A new insight into the adsorption mechanism of patulin by the heat-inactive lactic acid bacteria cells

Lacticaseibacillus rhamnosus encapsulated cross-linked Keratin-Chitosan hydrogel for removal of patulin from apple juice

In this study, we developed a hydrogel from cross-linked keratin and chitosan (KC) to remove patulin (PAT) from apple juice. We explored the potential of incorporating Lactobacillus rhamnoses into the KC hydrogel (KC-LR) and tested its effectiveness in removing PAT from simulated juice solutions and real apple juice. The KC hydrogel was developed through a dynamic disulfide cross-linking reaction. This cross-linked hydrogel network provided excellent stability for the probiotic cells, achieving 99.9 % immobilization efficiency. In simulated juice with 25 mg/L PAT, the KC and KC-LR hydrogels showed removal efficiencies of 85.2 % and 97.68 %, respectively, using 15 mg mL-1 of the prepared hydrogel at a temperature of 25 °C for 6 h. The KC and KC-LR hydrogels achieved 76.3 % and 83.6 % removal efficiencies in real apple juice systems, respectively. Notably, the encapsulated probiotics did not negatively impact the juice quality and demonstrated reusability for up to five cycles of the PAT removal process.

Isolation and evaluation of probiotics from traditional Chinese foods for aflatoxin B1 detoxification: Geotrichum candidum XG1 (yeast) and mechanistic insights

Identifying aflatoxin-detoxifying probiotics remains a significant challenge in mitigating the risks associated with aflatoxin contamination in crops. Biological detoxification is a popular technique that reduces mycotoxin hazards and garners consumer acceptance. Through multiple rounds of screening and validation tests, Geotrichum candidum XG1 demonstrated the ability to degrade aflatoxin B1 (AFB1) by 99-100%, exceeding the capabilities of mere adsorption mechanisms. Notably, the degradation efficiency was demonstrably influenced by the presence of copper and iron ions in the liquid medium, suggesting a potential role for proteases in the degradation process. Subsequent validation experiments with red pepper revealed an 83% reduction in AFB1 levels following fermentation with G. candidum XG1. Furthermore, mass spectrometry analysis confirmed the disruption of the AFB1 furan ring structure, leading to a subsequent reduction in its toxicity. Collectively, these findings establish G. candidum XG1 as a promising candidate for effective aflatoxin degradation, with potential applications within the food industry.

Detoxification of Mycotoxin Patulin by the Yeast Kluyveromyces marxianus YG-4 in Apple Juice

Patulin (PAT) is a mycotoxin produced by Penicillium species, which often contaminates fruit and fruit-derived products, posing a threat to human health and food safety. This work aims to investigate the detoxification of PAT by Kluyveromyces marxianus YG-4 (K. marxianus YG-4) and its application in apple juice. The results revealed that the detoxification effect of K. marxianus YG-4 on PAT includes adsorption and degradation. The adsorption binding sites were polysaccharides, proteins, and some lipids on the cell wall of K. marxianus YG-4, and the adsorption groups were hydroxyl groups, amino acid side chains, carboxyl groups, and ester groups, which were combined through strong forces (ion interactions, electrostatic interactions, and hydrogen bonding) and not easily eluted. The degradation active substance was an intracellular enzyme, and the degradation product was desoxypatulinic acid (DPA) without cytotoxicity. K. marxianus YG-4 can also effectively adsorb and degrade PAT in apple juice. The contents of organic acids and polyphenols significantly increased after detoxification, significantly improving the quality of apple juice. The detoxification ability of K. marxianus YG-4 toward PAT would be a novel approach for the elimination of PAT contamination.

Lactic acid bacteria as an eco-friendly approach in plant production: Current state and prospects

Since the late nineteenth century, the agricultural sector has experienced a tremendous increase in chemical use in response to the growing population. Consequently, the intensive and indiscriminate use of these substances caused serious damage on several levels, including threatening human health, disrupting soil microbiota, affecting wildlife ecosystems, and causing groundwater pollution. As a solution, the application of microbial-based products presents an interesting and ecological restoration tool. The use of Plant Growth-Promoting Microbes (PGPM) affected positive production, by increasing its efficiency, reducing production costs, environmental pollution, and chemical use. Among these microbial communities, lactic acid bacteria (LAB) are considered an interesting candidate to be formulated and applied as effective microbes. Indeed, these bacteria are approved by the European Food Safety Authority (EFSA) and Food and Drug Administration (FDA) as Qualified Presumption of Safety statute and Generally Recognized as Safe for various applications. To do so, this review comes as a road map for future research, which addresses the different steps included in LAB formulation as biocontrol, bioremediation, or plant growth promoting agents from the isolation process to their field application passing by the different identification methods and their various uses. The plant application methods as well as challenges limiting their use in agriculture are also discussed.

The adsorption of 2-amino-1-methyl-6-phenyl-imidazolium [4, 5-B] pyridine (PhIP) by lactic acid bacteria 37X-15 and its peptidoglycan

The heterocyclic amine 2-amino-1-methyl-6-phenyl-imidazolium [4, 5-B] pyridine (PhIP), commonly found in roasted meat products, is considered a potential carcinogen. This study is to explore the underlying mechanisms involved in the adsorption of PhIP by lactic acid bacteria 37X-15 and its peptidoglycan. The scanning electron microscope results suggested that the strain's adsorption on PhIP occurs on the cell wall, primarily composed of peptidoglycan. The fourier-transformed infrared spectroscopy results indicated that PhIP adsorption by both lactic acid bacteria 37X-15 and its peptidoglycan primarily involved OH and NH binding groups. Different adsorption conditions affected the adsorption rate of PhIP by peptidoglycan. The optimal values for each adsorption condition were 2 h, 37 °C, and pH 6 when the maximum adsorption rate reached. This study provides a new direction for the application of lactic acid bacteria and its peptidoglycan in food safety.

The effects of ultrasonic processing on the antioxidant activity of Geotrichum candidum LG-8 and its cell wall extracts

Introduction

Extraction techniques that influence cell wall polysaccharides (EPS) is crucial for maximizing their bioactivity. This study evaluates ultrasound technology for extracting antioxidant polysaccharides from Geotrichum candidum LG-8, assessing its impacton antioxidant activity.

Methods

Ultrasound extraction of EPS from G. candidum LG-8 was optimized (18 min, pH 7.0, 40 W/cm2, 0.75 M NaCl). ABTS scavenging efficiency and monosaccharide composition of LG-EPS1 and LG-EPS3 were analyzed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).

Results

The Results showed that ultrasonic treatment markedly increased the ABTS radical scavenging efficiency of LG-8 cells by 47%. At a concentration of 1 mg/mL, the ultrasonically extracted LG-EPS1 and LG-EPS3 polysaccharides exhibited significant ABTS radical scavenging efficiencies of 26% and 51%, respectively. Monosaccharide composition analysis identified mannose and glucose in LG-EPS1, while LG-EPS3 was primarily composed of mannose. FTIR spectra verified the polysaccharides' presence, and SEM provided visual confirmation of the nanoparticle structures characteristic of LG-EPS1 and LG-EPS3.

Discussion

This research not only underscores the technological merits of ultrasound in polysaccharide extraction but also highlights the potential of G. candidum LG-8 derived polysaccharides as valuable bioactive compounds for antioxidant utilization.

Cypermethrin adsorption by Lactiplantibacillus plantarum and its behavior in a simulated fecal fermentation model

The presence of cypermethrin in the environment and food poses a significant threat to human health. Lactic acid bacteria have shown promise as effective absorbents for xenobiotics and well behaved in wide range of applications. This study aimed to characterize the biosorption behavior of cypermethrin by Lactiplantibacillus plantarum RS60, focusing on cellular components, functional groups, kinetics, and isotherms. Results indicated that RS60 exopolysaccharides played a crucial role removing cypermethrin, with the cell wall and protoplast contributing 71.50% and 30.29% to the overall removal, respectively. Notably, peptidoglycans exhibited a high affinity for cypermethrin binding. The presence of various cellular surface groups including -OH, -NH, -CH3, -CH2, -CH, -P = O, and -CO was responsible for the efficient removal of pollutants. Additionally, the biosorption process demonstrated a good fit with pseudo-second-order and Langmuir-Freundlich isotherm. The biosorption of cypermethrin by L. plantarum RS60 involved complex chemical and physical interactions, as well as intraparticle diffusion and film diffusion. RS60 also effectively reduced cypermethrin residues in a fecal fermentation model, highlighting its potential in mitigating cypermethrin exposure in humans and animals. These findings provided valuable insights into the mechanisms underlying cypermethrin biosorption by lactic acid bacteria and supported the advancement of their application in environmental and health-related contexts. KEY POINTS: • Cypermethrin adsorption by L. plantarum was clarified. • Cell wall and protoplast showed cypermethrin binding ability. • L. plantarum can reduce cypermethrin in a fecal fermentation model.

Brazilian Table Olives: A Source of Lactic Acid Bacteria with Antimycotoxigenic and Antifungal Activity

Food and feed contamination by fungi, especially by toxigenic ones, is a global concern because it can pose serious health problems when the production of mycotoxins is involved. Lactic acid bacteria (LAB), well-known for fermenting foods, have been gaining attention for their antifungal and anti-mycotoxin properties. This work tested 14 LAB strains isolated from naturally fermented Brazilian table olives for growth inhibition of Aspergillus flavus, Aspergillus carbonarius, Penicillium nordicum, and Penicillium expansum. The strains Lacticaseibacillus paracasei subsp. paracasei CCMA 1764, Levilactobacillus brevis CCMA 1762, and Lactiplantibacillus pentosus CCMA 1768 showed the strongest antifungal activity, being more active against P. expansum. Aflatoxin B1 (AFB1), ochratoxin A (OTA), and patulin (PAT) production was reduced essentially by mycelia growth inhibition. The main organic acids detected in the cell free supernatant (CFS) were lactic and acetic acids. Tested LAB exhibited adsorption capacity against AFB1 (48-51%), OTA (28-33%), and PAT (23-24%). AFB1 was converted into aflatoxin B2a (AFB2a) by lactic and acetic acids produced by the strain CCMA 1764. A similar conversion was observed in solutions of these organic acids (0.1 M). These findings demonstrate the potential of isolated LAB strains as natural agents to control toxigenic fungi and their mycotoxins in fermented products, such as table olives.

Stemness potency and structural characteristics of thyroid cancer cell lines

BACKGROUND

Thyroid cancer is the most frequent type of endocrine malignancy. Thyroid carcinomas are derived from the follicular epithelium and classified as papillary (PTC) (85%), follicular (FTC) (12%), and anaplastic (ATC) (<3%). Thyroid cancer could arise from thyroid cancer stem-like cells (CSCs). CSCs are cancer cells that feature stem-like properties. Kruppel-like factor (KLF4) and Stage-spesific embryonic antigen 1 (SSEA-1) are types of stem cell markers. Filamentous actin (F-actin) is an essential part of the cellular cytoskeleton. The purpose of this study was to evaluate the stem cell potency and the spatial distribution of the cytoskeletal element F-actin in PTC, FTC, and ATC cell lines.

MATERIALS AND METHODS

Normal thyroid cell line (NTC) Nthy-ori-3-1, PTC cell line BCPAP, FTC cell line FTC-133 and ATC cell line 8505c were stained with SSEA-1 and KLF4 for stem cell potency and F-actin for cytoskeleton. The morphological properties of cells were assessed by a scanning electron microscope (SEM) and elemental ratios were compared with EDS.

RESULTS

PTCs had greater percentages of SSEA-1 and KLF4 protein intensity (0.32% and 0.49%, respectively) than NTCs. ATCs had a greater proportion of KLF4 expression (0.8%) than NTCs. NTCs and FTCs had increased F-actin intensity across the cell, but PTCs had the lowest among these four cell lines. NTCs and PTCs, as well as NTCs and FTCs, have statistically identical aspect ratios and round values. These values, however, were statistically different in ATCs.

CONCLUSION

The study of stem cell markers and the cytoskeletal element F-actin in cancer and normal thyroid cell lines may assist in the identification of new therapeutic targets and contribute in the understanding of treatment resistance mechanisms.

Optimization and adsorption characteristics of beads based on heat-inactivated bacterial biomaterial towards the pesticide Cypermethrin

AIMS

Beads containing heat-inactivated bacterial biomaterial (BBBs) were prepared for removal of cypermethrin (CPM) and the conditions for this removal were evaluated and optimized via single-factor coupled orthogonal experiments based on five factors. The adsorption characteristics of BBBs and the binding mechanism were then explored.

METHODS AND RESULTS

Results showed that the adsorption rate of CPM could reach 98% with beads prepared under optimized conditions: equal volumes of Lactobacillus cell debris derived from 1×1011 CFU; 2% hydroxypropyl-β-cyclodextrin and 2.5% activated carbon concentration, were mixed to give mixture TM, and this and SA, was mixed 1:4 with sodium alginate (SA) and beads were prepared using a 26-Gauge needle). The best adsorption conditions were initial CPM concentration of 10 mg l-1, incubation time of 24 h, and rotational speed of 180 rpm. BBBs have a well-formed structure and abundant surface functional groups, such as -COOH, -OH, -NH, -CH, -CO, -C=C. The adsorption process conformed to pseudo-second-order kinetic, and it was also a Freundlich monolayer adsorption, and the calculated maximum adsorption capacity was 9.69 mg g-1 under optimized conditions.

CONCLUSIONS

BBBs showed the highest CPM removal capacity and a good tolerance ability.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results provided a theoretical foundation for developing an adsorbent with heat-inactivated Lactobacillus plantarum (L. plantarum) RS60 for removing CPM in wastewater or drinks.

Acrylamide adsorption by Enterococcus durans and Enterococcus faecalis: In vitro optimization, simulated digestive system and binding mechanism

Acrylamide is an unsaturated amide that forms in heated, starchy food products. This study was conducted to (1) examine the ability of 38 LAB to remove acrylamide; (2) optimize acrylamide removal of selected LAB under various conditions (pH, temperature, time and salt) using the Box–Behnken design (BBD); (3) the behavior of the selected LAB under the simulated gastrointestinal conditions; and (4) investigate the mechanism of adsorption. Out of the 38 LAB, Enterococcus durans and Enterococcus faecalis had the highest results in removing acrylamide, with 33 and 30% removal, respectively. Those two LAB were further examined for their binding abilities under optimized conditions of pH (4.5–6.5), temperature (32°C - 42°C), time (14–22 h), and NaCl (0–3% w/v) using BBD. pH was the main factor influenced the acrylamide removal compared to other factors. E. durans and E. faecalis exhibited acrylamide removal of 44 and 53%, respectively, after the in vitro digestion. Zeta potential results indicated that the changes in the charges were not the main cause of acrylamide removal. Transmission electron microscopes (TEM) results indicated that the cell walls of the bacteria increased when cultured in media supplemented with acrylamide.

Factors Influencing the Bioavailability of Organic Molecules to Bacterial Cells-A Mini-Review

The bioavailability of organic compounds to bacterial cells is crucial for their vital activities. This includes both compounds that are desirable to the cells (e.g., sources of energy, carbon, nitrogen, and other nutrients) and undesirable compounds that are toxic to the cells. For this reason, bioavailability is an issue of great importance in many areas of human activity that are related to bacteria, e.g., biotechnological production, bioremediation of organic pollutants, and the use of antibiotics. This article proposes a classification of factors determining bioavailability, dividing them into factors at the physicochemical level (i.e., those related to the solubility of a chemical compound and its transport in aqueous solution) and factors at the microbiological level (i.e., those related to adsorption on the cell surface and those related to transport into the cell). Awareness of the importance of and the mechanisms governing each of the factors described allows their use to change bioavailability in the desired direction.

The importance and mitigation of mycotoxins and plant toxins in Southeast Asian fermented foods

Fermented foods (ffs) and beverages are widely consumed in Southeast Asia (SEA) for their nutritional balance, flavor, and food security. They serve as vehicles for beneficial microorganisms performing a significant role in human health. However, there are still major challenges concerning the safety of ffs and beverages due to the presence of natural toxins. In this review, the common toxins found in traditional ffs in SEA are discussed with special reference to mycotoxins and plant toxins. Also, mitigation measures for preventing risks associated with their consumption are outlined. Ochratoxin, citrinin, aflatoxins were reported to be major mycotoxins present in SEA ffs. In addition, soybean-based ff food products were more vulnerable to mycotoxin contaminations. Common plant toxins recorded in ffs include cyanogenic glycosides, oxalates, phytates and saponins. Combined management strategies such as pre-harvest, harvest and post-harvest control and decontamination, through the integration of different control methods such as the use of clean seeds, biological control methods, fermentation, appropriate packaging systems, and controlled processing conditions are needed for the safe consumption of indigenous ffs in SEA.

Potential probiotic strains with heavy metals and mycotoxins bioremoval capacity for application in foodstuffs

Heavy metals and mycotoxins in foodstuffs are one of the major concerns of our world nowadays. Food decontamination with the help of microbial biomass is a cheap, easy, efficient, and green method known as bioremoval. Probiotics are able to reduce the availability of heavy metals and toxins in food products. The purpose of this review is to summarize the probiotics and potential probiotics' interesting role in food bio-decontamination. After a brief glance at the definition of potential probiotic strains with bioremoval ability, LABs (lactic acid bacteria) are described as they are the most important groups of probiotics. After that, the role of the main probiotic and potential probiotic strains (Bacillus, Lactobacillus, Lactococcus, Enterococcus, Bifidobacterium, Pediococcus, Propionibacterium, Streptococcus, and Saccharomyces cerevisiae) for heavy metals and mycotoxins bioremoval are described. Additionally, the bioremoval mechanism and the effect of some factors in bioremoval efficiency are explained. Finally, the investigations about probiotic and contaminant stability are mentioned. It is worth mentioning that this review article can be exerted in different food and beverage industries to eliminate the heavy metals and mycotoxins in foodstuffs.

Reduction the contamination of patulin during the brewing of apple cider and its characteristics

Patulin is one of the most significant food safety problems in fruit and derived products. The reduction of patulin contamination in food processing has always been the focus of research. In this study, nine yeast strains were applied for the brewing of apple cider and the fate of patulin was determined. In this process, the patulin contamination can be decreased by adsorption onto and degradation of yeast cells in the main fermentation (20.8-49.1%), as well as the adsorption removal during clarification (18.7-58%), inverted cans (21.3-31.4%) and aging (1.0-5.8%). Saccharomyces cerevisiae (1027) was selected to reveal the elimination mechanism of patulin in main fermentation. The decrease of patulin content was mainly due to degradation and the intracellular enzymes played a more important role than extracellular ones. In addition, the synthesis of enzymes was related to the induction of patulin. Furthermore, the degradation product of patulin in the main fermentation was identified as E-ascladiol, which is less toxic than patulin. Based on the representative strain of S. cerevisiae 1027, patulin contamination can be effectively eliminated during apple cider brewing. This study provides a new insight into eliminating patulin contamination in the brewing of apple cider.

Adsorption Behavior of 3-phenoxybenzoic Acid by Lactobacillus Plantarum and Its Potential Application in Simulated Digestive Juices

3-PBA is a major degradation intermediate of pyrethroids. Its widespread existence in the environment poses a severe threat to the ecosystem and human health. This study evaluated the adsorption capacity of L. plantarum RS20 toward 3-PBA. Batch adsorption experiments indicated that the optimal adsorption conditions were a temperature of 37 °C and initial pH of 6.0–8.0, under which the removal rate was positively correlated with the cell concentration. In addition, there was no link between the incubation time and adsorption rate. The kinetic study showed that the adsorption process fitted well with the pseudo-second-order model, and the adsorption isotherms could be described by both Langmuir and Freundlich equations. Heat and acid treatments showed that the ability of strain RS20 in removing 3-PBA was independent of microbial vitality. Indeed, it was involved with chemisorption and physisorption via the cell walls. The cell walls made the highest contribution to 3-PBA removal, according to the adsorption experiments using different cellular components. This finding was further reconfirmed by SEM. FTIR spectroscopy analysis indicated that carboxyl, hydroxyl, amino groups, and –C–N were the functional sites for the binding of 3-PBA. The co-culture experiments showed that the adsorption of strain RS20 enhanced the degradation of 3-PBA by strain SC-1. Strain RS20 could also survive and effectively remove 3-PBA in simulated digestive juices. Collectively, strain RS20 could be employed as a biological detoxification agent for humans and animals by eliminating 3-PBA from foods, feeds, and the digestive tract in the future.

The Complex Role of Lactic Acid Bacteria in Food Detoxification

Toxic ingredients in food can lead to serious food-related diseases. Such compounds are bacterial toxins (Shiga-toxin, listeriolysin, Botulinum toxin), mycotoxins (aflatoxin, ochratoxin, zearalenone, fumonisin), pesticides of different classes (organochlorine, organophosphate, synthetic pyrethroids), heavy metals, and natural antinutrients such as phytates, oxalates, and cyanide-generating glycosides. The generally regarded safe (GRAS) status and long history of lactic acid bacteria (LAB) as essential ingredients of fermented foods and probiotics make them a major biological tool against a great variety of food-related toxins. This state-of-the-art review aims to summarize and discuss the data revealing the involvement of LAB in the detoxification of foods from hazardous agents of microbial and chemical nature. It is focused on the specific properties that allow LAB to counteract toxins and destroy them, as well as on the mechanisms of microbial antagonism toward toxigenic producers. Toxins of microbial origin are either adsorbed or degraded, toxic chemicals are hydrolyzed and then used as a carbon source, while heavy metals are bound and accumulated. Based on these comprehensive data, the prospects for developing new combinations of probiotic starters for food detoxification are considered.

Acrylamide Elimination by Lactic Acid Bacteria: Screening, Optimization, In Vitro Digestion, and Mechanism

Acrylamide is a toxic compound that is formed in cooked carbohydrate-rich food. Baking, roasting, frying, and grilling are cooking methods that cause its formation in the presence of reducing sugar and asparagine. To prevent acrylamide formation or to remove it after its formation, scientists have been trying to understand acrylamide formation pathways, and methods of prevention and removal. Therefore, this study aimed to: (1) screen newly isolated LAB for acrylamide removal, (2) optimize conditions (pH, temperature, time, salt) of the acrylamide removal for selected LAB isolates using Box-Behnken design (BBD), (3) investigate the acrylamide removal abilities of selected LAB isolates under the in vitro digestion conditions using INFO-GEST2.0 model, and (4) explore the mechanism of the acrylamide removal using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), zeta potential, transmission electron microscopy (TEM) measurement, and Fourier transform infrared spectroscopy (FTIR). Forty strains were tested in MRS broth, where Streptococcus lutetiensis and Lactiplantibacillus plantarum had the highest capability of acrylamide removal by 39% and 26%, respectively. To enhance the binding ability, both strains were tested under controlled conditions of pH (4.5, 5.5 and 6.5), temperature (32 °C, 37 °C and 42 °C), time (14, 18 and 22 h), and NaCl (0%, 1.5% and 3% w/v) using Box-Behnken design (BBD). Both strains removed more acrylamide in the range of 35-46% for S. lutetiensis and 45-55% for L. plantarum. After testing the bacterial binding ability, both strains were exposed to a simulated gastrointestinal tract environment, removing more than 30% of acrylamide at the gastric stage and around 40% at the intestinal stage. To understand the mechanism of removal, LAB cells were characterized via scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM) techniques. Cell charges were characterized by zeta potential and functional groups analyzed by Fourier transform infrared spectroscopy (FTIR). Results indicated that increasing cell wall thickness improved acrylamide adsorption capacity. Both FTIR and EDS indicated that functional groups C=O, C-O, and N-H were associated with acrylamide adsorption.

Removal of patulin by thiol-compounds: A review

Patulin (PAT) is a toxic mycotoxin usually contaminated apple juices, which leads to a serious food safety issue in the world. Thiol-compounds are a class of compounds containing the thiol (-SH) group themselves or obtained the -SH group by physical or chemical modification. They have the ability to efficiently remove patulin in apple juices with manifested negligible effects on juice quality. This review investigates the latest development in the removal of patulin using thiol-compounds, including the removal efficiencies and mechanisms of patulin, the factors influencing the removal efficiency of patulin, as well as the toxicities of thiol-compounds and safety of juices after detoxification. This review shows that thiol-compounds are promising materials for the removal or degradation of patulin in the contaminated juices.

Cell components, interaction types and functional groups involved in the in vitro binding of bisphenol A by Lactiplantibacillus plantarum RS20D and DL7X

AIMS

The current study aimed to evaluate the capacity of two Lactiplantibacillus plantarum strains to remove Bisphenol A (BPA) and to determine the preliminary removal mechanisms underlying this process.

METHODS AND RESULTS

The BPA removal capacity of L. plantarum RS20D and DL7X was assessed by HPLC analysis. The effect of various treatments (physical, chemical, and enzymatic) on two strains were studied to understand which interaction types worked. The different cellular components of them were also subjected to binding assays. Additionally, Fourier-transform infrared spectroscopy (FTIR) was performed to identify the functional groups related to the BPA binding process. Results show that various treatments enhanced the binding capacity of two strains, the effect of sodium dodecyl sulfate was the most outstanding (P=0.000, P=0.000). Hydrogen bonding and hydrophobic interactions likely occurred. Peptidoglycans showed the highest binding capability, protoplasts and teichoic acids might also exert a binding effect. -OH, C=O, -CH, -NH, C-N, C-O, and P=O participated in BPA binding by the two L. plantarum lines.

CONCLUSIONS

Peptidoglycans, protoplasts, and teichoic acid played a vital role in the binding of BPA.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results provided a theoretical foundation for developing effective dietary strategies with foodborne L. plantarum to remove food contaminants.

Critical analysis of peptidoglycan structure of Lactobacillus acidophilus for phthalate removal

Our previous studies have shown that lactic acid bacteria (LABs) can bind and remove di-n-butyl phthalate (DBP), diethyl phthalate, and dioctyl phthalate; three ubiquitous environmental phthalate contaminants. In this study, Lactobacillus acidophilus NCFM was chosen to study the DBP binding mechanism. We found that the three-dimensional structure of the bacterial cell wall, including the carbohydrates and proteins, was essential for DBP adsorption. Peptidoglycan was the main binding component in the cell wall (80.71%), and binding sites exposed to DBP were C-N, N-H, O-H, and C-O bonds. Molecular dynamic (MD) studies demonstrated that hydrophobic interaction plays an important role in DBP adsorption, the chemical sites that influenced the binding in the peptidoglycan model were O2, O3>N1, N2, N3>O1, O4, and the form of adsorption force included hydrogen bonding force, electrostatic force, and van der Waals forces. These theoretical data from the MD simulation were consistent with the experimental results in terms of the ability of this bacterium to bind DBP, so the MD simulation proposed a new way to investigate the mechanisms of phthalate binding to LABs.

Role of the lactobacilli in food bio-decontamination: Friends with benefits

Food contamination such as toxins and heavy metals has been increasing in the last few decades as a result of industrialization in general and as part of food production in particular. Application of microorganisms in toxins and heavy metals bio-removal has been documented and applied as a favorable decontamination approach due to being environmentally friendly, reasonably simple, and economically feasible. Lactobacilli have been proposed and applied as a beneficial biologic sorbent for toxins and heavy metals in processes of reducing their hazardous bio-availability. The purpose of this review is to summarize the known role of Lactobacillus bacterial species in food bio-decontamination processes. After a quick glimpse of the worthy properties of lactobacilli, their cell wall structure is mentioned. Then the potential role of Lactobacillus strains for mycotoxins (aflatoxins, patulin, ochratoxin A, fumonisins, zearalenone, cyanotoxins, and trichothecenes) and heavy metals (lead, arsenic copper, mercury, cadmium, zinc, aluminum, chromium, and iron) bio-removal were described. In addition, the role of various factors in removal yield and the decontamination mechanism were explained. Finally, the lactobacilli-contaminant stability, in vivo studies, and being a friend or foe of Lactobacillus bacteria are discussed.

Adsorption Mechanism of Patulin from Apple Juice by Inactivated Lactic Acid Bacteria Isolated from Kefir Grains

In the food industry, microbiological safety is a major concern. Mycotoxin patulin represents a potential health hazard, as it is heat-resistant and may develop at any stage during the food chain, especially in apple-based products, leading to severe effects on human health, poor quality products, and profit reductions. The target of the study was to identify and characterize an excellent adsorbent to remove patulin from apple juice efficiently and to assess its adsorption mechanism. To prevent juice fermentation and/or contamination, autoclaving was involved to inactivate bacteria before the adsorption process. The HPLC (high-performance liquid chromatography) outcome proved that all isolated strains from kefir grains could reduce patulin from apple juice. A high removal of 93% was found for juice having a 4.6 pH, 15° Brix, and patulin concentration of 100 μg/L by Lactobacillus kefiranofacien, named JKSP109, which was morphologically the smoothest and biggest of all isolates in terms of cell wall volume and surface area characterized by SEM (Scanning electron microscopy) and TEM (transmission electron microscopy). C=O, OH, C–H, and N–O were the main functional groups engaged in patulin adsorption indicated by FTIR (Fourier transform–infrared). E-nose (electronic nose) was performed to evaluate the aroma quality of the juices. PCA (Principal component analysis) results showed that no significant changes occurred between control and treated juice.

Effects of Pretreatments on Patulin Removal from Apple Juices Using Lactobacilli: Binding Stability in Simulated Gastrointestinal Condition and Modeling

Recently, researchers have reported the presence of patulin as a mycotoxin in commercial apple products, especially apple juices. The aim of this study was to assess adsorption of patulin from artificially contaminated apple juice using two lactic acid bacteria (LAB) strains of Lactobacillus acidophilus ATCC 4356 and Lactobacillus plantarum ATCC 8014. Furthermore, effects of five physical and chemical pretreatments on the patulin adsorption were investigated. Results demonstrated that patulin adsorption abilities of both strains increased with NaOH pretreatment but decreased after autoclaving. The NaOH-treated L. plantarum ATCC 8014 showed the best removal rate (59.74%) after 48 h of refrigerated storage, compared with the NaOH-treated L. acidophilus ATCC 4356 (52.36%). Moreover, stability of the LAB-patulin complex was assessed in simulated gastrointestinal tract conditions and a low quantity of patulin was released into the solution. The patulin adsorption process by NaOH-treated L. plantarum ATCC 8014 followed Freundlich isotherm model and pseudo-second-order kinetic model. Fourier transform infrared spectroscopy showed that polysaccharide and protein components of the L. plantarum ATCC 8014 cell wall played key roles in patulin adsorption. The major functional groups of the cell wall that were involved in adsorbing patulin included -OH/-NH, -CH₂, C=O, and C-O groups. The current results suggest that NaOH-treated L. plantarum ATCC 8014 cells include the potential to detoxify patulin-contaminated apple juices.

Microorganisms, the Ultimate Tool for Clean Label Foods?

Clean label is an important trend in the food industry. It aims at washing foods of chemicals perceived as unhealthy by consumers. Microorganisms are present in many foods (usually fermented), they exhibit a diversity of metabolism and some can bring probiotic properties. They are usually well considered by consumers and, with progresses in the knowledge of their physiology and behavior, they can become very precise tools to produce or degrade specific compounds. They are thus an interesting means to obtain clean label foods. In this review, we propose to discuss some current research to use microorganisms to produce clean label foods with examples improving sensorial, textural, health and nutritional properties.

Patulin in food: A mycotoxin concern for human health and its management strategies

The mycotoxin patulin is primarily produced as a secondary metabolite by numerous fungal species and predominantly by Aspergillus, Byssochlamys, and Penicillium species. It is generally associated with fungal infected food materials. Penicillium expansum is considered the only fungal species liable for patulin contamination in pome fruits, especially in apples and apple-based products. This toxin in food poses serious health concerns and economic threat, which has aroused the need to adopt effective detection and mitigation strategies. Understanding its origin sources and biosynthetic mechanism stands essential for efficiently designing a management strategy against this fungal contamination. This review aims to present an updated outline of the sources of patulin occurrence in different foods and their biosynthetic mechanisms. It further provides information regarding the detrimental effects of patulin on human and agriculture as well as its effective detection, management, and control strategies.

In Vitro Mechanism Assessment of Zearalenone Removal by Plant-Derived Lactobacillus plantarum BCC 47723

Zearalenone (ZEA) is a harmful secondary fungal metabolite, produced primarily by plant pathogenic fungi mostly belonging to the genus Fusarium. It is involved in reproductive disorders in animals since its structure is similar to the estrogen hormone. This induces precocious pubertal changes, fertility problems, and hyper estrogenic disorders. The main objectives of this study were to evaluate the ZEA removal capacity of plant-derived lactic acid bacteria (LAB) and to investigate the possible components and mechanisms involved in the removal of ZEA by physically and chemically treated plant-derived LAB. The bacterial cells were characterized using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), and the analysis of zeta potential, and hydrophobic index. Results revealed that 17 out of 33 plant-derived LAB exhibited ZEA removal from liquid medium. The percentage of removal ranged from 0.5-23% and Lactobacillus plantarum BCC 47723, isolated from wild spider flower pickle (Pag-sian-dorng), exhibited the highest removal. The alteration of proteins on L. plantarum BCC 47723 structure by Sodium dodecyl sulphate (SDS) treatment was positively affected on ZEA removal, whereas that of lipids on ZEA removal was negatively observed. Heat treatment influenced the higher ZEA adsorption. SEM images showed that the morphologies of modified bacterial cells were distinctly deformed and damaged when compared with untreated control. FTIR analysis indicated that the original functional groups, which included amide (C=O, C-N), carboxyl (C=O, C-O, O-H), methylene (C=C), and alcohol (O-H) groups, were not changed after ZEA adsorption. The zeta potential indicated that electrostatic interaction was not involved in the ZEA removal, while hydrophobicity was the main force to interact with ZEA. These findings can conclude that adsorption by hydrophobicity is the main mechanism for ZEA removal of plant-derived L. plantarum BCC 47723. The alteration of bacterial cell structure by heat treatment enhanced the efficiency of L. plantarum BCC 47723 for ZEA reduction. Its activity can be protected by the freeze-drying technique. Hence, plant-derived L. plantarum BCC 47723 can be considered as an organic adsorbent for ZEA reduction in food and feedstuff.

Key role of exopolysaccharide on di-butyl phthalate adsorbing by Lactobacillus plantarum CGMCC18980

Abstract

Plasticizers belong to hormone-like substances existing widely in the environment. According to the Environmental Protection Agency of China, they are considered to be the fourth class of toxic chemicals due to their harmful effects on normal endocrine system in human bodies. In the recent published work of our lab, Lactobacillus plantarum CGMCC18980 (strain P1) could reduce the toxicity of di-butyl phthalate (DBP) in rats effectively. The purpose of this study is to further explore the adsorption mechanism of di-butyl phthalate to L. plantarum CGMCC18980, based on optimizing the adsorption conditions. As a consequence, the adsorption effect of L. plantarum CGMCC18980 attributed to relationships between exopolysaccharide, membrane protein, and the cell wall. Experimental results demonstrated that exopolysaccharide and the cell wall were devoted to DBP binding. An obvious adsorption layer was observed outside of L. plantarum CGMCC18980 through scanning electron microscope (SEM) and transmission electron microscope (TEM). The Fourier transform infrared spectroscopy (FTIR) results showed that the functional groups involved in adsorption were mainly C=O, C-N, and C-O, which related to lipids and polysaccharides. Zeta potential analysis indicated that DBP adsorption had no significant relationship with surface charge. These results revealed that exopolysaccharide may be the key factor of strain CGMCC18980 in DBP adsorption.

Key points

• Lactobacillus plantarum CGMCC18980 has the ability to adsorb di-butyl phthalate, reaching to 58.63%.

• Exopolysaccharide is considered to play a key role in adsorption process.

• Membrane protein, cell wall, and surface charge do not contribute to adsorption.

Removal of aflatoxin b1 and t-2 toxin by bacteria isolated from commercially available probiotic dairy foods

This study isolated lactic acid bacteria from commercially available probiotic foods to determine their capacity to remove aflatoxin B₁ (AFB₁) and trichothecene-2 (T-2). The removal rates by original live and heat-treated cells of lactic acid bacteria (LAB) were compared to test the effect of heat treatment on efficacy. LAB is capable to remove up to 46% of AFB₁ and up to 45% of T-2 toixn. The toxin removal capability increased as toxin concentration increased despite bacterial cell viability declining. Surprisingly, the denatured LAB removed greater percentages of AFB₁ (up to 62%) and T-2 (up to 52%) than live bacterial cells (P < 0.05), lending support to the hypothesis that there is higher binding of toxins to the cell membrane of nonviable cells. The research provided practical evidences, which suggest that when ingested into the gut biota, LAB could likely reduce absorption of AFB₁ and T-2 from contaminated foods.

The In Vitro Adsorption Ability of Lactobacillus acidophilus NCFM to Benzo(a)pyrene in PM2.5

The objective of this work was to explore the ability of lactic acid bacteria strains to bind benzo(a)pyrene (B(a)P) existing in PM_2.5. In this study, we examined the ability of Lactobacillus acidophilus NCFM to bind B(a)P in the simulated PM_2.5 environment. Among the tested 5 strains, Lactobacillus acidophilus NCFM exhibited the best capacity to bind B(a)P, and its B(a)P binding percentage was 60.00%. Simulations of organic and inorganic systems which represent PM_2.5 indicated that B(a)P could be absorbed by strain L. acidophilus NCFM. For the inorganic system of pH 5, L. acidophilus NCFM bound 92.74% B(a)P with a cell concentration of 1 × 10¹⁰ cfu/mL at 37°C for 8 hr. Regarding the organic system with pH 6, 73.00% B(a)P was bound by strain L. acidophilus NCFM after this bacterium was incubated at 37°C for 10 min. A quick B(a)P binding by this probiotic bacterium took place in the organic system. The removal of B(a)P from PM_2.5 was significantly related to incubation time, cultivation temperature, pH, and cell concentration. Thus, our finding shows that long-term consumption of L. acidophilus NCFM is beneficial for the reduction of B(a)P towards the population who are exposed to PM_2.5, although the ability of this bacterium to adsorb B(a)P is partly affected by the differences in the origin of PM_2.5.

Prevention and detoxification of patulin in apple and its products: A review

Patulin-producing fungi pose an unavoidable problem for apple and its product quality, thereby threatening human and/or animal health. Studies on controlling the patulin-producing fungal growth and patulin contamination in apple and its products by physical methods, chemical fungicides, and biological methods have been performed for decades, but patulin contamination has not been addressed. Here, the important of studying regulation mechanism of patulin production in apple at the protein expression and metabolism levels is proposed, which will facilitate the development of controlling patulin production by using physical, chemical, and biological methods. Furthermore, the advantages or disadvantages and effects or mechanisms of using physical, chemical, biological methods to control the decay caused by Penicillium expansum and to remove patulin in food was discussed. The development of physical methods to remove patulin depends on the development of special equipment. Chemical methods are economical and efficient, if we have ensured that there are no unknown reactions or toxic by-products by using these chemicals. The biological method not only effectively controls the decay caused by Penicillium espansum, but also removes the toxins that already exist in the food. Degradation of patulin by microorganisms or biodegradation enzymes is an efficient and promising method to remove patulin in food if the microorganisms used and the degradation products are completely non-toxic.

Leuconostoc mesenteroides subsp. mesenteroides LB7 isolated from apple surface inhibits P. expansum in vitro and reduces patulin in fruit juices

This research aimed to isolate lactic acid bacteria (LAB) from apple surface and to reveal their potential to inhibit the growth of Penicillium expansum. Besides, their ability to detoxify fruit juices contaminated with mycotoxin patulin, produced by this fungi, was also studied. The isolation was performed on a typical MRS medium under ambient conditions. The molecular identification of the strains was done by sequencing the 16S rRNA genes. Antifungal activities of the isolated strains have been evaluated using dual agar plate assay protocol. A total of 11 LAB isolates was obtained from apples. These isolates showed phenotypic traits consistent with the genera of LAB. They have been identified as Leuconostoc mesenteroides subsp. mesenteroides and Weissella paramesenteroides. Among them, the strain LB7 showed exciting inhibitory activities in vitro against P. expansum. LB7 also successfully detoxified homemade and commercial fruit juices contaminated with patulin. Further research will bring the application prospects of these LABs in food biocontrol and biopreservation strategies.

Adsorption kinetics and mechanism of di-n-butyl phthalate by Leuconostoc mesenteroides

Di-n-butyl phthalate (DBP) poses a risk to humans as a ubiquitous environmental contaminant. A strain of Leuconostoc mesenteroides DM12 was chosen from lactic acid bacteria strains to study the DBP binding mechanisms. Adsorption of DBP by strain DM12 reached the highest binding rate of 87% after 11 hr of incubation, which could be explained by pseudo-second-order kinetics. The adsorption isotherm coincided with the model of Langmuir-Freundlich, indicating physical and chemical adsorption processes involved. Further, NaIO4 and TCA treatments were used to analyze the DBP binding mechanism of strain DM12, which indicated that peptidoglycan on the bacterial cell wall was involved in the process. The O-H, C-O, and N-H bonds were possibly involved in the binding process as the main functional groups.

The characteristics of patulin detoxification by Lactobacillus plantarum 13M5

Patulin (PAT) is a widespread mycotoxin that harms the health of both humans and animals. In this study, among the 17 tested Lactobacillus plantarum strains, L. plantarum 13M5, isolated from traditional Chinese fermented foods, showed the highest PAT degradation rate of up to 43.8% (PAT 5 mg/L). Evaluation of the living and dead 13M5 cells revealed that only the living cells had the ability to remove PAT and degrade it into E-ascladiol. A cell-based assay revealed that L. plantarum 13M5 administration alleviated PAT-induced injuries in Caco-2 cells, including cytotoxicity, oxidative stress, and tight junction disruption. Our results suggest that L. plantarum 13M5 has the potential to reduce PAT toxicity and can thus be used as a probiotic supplement to reduce or eliminate the toxicity of PAT ingested from diet.

Lead and cadmium biosorption from milk by Lactobacillus acidophilus ATCC 4356

The food and water contamination with heavy metals is increasing due to the environmental pollutions. Lead and cadmium are the toxic heavy metals for humans that can be found in air, soil, water, and even food. Lactic acid bacteria have the ability to remove and diminish the level of heavy metals. In this study, Lactobacillus acidophilus was used to remove lead and cadmium in milk and the capability of this valuable bacterium in biosorption of these metals low concentrations (µg/L or ppb) in milk was evaluated. First, the variables on lead and cadmium removal by this bacterium have been studied by Plackett-Burman design. Then, the bioremoval process was optimized and the three main factors, the bacterium concentration, contact time, and the initial heavy metal concentration were chosen by using a central composite design. The optimum lead and cadmium bioremoval yield of 80% and 75% were observed, respectively, at 1 × 1012 CFU of L. acidophilus in milk at the 4th day and the initial ion concentration of 100 µg/L. The 3D plots analysis showed the interaction effects on metal biosorption. This study showed that L. acidophilus is a natural effective biosorbent for lead and cadmium removal from milk.

Decontamination of Aflatoxins by Lactic Acid Bacteria

Aflatoxins are toxic secondary metabolic products, which exert great hazards to human and animal health. Decontaminating aflatoxins from food ingredients to a threshold level is a prime concern for avoiding risks to the consumers. Biological decontamination processes of aflatoxins have received widespread attention due to their mild and environmental-friendly nature. Many reports have been published on the decontamination of aflatoxins by microorganisms, especially lactic acid bacteria (LAB), a well-explored probiotic and generally recognized as safe. The present review aims at updating the decontamination of produced aflatoxins using LAB, with an emphasis on the decontamination mechanism and influence factors for decontamination. This comprehensive analysis provides insights into the binding mechanisms between LAB and aflatoxins, facilitating the theoretical and practical application of LAB for decontaminating hazardous substances in food and agriculture.