RT Journal Article T1 Assessment of the Factors Contributing to the Growth or Spoilage of Meyerozyma guilliermondii in Organic Yogurt: Comparison of Methods for Strain Differentiation A1 Wrent, Petra A1 Rivas, Eva María A1 Gil de Prado, Elena A1 Martínez Peinado, José A1 Siloniz Jiménez, María Isabel de AB In this work we analyze the spoiling potential of Meyerozyma guilliermondii in yogurt. The analysis was based on contaminated samples sent to us by an industrial laboratory over two years. All the plain and fruit yogurt packages were heavily contaminated by yeasts, but only the last ones, containing fermentable sugars besides lactose, were spoiled by gas swelling. These strains were unable to grow and ferment lactose (as the type strain); they did grow on lactate plus galactose, fermented glucose and sucrose, and galactose (weakly), but did not compete with lactic acid bacteria for lactose. This enables them to grow in any yogurt, although only those with added jam were spoiled due to the fermentation of the fruit sugars. Fermentation, but not growth, was strongly inhibited at 8 °C. In consequence, in plain yogurt as well as in any yogurt maintained at low temperature, yeast contamination would not be detected by the consumer. The risk could be enhanced because the species has been proposed for biological control of fungal infections in organic agriculture. The combination of the IGS PCR-RFLP (amplification of the intergenic spacer region of rDNA followed by restriction fragment length polymorphism analysis) method and mitochondrial DNA-RFLP makes a good tool to trace and control the contamination by M. guilliermondii. PB MDPI SN 2076-2607 YR 2015 FD 2015-09 LK https://hdl.handle.net/20.500.14352/24304 UL https://hdl.handle.net/20.500.14352/24304 LA eng NO Universidad Complutense de Madrid y Banco de Santander NO Ministerio de Economía y Competitividad (España) DS Docta Complutense RD 9 abr 2025