Microbial Interactions within the Cheese Ecosystem and Their Application to Improve Quality and Safety

Abstract

The cheese microbiota comprises a consortium of prokaryotic, eukaryotic and viral populations, among which lactic acid bacteria (LAB) are majority components with a prominent role during manufacturing and ripening. The assortment, numbers and proportions of LAB and other microbial biotypes making up the microbiota of cheese are affected by a range of biotic and abiotic factors. Cooperative and competitive interactions between distinct members of the microbiota may occur, with rheological, organoleptic and safety implications for ripened cheese. However, the mechanistic details of these interactions, and their functional consequences, are largely unknown. Acquiring such knowledge is important if we are to predict when fermentations will be successful and understand the causes of technological failures. The experimental use of “synthetic” microbial communities might help throw light on the dynamics of different cheese microbiota components and the interplay between them. Although synthetic communities cannot reproduce entirely the natural microbial diversity in cheese, they could help reveal basic principles governing the interactions between microbial types and perhaps allow multi-species microbial communities to be developed as functional starters. By occupying the whole ecosystem taxonomically and functionally, microbiota-based cultures might be expected to be more resilient and efficient than conventional starters in the development of unique sensorial properties.

Microbial association networks in cheese: a meta-analysis

“…Even if, ultimately, co-culturing in the laboratory and/or in appropriate model systems is the only way to obtain in-depth knowledge on the nature of interactions (Cosetta and Wolfe, 2019;D'Souza et al, 2018;Wolfe et al, 2014), the wealth of data provided by metataxonomic, metagenomic and metabolomics approaches provides ample opportunity to mine for microbial association networks and metabolic networks (Layeghifard et al, 2017;Liu et al, 2020;Röttjers and Faust, 2018). Microbial interactions in cheese and in other fermented foods have been the subject of recent comprehensive reviews (Blaya et al, 2017;Canon et al, 2020;Gobbetti et al, 2018;Mayo et al, 2021). A schematic, and possibly oversimplified representation of interactions (parasitism, commensalism, amensalism, competition, protocooperation) occurring in an idealized surface ripened cheese is shown in Figure 1, with some of the interactions described in detail in section 1.3 and Table 1.…”

Variability of the microbiota in traditional Caciocavallo, Scamorza and Caciotta cheeses manufactured with raw milk and natural cultures

“…Yeasts and moulds were found at high levels in a Scamorza cheese lot. Since some yeast species, such as Geotrichum candidum and Yarrowia lipolytica, are involved in the production of aromatic compounds (Mayo et al 2021), the possible influence of these microorganisms on the organoleptic properties of these traditional cheeses should be elucidated.…”

“…Use of autochthonous mixed cultures composed of LAB strains isolated in this study could improve safety, even if these are devoid of bacteriocin production genes. Indeed, other mechanisms of inhibition of unwanted microorganisms by LAB can take place, such as competition for nutrients and formation of undissociated organic acids, hydrogen peroxide and fatty acids (Mayo et al 2021). To obtain those cultures, the next step is testing isolated SLAB and NSLAB multiple strain associations for their capacity to grow in co-cultures.…”

“…The natural LAB population can also include potential probiotics that are able to survive in the gastrointestinal tract (GIT), as suggested by a study on a traditional Pasta Filata fresh cheese (Amadoro et al 2018). Starter LAB (SLAB) species comprise fast acidifying microorganisms, while nonstarter LAB (NSLAB) are mainly responsible for the biochemical processes in cheese during the maturation stage that lead to flavour development and aroma formation (Mayo et al 2021).…”

“…Starter LAB (SLAB) species comprise fast acidifying microorganisms, while nonstarter LAB (NSLAB) are mainly responsible for the biochemical processes in cheese during the maturation stage that lead to flavour development and aroma formation (Mayo et al . 2021).…”