Effect Of Gut Microbiota On The Bioaccessibility Of Four Neonicotinoids In Apples And Pears

Pesticide residues in fruits and vegetables are the most concerned food safety issues.In terms of the bioaccessibility,the use of in vitro gastrointestinal simulation to evaluate the dietary exposure risk of pesticide residues in food has gradually become a hot topic.In this paper,four neonicotinoids in apples and pears were selected as the research objects.By comparing the effects of different in vitro methods on the bioaccessibility of pesticide residues,an in vitro gastrointestinal simulation method suitable for the determination of four neonicotinoids in apples and pears was selected.In addition,the effects of gut microbiota on the bioaccessibility of pesticide residues and the effects of major intestinal bacteria on the metabolic transformation of pesticide residues were studied.Finally,evaluation of dietary exposure risk of four neonicotinoids in apples and pears using the bioaccessibility.The results will provide a basis for evaluating the health risks of neonicotinoid insecticides in apples and pears.The main outcomes are as follows:1.Bioaccessibility of four neonicotinoids in apples and pears using the different in vitro gastrointestinal simulation methodsIn this study,we compared the differences of the bioaccessibility of four neonicotinoids using the different in vitro gastrointestinal simulation methods.Results showed that the lower and upper boundary bioaccessibility values of neonicotinoids in apples using PBET method was 56.41% and 92.17%,69.79-91.98% for SBRC,and 62.44-89.53% for IVG,respectively.Besides,results showed that the lower and upper boundary bioaccessibility values of neonicotinoids in pears using PBET method was 57.53% and 71.30%,68.69-90.85% for SBRC,and 56.91-82.08% for IVG,respectively.Based on the leaching efficiency,we select SBRC as the in vitro gastrointestinal simulation method to evaluate the bioaccessibility of neonicotinoids in apples and pears.The results showed that the bioaccessibility of four neonicotinoids in apples and pears was different using the different in vitro digestion models,which partly reflected the results of setting parameters(p H value,time,composition,etc).2.Effects of gut microbiota on the bioaccessibility of neonicotinoids in apples and pearsGut microbiota is an important factor affecting the bioaccessibility of pesticides,heavy metals and organic pollutants.In this paper,the effect of gut microbiota on the bioaccessibility of four neonicotinoids in apples and pears were studied by SBRC andSHIME in vitro gastrointestinal simulation methods.The results showed that gut microbiota significantly reduced the bioaccessibility of thiamethoxam,imidacloprid,acetamiprid and thiacloprid in apples by 22.29%,27.26%,10.22% and 17.22%,and reduced the bioaccessibility of them in pears by 7.97%,14.24%,11.22% and 18.40%,respectively.In fact,gut microbiota plays a dual role,not only promoting the dissolution and release of fungal toxins,heavy metals and persistent organic pollutants in food and soil,but also has a strong metabolic transformation capacity.It can be seen that the effect of gut microbiota on the bioaccessibility of four neonicotinoids in apples and pears are mainly hydrolysis and metabolism.3.Major intestinal bacteria affecting the bioaccessibility of neonicotinoids in apples and pearsUsing the same test method,the major intestinal bacteria that play an important role in human health were selected(Escherichia coli,Staphylococcus aureus,Lactobacillus and Bifidobacterium).The results showed that Escherichia coli reduced the bioaccessibility of imidacloprid and thiacloprid by 25.58% and 17.82% in apples,and reduced the bioaccessibility of imidacloprid and thiacloprid by 10.78% and 12.73% in pears.Staphylococcus aureus reduced the bioaccessibility of four neonicotinoids by 13.94%,9.98%,11.28% and 20.71% in apples,and reduced the bioaccessibility of three neonicotinoid insecticides(except thiamethoxam)by 15.1%,9.4% and 15.66% in pears,respectively.Lactobacillus had a degradation effect on four neonicotinoids in apples and pears,and the degradation effect in apples was better than that in pears.The degradation effect of Bifidobacterium on the four neonicotinoids in apples was not significant,only after 20 h reduced the bioaccessibility of thiacloprid and imidacloprid in pears by4.22-11.39% and 5.3-10.3%.The results showed that Lactobacillus and Staphylococcus aureus may be the major intestinal bacteria that affect the bioaccessibility of four neonicotinoids in apples and pears.4.Health risk assessment of four neonicotinoids in apples and pears based on the bioaccessibilityFor pesticide residues in food,ingestion is the most important route.This test based on the bioaccessibility of dietary intake of four neonicotinoids to evaluate their potential health risks.And the model was calculated for two subgroups,adults(general population)and children(sensitive population).Based on the hazard quotient(HQ),the dietary safety of the tested fruits were pear > apple,and the HQ value of children was higher than that of adults,indicating that children had a greater risk of dietary exposure.According to the riskassessment based on the HQ value with bioaccessibility,the levels of pesticides exposure in the tested fruits were all below the levels of health risk.