Schizosaccharomycetaceae

The Schizosaccharomycetaceae family consists of fission yeasts, which are unicellular fungi that reproduce by binary fission rather than budding. While they are industrially useful for fermentation, in an agricultural context, they function as opportunistic pathogens capable of spoiling fruit and vegetable products post-harvest.

The type of disease caused is classified as microbiological spoilage or secondary decay. These pathogens act as saprotrophs, colonizing plant tissues that have already been weakened or structurally damaged, subsequently accelerating the breakdown of cellular integrity through vigorous fermentation processes.

Key crops susceptible to these fungi include grapes, stone fruits like peaches and plums, and various berries. The pathogen is particularly dangerous in high-sugar environments, making both fresh produce and processed goods, such as fruit juices and concentrates, highly vulnerable during storage and transport.

The symptoms of infection are distinct and include a sour, fermented smell, softening of the fruit flesh, and the formation of slimy patches on the skin. In advanced stages, one can observe visible fermentation bubbles and a noticeable change in the internal chemistry, rendering the produce unfit for consumption.

The development and spread of these yeasts are facilitated by high moisture levels, warm temperatures (20–30°C), and the presence of accessible sugars. The entry points are almost exclusively mechanical injuries caused by insect feeding, hail damage, or poor handling during harvest, which expose the nutrient-rich interior of the fruit.

Management and preventative strategies include:

• Implementing integrated pest management (IPM) to minimize fruit skin damage by insects.
• Ensuring strict sanitation protocols during harvesting to prevent cross-contamination.
• Rapid cooling and cold chain management to keep storage temperatures low, inhibiting yeast metabolism.
• Proper sorting of fruits to remove damaged individuals before long-term storage.