Microbial contamination of food and alimentary toxoinfection/intoxication in humans are commonly caused by bacteria such as Salmonella spp., Escherichia coli, Yersinia spp., Campylobacter spp., Listeria monocytogenes, and fungi (Aspergillus, Fusarium). The addition of probiotic cultures (bacterial strains Lactobacillus and Bifidobacterium and the yeast Saccharomyces cerevisiae var. boulardii) to food contributes primarily to food enrichment and obtaining a functional product, but also to food preservation. Reducing the number of viable pathogenic microorganisms and eliminating or neutralizing their toxins in food is achieved by probiotic-produced antimicrobial substances such as organic acids (lactic acid, acetic acid, propionic acid, phenylacetic acid, and phenyllactic acid), fatty acids (linoleic acid, butyric acid, caproic acid, and caprylic acid), aromatic compounds (diacetyl, acetaldehyde, reuterin), hydrogen peroxide, cyclic dipeptides, bacteriocins, and salivabactin. This review summarizes the basic facts on microbial contamination and preservation of food and the potential of different probiotic strains and their metabolites (postbiotics), including the mechanisms of their antimicrobial action against various foodborne pathogens. Literature data on this topic over the last three decades was searched in the PubMed, Scopus, and Google Scholar databases, systematically presented, and critically discussed, with particular attention to the advantages and disadvantages of using probiotics and postbiotics as food biopreservatives.

Vaccinium myrtillus L. (bilberry) leaves have traditionally been used to manage hyperglycaemia in folk medicine. The combination of plant polyphenols with dietary fibres such as inulin may offer enhanced metabolic benefits; however, their combined effects remain insufficiently characterized. This study aimed to evaluate the antihyperglycaemic effects of bilberry leaf extract (VME) and its inulin-enriched formulation (VMEI), and to investigate their potential as functional food components for managing type 2 diabetes. VME and VMEI were assessed using in vitro enzyme inhibition and an in vivo Caenorhabditis elegans model to evaluate toxicity. High-performance liquid chromatography (HPLC) was used to profile major compounds. A three-month dietary intervention was conducted in mice fed a high-fat, high-sucrose (HFHS) diet to examine the glucose-lowering effects of the extracts. HPLC analysis identified chlorogenic acid as the major constituent, followed by quercetin derivatives. VMEI exhibited stronger α-glucosidase inhibition than VME, indicating synergistic activity. Rutin and hyperoside showed the highest inhibitory activity against α-amylase and α-glucosidase, respectively. In C. elegans, VME displayed moderate toxicity at higher doses, and both extracts reduced locomotion. In the mouse model, both VME and VMEI significantly reduced blood glucose levels in HFHS-fed mice, with effects comparable to healthy control. VMEI showed more pronounced improvements, still not statistically significant. Overall, the combination of bilberry leaf polyphenols with inulin demonstrated enhanced in vitro enzyme inhibition, while in vivo findings indicate potential antihyperglycaemic effects that warrant further investigation. These results support the continued exploration of VMEI as a functional food candidate for metabolic health management.

The aim of this study was to evaluate the potential of minimally processed beetroot pomace (BP), obtained from an industrial juice producer selected as a case study, converted into a stable beetroot pomace flour (BPF) at an industrial scale level, for flour fortification, functional confectionery development, and dietary supplementation. It was characterized by a high dietary fiber content (~27 g/100 g) and a very low carbohydrate-to-fiber ratio (1.9). High level of total phenolics and flavonoids (14.1 ± 0.1 mg GAE/g and 1.43 ± 0.1 mg QE/g), betacyanins and betaxanthins (898 ± 54 and 960 ± 65 µg/g), as well as pronounced antioxidant (FRAP 31.5 ± 1.1 and DPPH 25.8 ± 2.9 µmol TE/g), anti-hyperglycemic and anti-inflammatory activity (27.3 ± 1.3% and 41.0 ± 3.4%) remained upon in vitro digestion. Replacing 14–28% of cereal and pseudo-cereal flour with BPF reduced the carbohydrate-to-fiber ratio to the recommended 10:1, while incorporation of 20% BPF into cookies reduced this ratio by 2.5-fold and the glycemic index from ~56 to ~30. Furthermore, long-term supplementation of standard and high-fat/high-sucrose diet with BPF (0.5% w/w) reduced feed efficiency by 1.7 and 2.6-fold respectively, and improved glucose tolerance in C57BL/6J mice. Findings show the effectiveness of the by-product in bridging the fiber intake gap and body weight regulation.