Enhanced removal of fifteen pesticide mixture by a single bacterial strain using response surface methodology and its application in raw milk

Pesticide residues in milk and dairy products: An overview of processing degradation and trends in mitigating approaches

Milk and dairy products present considerable socioeconomic importance but are also a regular pesticide residue contamination source, which is considered a worldwide public health concern and a major international trade issue. Thus, a literature review was conducted to assess pesticide residue levels in milk and dairy products, as well as the residue degradation capacity during its processing. Organochlorine, organophosphate, synthetic pyrethroid and/or triazine were found in fluid milk, powder products, yogurts, cheese, butter, and sour cream. Thermal processing reduced most residue levels, although some treatments increased total hexachlorocyclohexane and its isomers (α-, γ-, δ-, and β-). Emerging non-thermal treatments presented promising results, but some by-products had higher toxicity than their precursors. Biodegradation by lactic acid bacteria were effective during yogurt and cheese fermentation. However, β-hexachlorocyclohexane level seems to increase in yogurts containing Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis, while increase or maintenance of pesticide residue concentration was observed during coagulation and cheese maturation. Deep research is needed to understand the isomerization and degradation mechanisms after thermal, non-thermal, and fermentation processing. Emerging heat technology can be an excellent topic to be investigated for pesticide residues degradation in the future. These mitigation approaches can be a feasible future alternative to milk and dairy production.

Microbial adaptation and impact into the pesticide's degradation

The imprudent use of agrochemicals to control agriculture and household pests is unsafe for the environment. Hence, to protect the environment and diversity of living organisms, the degradation of pesticides has received widespread attention. There are different physical, chemical, and biological methods used to remediate pesticides in contaminated sites. Compared to other methods, biological approaches and their associated techniques are more effective, less expensive and eco-friendly. Microbes secrete several enzymes that can attach pesticides, break down organic compounds, and then convert toxic substances into carbon and water. Thus, there is a lack of knowledge regarding the functional genes and genomic potential of microbial species for the removal of emerging pollutants. Here we address the knowledge gaps by highlighting systematic biology and their role in adaptation of microbial species from agricultural soils with a history of pesticide usage and profiling shifts in functional genes and microbial taxa abundance. Moreover, by co-metabolism, the microbial species fulfill their nutritional requirements and perform more efficiently than single microbial-free cells. But in an open environment, free cells of microbes are not much prominent in the degradation process due to environmental conditions, incompatibilities with mechanical equipment and difficulties associated with evenly distributing inoculum through the agroecosystem. This review highlights emerging techniques involving the removal of pesticides in a field-scale environment like immobilization, biobed, biocomposites, biochar, biofilms, and bioreactors. In these techniques, different microbial cells, enzymes, natural fibers, and strains are used for the effective biodegradation of xenobiotic pesticides.