Detection of Zygosaccharomyces rouxii and Candida tropicalis in a High-Sugar Medium by a Metal Oxide Sensor-Based Electronic Nose and Comparison with Test Panel Evaluation

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

The use of yeasts as starter cultures was boosted with the emergence of large-scale fermentations in the 20th century. Since then, Saccharomyces cerevisiae has been the most common and widely used microorganism in the food industry. However, Candida 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 Candida is sometimes performed to obtain the best performing strains to enhance specific features. Some commonly selected species include C. pulcherrima (teleomorph Metschnikowia pulcherrima) (wine), C. parapsilosis (teleomorph Monilia parapsilosis) (coffee), C. famata (teleomorph Debaryomyces hansenii) (cheese), and C. zeylanoides (teleomorph Kurtzmaniella zeylanoides) and C. norvegensis (teleomorph Pichia norvegensis) (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 Candida species are opportunistic human pathogens, with important clinical relevance. Here, the physiology and metabolism of Candida species are addressed, initially emphasizing their clinical aspects and potential pathogenicity. Then, Candida species used in food fermentations and their functional roles are reported. We recommended that Candida 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.

Zygosaccharomyces rouxii: Control Strategies and Applications in Food and Winemaking

The genus Zygosaccharomyces is generally associated to wine spoilage in the winemaking industry, since a contamination with strains of this species may produce re-fermentation and CO2 production in sweet wines. At the same time, this capacity might be useful for sparkling wines production, since this species may grow under restrictive conditions, such as high ethanol, low oxygen, and harsh osmotic conditions. The spoilage activity of this genus is also found in fruit juices, soft drinks, salad dressings, and other food products, producing besides package expansion due to gas production, non-desired compounds such as ethanol and esters. Despite these drawbacks, Zygosaccharomyces spp. produces high ethanol and acetoin content in wines and may play an important role as non-Saccharomyces yeasts in differentiated wine products. Control strategies, such as the use of antimicrobial peptides like Lactoferricin B (Lfcin B), the use of dimethyl dicarbonate (DMDC) or non-thermal sterilization techniques may control this spoilage genus in the food industry.

Recognition of osmotolerant yeast spoilage in kiwi juices by near-infrared spectroscopy coupled with chemometrics and wavelength selection

The study developed a NIR-SVM model for accurate recognition of osmotolerant yeasts in kiwi juice for the first time.

Wash-free colorimetric homogeneous immunoassay for Zygosaccharomyces rouxii

A rapid and convenient AuNP-based method for detecting large microbes was developed.