Q. Explain Spoilage by yeasts?
Yeasts dominate in the spoilage of fruit products which contain high acid content due to their ability to tolerate high acid environment. Yeasts are osmophiles but they can tolerate only high sugar environment but not salt. They also have the ability to groq anaerobically and have low nutritional requirements coupled with the ability to synthesize the nutrients required for growth and survival.
Among the types of yeasts, the ascospore-forming and heat-resistant organisms like Saccharomyces cerevistae and S. chevalieri are found responsible for the spoilage in canned fruit products. The growth of yeast in a product results in the .formation of CO2, development of turbidity, clumping and flocculation (forming wooly cloudlike aggregations).