Screening and identification of Lactobacillus with potential cadmium removal and its application in fruit and vegetable juices

Biodegradation of chemical contamination by lactic acid bacteria: A biological tool for food safety

Chemical pollutants such as mycotoxins and pesticides exert harmful effects on human health such as inflammation, oxidative stress, and cancer. Several strategies were applied for food decontamination, including physicochemical and biological strategies. The present review comprehensively discussed the recent efforts related to the biodegradation of eight food chemical contaminants, including mycotoxins, acrylamide, biogenic amines, N-nitrosamines, polycyclic aromatic hydrocarbons, bisphenol A, pesticides, and heavy metals by lactic acid bacteria (LAB). Biological detoxification by LAB such as Lactobacillus is a promising approach to remove the risks related to the presence of chemical and environmental pollutants in foodstuffs. It is a safe, efficient, environmentally friendly, and low-cost strategy to remove hazardous compounds. LAB can directly decrease these chemical pollutants by degradation or adsorption. Also, it can indirectly reduce the content of these pollutants by reducing their precursors. Hence, LAB can contribute to reducing chemical pollutants in contaminated foods and enhance food safety.

Heavy metals remediation through lactic acid bacteria: Current status and future prospects

With the development of industrialization and urbanization, heavy metal (HM) pollution has become an urgent problem in many countries. The use of microorganisms to control HM pollution has attracted the attention of many scholars due to its advantages of mild conditions, low process cost, and no secondary pollution. In this context, this review aimed to compile recent advances on the potential of lactic acid bacteria (LAB) as HMs biosorbents. As a food-safe class of probiotic, LAB can not only be used for HM remediation in soil and wastewater, but most importantly, can be used for metal removal in food. The extracellular adsorption and intracellular accumulation are the main mechanisms of HM removal by LAB. Lactic acid (LA) fermentation is also one of the removal mechanisms, especially in the food industry. The pH, temperature, biomass, ion concentration and adsorption time are the essential parameters to be considered during the bioremediation. Although the LAB remediation is feasible in theory and lab-scale experiments, it is limited in practical applications due to its low efficiency. Therefore, the commonly used methods to improve the adsorption efficiency of LAB, including pretreatment and mixed-cultivation, are also summarized in this review. Finally, based on the review of literature, this paper presents the emerging strategies to overcome the low adsorption capacity of LAB. This review proposes the future investigations required for this field, and provides theoretical support for the practical application of LAB bioremediation of HMs.

The transformation of heavy metal speciation during rapid high-temperature aerobic fermentation of food waste and their potential mechanisms

In this study, the content changes of multiple trace heavy metals (HMs) in food waste using a new rapid high-temperature aerobic fermentation (RTAF) technology and their relationships with different physicochemical factors were researched. The results indicated that the content of HMs in the decomposed products met the industry standards for organic fertilizers (NY/T525-2021, China). Physicochemical factors played an important role in controlling the changes in HM content. The component evolution of dissolved organic matter was studied, and its influences on the transformation of HM speciation showed that the RTAF process converted proteins into humus-like substances. Redundancy analysis revealed that the main factors driving the speciation transformation of HMs were tyrosine-like substances or microbial-derived humus (C3), molecular weight of dissolved organic matter (SUVA254) and humification degree (E250/E365). The increase in humification degree contributed to passivating HMs. The correlation network analysis results showed that the exchangeable HMs (Exc-HMs) were related to Lactobacillus and Pediococcu. Additionally, the cytoskeleton, coenzyme transport and metabolic function of microorganisms affected the Exc-HM content. These research results can provide a scientific basis for the prevention and control of HM pollution during the treatment of food waste.

Trace elements in Foodstuffs from the Mediterranean Basin-Occurrence, Risk Assessment, Regulations, and Prevention strategies: A review

Trace elements (TEs) are chemical compounds that naturally occur in the earth's crust and in living organisms at low concentrations. Anthropogenic activities can significantly increase the level of TEs in the environment and finally enter the food chain. Toxic TEs like cadmium, lead, arsenic, and mercury have no positive role in a biological system and can cause harmful effects on human health. Ingestion of contaminated food is a typical route of TEs intake by humans. Recent data about the occurrence of TEs in food available in the Mediterranean countries are considered in this review. Analytical methods are also discussed. Furthermore, a discussion of existing international agency regulations will be given. The risk associated with the dietary intake of TEs was estimated by considering consumer exposure and threshold values such as Benchmark dose lower confidence limit and provisional tolerable weekly intake established by the European Food Safety Authority and the Joint FAO/WHO Expert Committee on Food Additives, respectively. Finally, several remediation approaches to minimize TE contamination in foodstuffs were discussed including chemical, biological, biotechnological, and nanotechnological methods. The results of this study proved the occurrence of TEs contamination at high levels in vegetables and fish from some Mediterranean countries. Lead and cadmium are more abundant in foodstuffs than other toxic trace elements. Geographical variations in TE contamination of food crops clearly appear, with a greater risk in developing countries. There is still a need for the regular monitoring of these toxic element levels in food items to ensure consumer protection.

Recent advancements in cadmium-microbe interactive relations and their application for environmental remediation: a mechanistic overview

The toxic and persistent nature of cadmium (Cd) in the environment has become a matter of concern with its drastic increase in the concentrations over past few decades. Among the various techniques, the microbial remediation has been accepted as an effective decontamination tool for environmental applications, which is sustainable over a period of time. The Cd decontamination potential of the microbes depends on various internal and external factors that play a crucial role in selection of the microbes for application in a particular environment. Thus, it is important to understand the role of these factors for optimal application of the microbes. This study provides an insight into the mechanisms involved between the microbes and the environmental Cd. The study also briefly reviews the mathematical models that have been used to predict the remediation potential of the microbes and the kinetics involved during the process. A critical analysis of the recent advancements in the techniques for use of bacteria, fungi, and algal cells to remove Cd has been also presented in the manuscript.

Efficacious Removal of Trace Mercury from Honeysuckle Water Decoction Using Multifunctional Mesoporous Carbon

A mesoporous carbon (PC-2) obtained by using sucrose as a carbon source and urea as a nitrogen source has been used to remove trace mercury (Hg) from honeysuckle water decoction with high efficiency. The morphology, chemical composition, and pore structure of PC-2 have been characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET). The results show that the specific surface area of PC-2 with the -NH₂ functional is 1077.44 m²·g^-1, and the mesoporous pore size is mainly around 2.8 nm. The investigation of the relationship between the adsorption performance and the structure of PC-2 indicates that the pore size and the chemical composition of carbons are significantly correlated with adsorption performance of mercury in water and honeysuckle water decoction. PC-2 has high efficiency approximated 100% for mercury from aqueous solutions. The pseudo-second-order kinetic model and the Freundlich model could better fit the adsorption process of Hg(II) onto PC-2. The process was dominated by chemical adsorption. Meanwhile, the adsorption behavior and the influence on the medicinal components (chlorogenic acid) of mercury removal in honeysuckle water decoction were determined by high performance liquid chromatography (HPLC). Results suggest that PC-2 has high efficiency approximated 66% for mercury from honeysuckle water decoction under optimal adsorption conditions, without affecting its active ingredients (chlorogenic acid). Therefore, PC-2 can potentially be used for adsorption of mercury in honeysuckle water decoction.