What Is Candida Doing in My Food? A Review and Safety Alert on Its Use as Starter Cultures in Fermented Foods

Abstract

The use of yeasts as starter cultures was boosted with the emergence of large-scale fermentations in the 20th century. Since then, <i>Saccharomyces cerevisiae</i> has been the most common and widely used microorganism in the food industry. However, <i>Candida</i> species have also been used as an adjuvant in cheese production or as starters for coffee, cocoa, vegetable, meat, beer, and wine fermentations. A thorough screening of candidate <i>Candida</i> is sometimes performed to obtain the best performing strains to enhance specific features. Some commonly selected species include <i>C. pulcherrima</i> (teleomorph <i>Metschnikowia pulcherrima</i>) (wine), <i>C. parapsilosis</i> (teleomorph <i>Monilia parapsilosis</i>) (coffee), <i>C. famata</i> (teleomorph <i>Debaryomyces hansenii</i>) (cheese), and <i>C. zeylanoides</i> (teleomorph <i>Kurtzmaniella zeylanoides</i>) and <i>C. norvegensis</i> (teleomorph <i>Pichia norvegensis</i>) (cocoa). These species are associated with the production of key metabolites (food aroma formation) and different enzymes. However, safety-associated selection criteria are often neglected. It is widely known that some <i>Candida</i> species are opportunistic human pathogens, with important clinical relevance. Here, the physiology and metabolism of <i>Candida</i> species are addressed, initially emphasizing their clinical aspects and potential pathogenicity. Then, <i>Candida</i> species used in food fermentations and their functional roles are reported. We recommended that <i>Candida</i> not be used as food cultures if safety assessments are not performed. Some safety features are highlighted to help researchers choose methods and selection criteria.