The term ‘toddy’ represents a group of different varieties of mild-alcoholic palm beverages of coastal and inland India, produced from the fresh saps of various palm trees through uncontrolled natural fermentation. In this study, we analysed the successional changes of microbial abundances and various physico-chemical parameters during natural fermentation (0 h to 48 h) of taal toddy, prepared from Palmyra palm, and khejur toddy, prepared from date palm of West Bengal and Jharkhand in India. Microorganisms from different successional levels were isolated and grouped using repetitive element sequence-based PCR (rep-PCR) technique and identified by the sequencing of 16S rRNA gene and D1-D2 region of 26S rRNA gene for bacteria and yeasts, respectively. Enterococcus faecalis, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei and yeast Saccharomyces cerevisiae were identified during natural fermentation of toddy. During the natural fermentation, the average pH and total sugar content in the samples of both taal and khejur toddy decreased, whereas a gradual rise was observed in the contents of acidity, total alcohol, total ester and total protein. Bio-active potential (presence of phenolics and flavonoids) of toddy was also analysed (0 h to 48 h), where contents of total phenolics, flavonoids and resulting anti-oxidant activity were found higher in the end-product than the fresh palm sap, indicating toddy as a functional low-alcoholic drink. Lastly, it can be concluded that the inter-variable dynamics and microbial interrelation, which in turn depend on a number of local factors, regulate the overall fermentation dynamics and determine the product quality.

Sixteen long-ripened, high-quality Cabrales cheeses from independent producers underwent a comprehensive biochemical and microbiological characterisation. Significant variations in total microbial counts and specific microbial groups were observed among the cheeses. A metataxonomic analysis identified 249 prokaryotic amplicon sequence variants (ASVs) and 99 eukaryotic ASVs, respectively, which were classified into 52 prokaryotic and 43 eukaryotic species. The predominant species included bacteria of the genera Tetragenococcus, Lactococcus (of which Lactococcus lactis was used as a starter), and Staphylococcus, followed by Brevibacterium and Corynebacterium species. The starter mould Penicillium roqueforti was highly abundant in all cheeses; Debaryomyces hansenii, Geotrichum candidum, and Kluyveromyces spp. constituted the subdominant fungal populations. Glutamic acid (≈20 mg g⁻¹) was the most abundant free amino acid in all samples, followed by lysine, leucine, and valine (≈10–13 mg g⁻¹). Moderate-to-high amounts of the biogenic amines tyramine and ornithine were detected. A large variation between cheeses of the main organic acids (lactic, acetic, or butyric) was detected. Differences between samples were also observed for the majority volatile compounds, which included organic acids, alcohols, esters, and ketones. Positive and negative correlations between bacterial and fungal species were detected, as well as between microbial populations and key biochemical markers. Among the latter, Tetragenococcus halophilus correlated positively with ethyl caprylate and hexanoic acid, and Loigolactobacillus rennini correlated positively with γ-aminobutyric acid. Conversely, Staphylococcus equorum showed a strong negative correlation with ethyl caprylate and capric acid. These microbial and biochemical insights enabled us to propose a microbiota-based starter culture comprising prokaryotic and eukaryotic components to enhance Cabrales cheese quality.

1. Fermented and Functional foods (F&FFs) that confer food safety and security have been integral to human gastronomy and culinary practices for millennia and are key to a sustainable future in the...