Effects on Quality of Application of Two Antagonistic Yeasts on Plums (Prunus salicina) During Postharvest Cold Storage

Plums are climacteric fruits with a short postharvest shelf-life, which makes them highly susceptible to spoilage by moulds and pathogens. Biological control using antagonistic yeasts offers a promising approach to extend shelf-life by inhibiting fungal growth. This study evaluated the effects of two yeast strains, <i>Hanseniaspora uvarum</i> L793 and <i>Metschnikowia pulcherrima</i> L672, on the quality of 'Larry Ann' Japanese plums during cold storage. Plums were divided into three batches: two treated by immersion in yeast suspensions (10⁸ cells mL^-1) and one untreated control. Quality parameters assessed over 12 weeks at 1 °C included weight loss, decay index, microbial counts, yeast colonisation, skin and flesh colour, texture, pH, titratable acidity, total soluble solids, and ripening index, with evaluations every week. <i>M. pulcherrima</i> L672 showed strong colonisation and persistence on the plum surface, significantly reducing skin damage and mould incidence. In contrast, <i>H. uvarum</i> L793 initially colonised well but declined over time, being replaced by native yeasts such as <i>Aureobasidium</i> spp. Both treatments maintained the physicochemical and organoleptic quality of the plums throughout storage. However, <i>M. pulcherrima</i> L672 was more effective in suppressing fungal growth and preserving fruit integrity. These findings suggest that <i>M. pulcherrima</i> L672 is a promising biocontrol agent for prolonging the shelf-life of Japanese plums during cold storage, maintaining their commercial quality for up to three months.