Antifungal and antimycotoxigenic effect of Lactobacillus plantarum CRL 778 at different water activity values

Apical-out intestinal organoids as an alternative model for evaluating deoxynivalenol toxicity and Lactobacillus detoxification in bovine

Small intestinal organoids are similar to actual small intestines in structure and function and can be used in various fields, such as nutrition, disease, and toxicity research. However, the basal-out type is difficult to homogenize because of the diversity of cell sizes and types, and the Matrigel-based culture conditions. Contrastingly, the apical-out form of small intestinal organoids is relatively uniform and easy to manipulate without Matrigel. Therefore, we sought to investigate the possibility of replacing animal testing with bovine apical-out small intestinal organoids (Apo-IOs) by confirming the toxicity of mycotoxins and effectiveness of L. plantarum as mycotoxin-reducing agents. The characteristics and functions of Apo-IOs were first confirmed. The gene and protein expression of stem cell, proliferation, mucous, and adherence markers were detected, and the absorption capacity of amino and fatty acids was also confirmed. FITC-4 kDa dextran, a marker of intestinal barrier function, did not penetrate the Apo-IOs, confirming the role of the organoids as a barrier. However, when co-treated with deoxynivalenol (DON), FITC-4 kDa dextran was detected deep within the organoids. Moreover, qPCR and immunofluorescence staining confirmed a decrease in the expression of key markers, such as LGR5, Ki67, Mucin2, Villin2, and E-cadherin. In addition, when Apo-IOs were treated with Lactobacillus plantarum ATCC14917 culture supernatant (LCS) and DON together, cell death was reduced compared to when treated with DON alone, and FITC-4 kDa dextran was confirmed to flow only to the peripheral part of the organoid. The qPCR and immunofluorescence staining results of LCS and DON co-treatment group showed that LGR5, Ki67, Mucin2, Villin2, and E-cadherin were expressed at significant higher levels than those in the DON treatment group alone. In this study, we found that the characteristics and functions of bovine Apo-IOs were similar to those of the intestinal structure in vivo. Additionally, the effects of mycotoxins and effectiveness of L. plantarum as mycotoxin-reducing agents were confirmed using bovine Apo-IOs. Therefore, bovine Apo-IOs could be applied in toxicity studies of mycotoxins and could also be used as in vitro models to replace animal testing and improve animal welfare.

Type III sourdough: Evaluation of biopreservative potential in bakery products with enhanced antifungal activity

The potential biopreservative role of a Type III sourdough (tIII-SD), produced by starter cultures of Fructilactobacillus sanfranciscensis and Lactiplantibacillus plantarum ATCC 8014, was assessed for its antifungal activity in baking applications. Fermentation was carried out using different substrates to enhance the production of antifungal metabolites for 24 and 48 h. The tIII-SD samples were analyzed in relation to pH, total titratable acidity (TTA) and the production of organic acids. The water/salt-soluble extract of the tIII-SD was evaluated in relation to the inhibition potential against key fungi that contaminate bakery products including Penicillium roqueforti, Penicillium chrysogenum and Aspergillus niger. Finally, breads with 10 % of the tIII-SD were prepared and the fungi contamination was evaluated throughout the shelf life period. The lowest pH value in sourdough was obtained from 48-hour fermentation by L. plantarum. The saline extracts exhibited varying degrees of inhibition in the in vitro test; however, the greatest enhancement of this effect was obtained when whole wheat grain flour was used. The tIII-SD crafted from a blend of wheat and flaxseed flours and fermented with F. sanfranciscensis for 48 h (BSWF48h-FS), demonstrated superior performance compared to other formulations. This variant exhibited a total shelf life of 10 days, suggesting that the utilization of tIII-SD could serve as a viable alternative for natural antifungal agents, proving beneficial for the bakery industry.

Reusable thiol-modification Lactobacillus plantarum embedded in cellulose nanocrystals composite aerogel for efficient removal of Ochratoxin A in grape juice

Ochratoxin A (OTA) contamination in grape juice has attracted widespread concern as OTA can lead to kidney disease and cause adverse neurological effects. An effective method to remove OTA is to make use of highly adsorbent materials that are able to remove the toxic contaminant. Recently, inactivated Lactobacillus plantarum-based biosorbents have shown to be an efficient, cost-effective and environmentally friendly bioremediation method in removing toxic pollutants such as OTA. We used five chemical thiol-modification methods to improve the adsorption efficiency of OTA in grape juice. The esterification of Lactobacillus plantarum (L-Es) significantly increased the sulfhydryl contents (-SH) by 251.33 μmol/g and >90% of OTA was removed. However, the inactivated microbial adsorbent was difficult to separate after adsorption and therefore, the prepared L-Es were embedded into the cellulose nanocrystals (L-Es@CNCs). Moreover, L-Es@CNCs significantly increased the adsorption rate of OTA in grape juice samples by 88.28% with negligible effects on juice quality due to the properties of easy re-use and excellent biodegradability. This showcases its potential application for OTA removal in the grape juice industry.

Anti-Spoilage Activity and Exopolysaccharides Production by Selected Lactic Acid Bacteria

In this study, eight lactic acid bacteria (LAB) strains, previously isolated from traditional and gluten-free sourdoughs, and selected for their potential in improving the sensory and rheological quality of bakery products, were screened against some common spoilage agents. The anti-mould activity was tested using strains of the species Fusarium graminearum, Aspergillus flavus, Penicillium paneum and Aspergillus niger. Regarding the antibacterial activity, it was assessed against four strains of the species Escherichia coli, Campylobacter jejuni, Salmonella typhimurium and Listeria monocytogenes. Furthermore, LAB strains were evaluated for their ability to produce exopolysaccharides, which are gaining considerable attention for their functional properties and applicability in different food industrial applications. A strain-specific behaviour against the moulds was observed. In particular, F. graminearum ITEM 5356 was completely inhibited by all the LAB strains. Regarding the antibacterial activity, the strains Leuconostoc citreum UMCC 3011, Lactiplantibacillus plantarum UMCC 2996, and Pediococcus pentosaceus UMCC 3010 showed wide activity against the tested pathogens. Moreover, all the LAB strains were able to produce exopolysaccharides, which were preliminarily characterized. The assessed features of the LAB strains allow us to consider them as promising candidates for single or multiple starter cultures for food fermentation processes.

Antifungal Metabolites as Food Bio-Preservative: Innovation, Outlook, and Challenges

Perishable food spoilage caused by fungi is a major cause of discomfort for food producers. Food sensory abnormalities range from aesthetic degeneration to significant aroma, color, or consistency alterations due to this spoilage. Bio-preservation is the use of natural or controlled bacteria or antimicrobials to enhance the quality and safety of food. It has the ability to harmonize and rationalize the required safety requirements with conventional preservation methods and food production safety and quality demands. Even though synthetic preservatives could fix such issues, there is indeed a significant social need for "clean label" foods. As a result, consumers are now seeking foods that are healthier, less processed, and safer. The implementation of antifungal compounds has gotten a lot of attention in recent decades. As a result, the identification and characterization of such antifungal agents has made promising advances. The present state of information on antifungal molecules, their modes of activity, connections with specific target fungi varieties, and uses in food production systems are summarized in this review.

Enterococcus faecium: a promising protective culture to control growth of ochratoxigenic moulds and mycotoxin production in dry-fermented sausages

Moulds positively contribute to the development of typical characteristic flavour and aroma of dry-fermented sausages. However, some mould species, such as Penicillium nordicum and Penicillium verrucosum, may contaminate this product with ochratoxin A (OTA). For this reason, the control of toxigenic moulds is needed. Strategies based on the use of antifungal microorganisms present in the native microbial population in the dry-fermented sausage processing could be a promising strategy. The aim of this work was to study the effect of Enterococcus faecium strains on P. nordicum and P. verrucosum growth and OTA production in a dry-fermented sausage-based medium at conditions of temperature and water activity similar to those occurring during the ripening of these meat products. Six strains were screened to evaluate their growth capacity and antifungal activity against P. nordicum and P. verrucosum at three fixed temperatures related to the sausage ripening. The two E. faecium strains that decreased growth of both species were chosen to further evaluate their effect on growth of P. verrucosum and P. nordicum and their mycotoxin production under conditions simulating the dry-fermented sausage ripening. The presence of E. faecium SE920 significantly reduced OTA production of P. nordicum although it did not affect P. verrucosum. E. faecium SE920, isolated from dry-fermented sausages, could be a good candidate to reduce OTA production by P. nordicum in dry-fermented sausages.