The predominance of Penicillium, Mucor, and Yarrowia among spoilage fungi in cultured dairy products produced by 3 manufacturers, as revealed by amplicon sequencing

Summary

Researchers identified which molds and yeasts cause yogurt and other cultured dairy products to spoil by analyzing 200 contaminated samples from 3 manufacturers. Three types of fungi—Penicillium, Mucor, and Yarrowia—were responsible for over 70% of the spoilage cases. Interestingly, these fungi were still found in products containing preservatives, suggesting they can resist or break down common food preservatives. The study shows that using DNA sequencing to identify these organisms is more accurate and helpful than traditional methods, allowing dairy manufacturers to develop better strategies to prevent contamination.

Background

Fungal spoilage in cultured dairy products causes consumer dissatisfaction, food waste, and financial losses globally. Fungi commonly contaminate cultured dairy products after pasteurization, leading to changes in texture, odor, and appearance. Accurate identification of spoilage fungi is essential for producers to develop targeted elimination strategies.

Objective

To identify and characterize fungi responsible for spoilage in cultured dairy products by amplifying the ITS1-5.8S-ITS2 ribosomal DNA region. The study aimed to identify fungi in spoiled cultured dairy products and assess sequence diversity of fungi related to cultured dairy products.

Results

The 3 most common genera identified were Penicillium (46.5%), Mucor (15%), and Yarrowia (12.5%), accounting for over 70% of all isolates. A total of 24 genera were identified across 3 phyla: Ascomycota, Basidiomycota, and Mucoromycota. Penicillium remained the most frequently isolated genus regardless of preservative inclusion, while sequence diversity analysis showed variation in SNP differences among genera.

Conclusion

Penicillium, Mucor, and Yarrowia are the predominant spoilage fungi in cultured dairy products, even in products containing protective cultures or potassium sorbate. ITS amplicon sequencing provides accurate identification superior to morphology alone and can guide producers in developing targeted elimination strategies. The ability of certain fungi to resist or metabolize preservatives contributes to their prevalence in dairy products.
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