Salt is widely employed in different foods, especially in meat products, due to its very diverse and extended functionality. However, the high intake of sodium chloride in human diet has been under consideration for the last years, because it is related to serious health problems. The meat-processing industry and research institutions are evaluating different strategies to overcome the elevated salt concentrations in products without a quality reduction. Several properties could be directly or indirectly affected by a sodium chloride decrease. Among them, microbial stability could be shifted towards pathogen growth, posing a serious public health threat. Nonetheless, the majority of the literature available focuses attention on the sensorial and technological challenges that salt reduction implies. Thereafter, the need to discuss the consequences for shelf-life and microbial safety should be considered. Hence, this review aims to merge all the available knowledge regarding salt reduction in meat products, providing an assessment on how to obtain low salt products that are sensorily accepted by the consumer, technologically feasible from the perspective of the industry, and, in particular, safe with respect to microbial stability.

The resident microbiome in food industries may impact on food quality and safety. In particular, microbes residing on surfaces in dairy industries may actively participate in cheese fermentation and ripening and contribute to the typical flavor and texture. In this work, we carried out an extensive microbiome mapping in 73 cheese-making industries producing different types of cheeses (fresh, medium and long ripened) and located in 4 European countries. We sequenced and analyzed metagenomes from cheese samples, raw materials and environmental swabs collected from both food contact and non-food contact surfaces, as well as operators’ hands and aprons. Dairy plants were shown to harbor a very complex microbiome, characterized by high prevalence of genes potentially involved in flavor development, probiotic activities, and resistance to gastro-intestinal transit, suggesting that these microbes may potentially be transferred to the human gut microbiome. More than 6100 high-quality Metagenome Assembled Genomes (MAGs) were reconstructed, including MAGs from several Lactic Acid Bacteria species and putative new species. Although microbial pathogens were not prevalent, we found several MAGs harboring genes related to antibiotic resistance, highlighting that dairy industry surfaces represent a potential hotspot for antimicrobial resistance (AR) spreading along the food chain. Finally, we identified facility-specific strains that can represent clear microbial signatures of different cheesemaking facilities, suggesting an interesting potential of microbiome tracking for the traceability of cheese origin.

To study the quality of chorizo de León dry fermented sausages (DFS), high pressure processing (HPP) applied at the early stages of ripening and the use of a functional starter culture were evaluated as additional safety measures. Furthermore, the ability to control the populations of artificially inoculated Listeria monocytogenes and Salmonella Typhimurium was investigated and the evolution of microbial communities was assessed by amplicon 16S rRNA metataxonomics. The use of HPP and the starter culture, independently or combined, induced a reduction of Listeria monocytogenes of 1.5, 4.3 and > 4.8 log CFU/g respectively, as compared to control. Salmonella Typhimurium counts were under the detection limit (<1 log) in all treated end-product samples. Both additional measures reduced the activity of undesirable microbiota, such as Serratia and Brochothrix, during the production of DFS. Moreover, the starter culture highly influencedthe taxonomic profile of samples.No adverse sensory effects were observed, and panelists showed preference for HPP treated DFS. In conclusion, this new approach of applying HPP at the early stages of ripening of DFS in combination with the use of a defined starter culture improved the safety and quality of the meat product.

Four strains, representing two novel Bifidobacterium species, were isolated from water kefir, a fermented beverage. 16S rRNA gene analysis suggested that the novel species share high identities (98.82–98.89%) with Bifidobacterium aquikefiri LMG 28769^T. Complete genomes were assembled with a short- and long-read hybrid sequencing approach. In agreement with the 16S rRNA gene analysis, phylogenetics with 117 marker genes places the novel species closest to B. aquikefiri LMG 28769^T as well. The isolates have average nucleotide identity (ANI) scores ranging from 81.46 to 84.84% and digital DNA–DNA hybridization (dDDH) scores from 23.9 to 38.5% with the closest related species, as well as ANI scores between the proposed new species of 80.50%, indicating that the isolates represent two novel species. Matrix-assisted laser desorption/ionization-time of flight chemotaxonomic analysis supported the gene-based taxonomic placement. We propose the names Bifidobacterium fermentum sp. nov. and Bifidobacterium aquikefiricola sp. nov. for these novel species within the Bifidobacterium genus. The proposed type strain B. fermentum WK012_4_13^T (= LMG 33104^T = DSM 116073^T; GenBank accession number GCF_041080835.1) has a genome size of 2.43 Mbp, with a G+C content of 56.00 mol%. The proposed type strain for B. aquikefiricola WK041_4_12^T (= LMG 33105^T = DSM 116074^T; GenBank accession number GCF_041080795.1) has a genome size of 2.36 Mbp and a G+C content of 53.94 mol%. B. fermentum cells are Gram-positive staining, non-motile, non-spore-forming, fructose-6-phosphate phosphoketolase (F6PPK)-positive, catalase- and oxidase-negative and bacillary club shaped. B. aquikefiricola cells are Gram-positive staining, non-motile, non-spore-forming, F6PPK-positive, catalase- and oxidase-negative and square rod shaped.