Screening and Characterization of the Diversity of Food Microorganisms and Their Metabolites

Food is rarely kept in a sterile environment and the composition of microbial associations found in various foodstuffs is widely varied. Microorganisms in food usually originate from the natural microbiota of raw materials and the surrounding environments. Whether a species prevails depends upon its ability to adapt to intrinsic factors associated with foods, such as nutrient content; pH; water activity; oxidation–reduction potential; and antimicrobial properties, with various extrinsic factors playing a role, including temperature, relative humidity, atmosphere, and ambient pressure. Any change to these parameters may cause changes in the present microbial consortia. Therefore, it is important to identify which microbial consortia will thrive in particular foods and conditions. While active, microorganisms undergo many complex mechanisms that affect food quality and safety. Most beneficial food microorganisms belong to lactic acid bacteria and yeasts. Pathogenic and spoilage bacteria are usually Gram-negative, although there are some Gram-positive ones, such as Listeria monocytogenes, Clostridium botulinum, and C. perfringens. Some may merely cause spoilage, while others may be related to foodborne illnesses.Thanks to all the authors and reviewers for their excellent contributions to this Special Issue. Additional thanks to the Microorganisms Editorial Office for their professional assistance and continuous support. The authors of this editorial article would also like to acknowledge COST Action 18101 SOURDOMICS—Sourdough biotechnology network towards novel, healthier, and sustainable food and bioprocesses (https://sourdomics.com/; https://www.cost.eu/actions/CA18101/, accessed on 18 March 2023)—where authors B.K. and S.K.V. are members of the working groups 2, 6, and 8; author M.T. is member of the working groups 2 and 3 and author J.M.R. is the Chair and Grant Holder Scientific Representative and is supported by COST (European Co-operation in Science and Technology) (https://www.cost.eu/, accessed on 18 March 2023). COST is a funding agency for research and innovation networks. Author J.M.R. also acknowledges the Universidade Católica Portuguesa, CBQF-Centro de Biotecnologia e Química Fina—Laboratório Associado, Escola Superior de Biotecnologia, Porto, Portugal, as well as the support made by LA/P/0045/2020 (ALiCE) and UIDB/00511/2020-UIDP/00511/2020 (LEPABE) funded by national funds through FCT/MCTES (PIDDAC)