Analysis of Organophosphate Insecticide Half-Lives in Foods Fermented with Lactic Acid Bacteria

Abstract

There is a growing concern that chronic, low-level exposure to organophosphate insecticides is a threat to human health. These synthetic chemicals are used in crop and livestock production all over the world, and the general population are exposed to them through consuming the residues that remain in food. Evidence is emerging that fermentation with lactic acid bacteria may be an effective way of reducing organophosphate insecticide residues. However, while several studies have investigated this topic, outcome measures have varied, and there has been no research to date which has consolidated this data to better understand the half-lives of organophosphate insecticides in fermented foods and the factors affecting degradation. The aim of this review was to synthesise the evidence on organophosphate insecticide degradation during lactic acid fermentation, and analyse organophosphate insecticide half-lives, in order to determine the effectiveness of lactic acid fermentation in reducing organophosphate insecticide residues in food. Furthermore, the study aimed to explore the factors that impact the rate of degradation. CAB Abstracts, Food Science and Technology Abstracts, Scopus and Web of Science were searched for eligible laboratory-based studies, which were published after 2000. The literature search and screening process resulted in the inclusion of 14 eligible studies. Studies were screened for Risk of Bias (ROB) using the RoBDMAT tool. Collated results showed that organophosphate insecticides degraded over time, and this was irrespective of fermentation. However, out of the 249 experiments that involved a controlled fermentation, 232 demonstrated that fermentation with lactic acid bacteria could speed up the degradation of organophosphate insecticides in food, beyond the rate of inherent degradation in the food matrix, leading to shorter half-lives. The half-lives of organophosphate insecticides in apple juice, milk and wheat ranged from 9.5 hours to 21 days in fermented foods and ranged from 21.4 hours to 36.5 days in non-fermented foods. Single species of lactic acid bacteria that demonstrated strong potential for organophosphate insecticide degradation were Lpb.plantarum subsp.plantarum, Lab.delbrueckii subsp.bulgaricus and Lvb. brevis, where the median percentage change in organophosphate insecticide half-life during fermentation was -42.3%, -25.0% and -22.9%, respectively. Organophosphate insecticide degradation during natural fermentation was less clear because of fewer studies and less consistent results. Whilst the collated data shows that fermentation with lactic acid bacteria is an effective method to reduce organophosphate insecticide residues in food, reflected in shorter half-lives, the small number of studies and variability among studies does limit the conclusions that can be drawn, and further research is needed to strengthen these findings. The results of our analysis may help to inform more reliable organophosphate exposure assessments for the population as well as provide novel insights for both consumers and food manufacturers, expanding the market potential for fermented foods.