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Food-fermenting lactic acid bacteria (LAB) are generally considered to be non-toxic and non-pathogenic. Some species of LAB, however, can produce biogenic amines (BAs). BAs are organic, basic, nitrogenous compounds, mainly formed through decarboxylation of amino acids. BAs are present in a wide range of foods, including dairy products, and can occasionally accumulate in high concentrations. The consumption of food containing large amounts of these amines can have toxicological consequences. Although there is no specific legislation regarding BA content in many fermented products, it is generally assumed that they should not be allowed to accumulate. The ability of microorganisms to decarboxylate amino acids is highly variable, often being strain specific, and therefore the detection of bacteria possessing amino acid decarboxylase activity is important to estimate the likelihood that foods contain BA and to prevent their accumulation in food products. Moreover, improved knowledge of the factors involved in the synthesis and accumulation of BA should lead to a reduction in their incidence in foods. European Journal of Clinical Nutrition (2010) 64, S95-S100; doi: 10.1038/ejcn.2010.218 Keywords: biogenic amines; lactic acid bacteria; risk assessment; food fermentation; acid stress;toxicological effects, Introduction Lactic acid bacteria (LAB) can produce metabolic energy and/ or increase their acid resistance by using catabolic pathways that convert amino acids into amine-containing compounds referred to as biogenic [...]

m. coton, j.m. laplace and e. coton. 2004.To identify strains ofZymomonas mobilisat the subspecies level by a fast and reliable technique.Amplified ribosomal DNA restriction analysis (ARDRA) was used to identify strains ofZ. mobilisat the subspecies level using the restriction enzymeStuI. This technique allowed for easy and quick differentiation betweenZ. mobilissubsp.mobilisandZ. mobilissubsp.pomaceae. By using other enzymes, the presence of two ARDRA profiles within the subspeciesZ. mobilissubsp.pomaceaewas observed, one profile corresponded to collection strains (British origin) while the other corresponded to wild type strains isolated from‘framboisé’ ciders in France.A rapid method for identification of strains ofZ. mobilisat the subspecies level was developed and shown to be more reliable and faster than the conventional method based on physiological tests. Furthermore, consistent differences in the 16S rDNA sequences between collection and wild type strains ofZ. mobilissubsp.pomaceaewere observed suggesting that the French isolates correspond to a new genomovar within this subspecies.This is the first description of a molecular method for the identification ofZ. mobilisstrains at the subspecies level. It will certainly prove to be useful in identifying this beer and cider spoiling micro-organism. [ABSTRACT FROM AUTHOR]

Abstract: Biodiversity of 17 Zymomonas mobilis strains isolated from French “framboisé” ciders from 7 different geographical areas of France was analysed using random amplified polymorphic DNA (RAPD) and 6 different strain fingerprints were observed. One of the fingerprints was identical for 10 of the 17 cases. No correlation between geographical origin and strain fingerprint was observed. In parallel, the cider-making process was followed from the orchard to the final product for Z. mobilis presence. Detection of the bacterium only occurred during the fermentation process. The French isolate, strain AN0101, recently proposed as a novel subspecies (Z. mobilis subsp. francensis) was characterized in a synthetic medium using various growth conditions that can be encountered during cider-making (T (°C), pH, ethanol, SO2, polyphenols) to determine growth limits. Results clearly showed that cider is in a risk zone for Z. mobilis contamination as this bacterium was able to grow at temperatures as low as 4°C, in pH range from 3.5 to 6.0, in 0–8ml/100ml ethanol, at the legal limit of 200mg/l SO2 and in the presence of a cider marc polyphenol extract up to 3g/l. These results should allow for a better understanding of Z. mobilis conditions of contamination in cider and lead to possible preventive measures in the future. [Copyright &y& Elsevier]

In walnut orchards, frequent symptoms of cankers and dieback (fruit blight, twig and branch cankers up to tree death) are caused by different agents, in particular by Botryosphaeriaceae, primarily Neofusicoccum parvum and Botryosphaeria dothidea. This study aimed at developing a sensitive, rapid, specific and internally controlled multiplex PCR assay for the detection of these species. The ability of the multiplex PCR, with an internal inhibition control (i.e. E. coli DNA), to specifically and successfully detect members of the two targeted species was validated using 11 different isolates for each fungal target (inclusivity) and 20 tree-associated fungal species different from B. dothidea or N. parvum (exclusivity). Applicability to plant materials was further investigated and showed an absence of amplification for asymptomatic husk or twig samples while the amplification profiles of symptomatic tissues ranged from no amplification to amplification of both species, in correlation with the observed fungal contamination level. In conclusion, we developed a rapid diagnostic tool for simultaneous detection of two major fungal pathogens of walnut. Although this protocol was tailored for walnut husks and twigs, applicability to any plant sample contaminated by these pathogens can be considered., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Among cereal contaminants, mycotoxins are of concern due to their importance in terms of food and feed safety. The difficulty in establishing a diagnosis for mycotoxicosis relies on the fact that the effects are most often subclinical for chronic exposure and the most common scenario is multi-contamination by various toxins. Mycotoxin co-occurrence is a major food safety concern as additive or even synergic toxic impacts may occur, but also regarding current regulations as they mainly concern individual mycotoxin levels in specific foods and feed in the food chain. However, due to the large number of possible mycotoxin combinations, there is still limited knowledge on co-exposure toxicity data, which depends on several parameters. In this context, this systematic review aims to provide an overview of the toxic effects of two regulated mycotoxins, namely ochratoxin A and fumonisin B1. This review focused on the 2012-2022 period and analysed the occurrence in Europe of the selected mycotoxins in different food matrices (cereals and cereal-derived products), and their toxic impact, alone or in combination, on in vitro intestinal and hepatic human cells. To better understand and evaluate the associated risks, further research is needed using new approach methodologies (NAM), such as in vitro 3D models. KEY CONTRIBUTION: Cereals and their derived products are the most important food source for humans and feed for animals worldwide. This manuscript is a state of the art review of the literature over the last ten years on ochratoxin A and fumonisin B1 mycotoxins in these products in Europe as well as their toxicological effects, alone and in combination, on human cells. Future perspectives and some challenges regarding the assessment of toxicological effects of mycotoxins are also discussed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Plastic pollution of the ocean is a major environmental threat. In this context, a better understanding of the microorganisms able to colonize and potentially degrade these pollutants is of interest. This study explores the colonization and biodegradation potential of fungal communities on foamed polystyrene and alternatives biodegradable plastics immersed in a marina environment over time, using the Brest marina (France) as a model site. The methodology involved a combination of high-throughput 18S rRNA gene amplicon sequencing to investigate fungal taxa associated with plastics compared to the surrounding seawater, and a culture-dependent approach to isolate environmentally relevant fungi to further assess their capabilities to utilize polymers as carbon sources. Metabarcoding results highlighted the significant diversity of fungal communities associated with both foamed polystyrene and biodegradable plastics, revealing a dynamic colonization process influenced by the type of polymer and immersion time. Notably, the research suggests a potential for certain fungal species to utilize polymers as a carbon source, emphasizing the need for further exploration of fungal biodegradation potential and mechanisms.

Meat dry aging consists in storing unpackaged meat in a cold room, and at a specific and controlled relative humidity (RH), for a period of 1 to 5 weeks or more. This practice has become widespread in recent years due to its positive effect on the tenderness of the meat but also on other organoleptic characteristics and therefore its market value. The objective of this work was to study the bacterial and fungal microbiota of dry-aged beef at the commercial stage by both culture-dependent and -independent approaches. Fifty-eight samples of dry-aged meat from different producer types (meat processing plants, artisanal and supermarket butchers) were studied. The dry-aging conditions (temperature, RH) of the meats, as well as the surface pH and a w , were measured. The main microbial groups were enumerated by culture on various dedicated media. Concerning fungi, isolates of yeasts and molds (n = 257) were identified after dereplication by FTIR spectroscopy and/or sequencing of taxonomically relevant genes (26S rDNA, ITS, β-tubulin, actin). Metagenetic analyzes targeting the V3-V4 regions of 16S rDNA and ITS2 were also performed. Overall, ripening practices were diversified with temperatures and RH between 0.5 and 2.8 °C (median = 2 °C) and 47 and 88 % (median = 70 %), respectively. The aerobic colony count varied between 1.97 and 10.91 log 10 CFU/g (median = 8.32 log 10 CFU/g) and was similar to that of Pseudomonas spp., indicating that this bacterial group was dominant. Yeast populations varied between <2 and 9.41 log 10 CFU/g, while molds showed abundances between <2 and 7.7 log 10 TFU/g, the highest values being found in meats matured with a high RH. Bacterial and mold counts were positively correlated with the dry-aging RH and, to a lesser extent, temperature. The main yeast species were Candida zeylanoides and Yarrowia alimentaria as well as Itersonilia pannonica (identified only in metagenetics). The dominant mold species were psychrophilic or psychrotrophic species, namely Mucor complex flavus and Helycostylum elegans/pulchrum that have already been shown to be associated with dry-aged beef meat. This study has identified the main microorganisms associated with dry-aged meat in France, which raises the question of their role in the organoleptic quality of these higher value products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Traditional products are particularly appreciated by consumers and among these products, cheese is a major contributor to the Italian mountainous area economics. In this study, shotgun metagenomics and volatilomics were used to understand the biotic and abiotic factors contributing to mountain Caciotta cheese typicity and diversity. Results showed that the origin of cheese played a significant role; however, curd cooking temperature, pH, salt concentration and water activity also had an impact. Viral communities exhibited higher biodiversity and discriminated cheese origins in terms of production farms. Among the most dominant bacteria, Streptococcus thermophilus showed higher intraspecific diversity and closer relationship to production farm when compared to Lactobacillus delbrueckii. However, despite a few cases in which the starter culture was phylogenetically separated from the most dominant strains sequenced in the cheese, starter cultures and dominant cheese strains clustered together suggesting substantial starter colonization in mountain Caciotta cheese. The Caciotta cheese volatilome contained prominent levels of alcohols and ketones, accompanied by lower proportions of terpenes. Volatile profile not only demonstrated a noticeable association with production farm but also significant differences in the relative abundances of enzymes connected to flavor development. Moreover, correlations of different non-homologous isofunctional enzymes highlighted specific contributions to the typical flavor of mountain Caciotta cheese. Overall, this study provides a deeper understanding of the factors shaping typical mountain Caciotta cheese, and the potential of metagenomics for characterizing and potentially authenticating food products., Competing Interests: Declaration of competing interest None., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)