are used during vegetable production, (ii) Identifying the collective presence/ absence of the pesticide residues up to the lowest- group specific permissible limits (same type of pesticides in terms of chemical structure) and (iii) Standardization of the Method towards its effective utilization for large scale Pesticide Residue Study in the most economical manner. The Support from IBM, India for Clean Food Production – A Safe and Sustainable Agricultural Initiative; helped in the efforts to standardize the Colorimetric Assay Test Protocol towards safety evaluation of the vegetables. The standardization process involved the analysis of more than 1200 samples of 30 major vegetables produced in India. Vegetable samples were sourced from open markets, certified organic counters and from the farmers’ field where the concept of Clean Food Program was 1st initiated by IORF in collaboration with KVK, Nadia (ICAR). Also the vegetable samples were sourced during different seasons i.e., winter (Period : November – February), monsoon (Period : July – October) and summer (Period : March – June). Key Findings & Conclusion: The newly standardized Colorimetric Pesticide Assay Test Protocol can enable detection of the collective presence/ absence of pesticides up to group specific- lowest permissible limit; for more than 90 percent of the pesticides- permitted for use in India, for most of the banned chemicals, as well as chances of residual presence in case of chemicals like DDT and its isomer. In addition; this Assay Test protocol can also be utilized for detecting the presence/ absence of toxic heavy metals such as Hg2+, Cd2+, Cu2+, Pb2+ and a wide range of other toxic substance of known/unknown origin related to human health and safety. Moreover the Colorimetric Pesticide Assay Test Protocol opens up the scope for large scale and frequent food safety analysis due to the affordable cost (1/10th to 1/15th of the Conventional Cost of Residue Analysis) and significant reduction in the analysis time (1/10th of the time required for Residue Analysis using High Performance Liquid Chromatography, HPLC).