Yeast diversity in chicken meat products: Occurrence, hazards, and quality implications

Food spoilage poses a significant challenge for both the food industry and consumers, rendering products unfit for consumption and leading to substantial food waste and economic losses. This study aimed to assess the occurrence of yeasts in five distinct types of raw meat poultry products (feet, gizzard, heart, liver, and neck) under two packaging conditions, providing insights into potential spoilage agents. For this purpose, one hundred poultry samples were collected from retail markets and supermarkets in Portugal to evaluate the total yeast count and assess the profiles and diversity of mycological species. Species identification was based on culture morphology, microscopic examination, biochemical profile, and Matrix-assisted laser desorption/ionizationtime of flight mass spectrometry (MALDI-TOF-MS). Results showed that local markets and unpacked samples exhibited significantly higher total yeast counts, particularly in heart, gizzard, and liver samples. Yeasts were isolated from 96% (95% CI: 90-98%) of the samples, with an average count of 3.13±0.96 log colony-forming units (CFU)/g. All yeast isolates belonged to seven different genera, i.e., Candida, Debaryomyces, Malassezia, Zygosaccharomyces, Rhodotorula, Yarrowia, and Cryptococcus, which are commonly found in food and environmental samples. The yeast species identified included Candida zeylanoides (26.83%), C. ciferrii (2.44%), Debaryomyces hansenii (19.51%), Zygosaccharomyces sp. (7.34%), Rhodotorula mucilaginosa (9.76%), Cryptococcus laurentii (4.88%), Malassezia pachydermatis (2.44%), Yarrowia lipolytica (9.76%) and Yarrowia galli (2.44%). A yeast-like fungus, Aureobasidium pullulans, was also identified in one unpacked sample of feet obtained from the retail market, potentially introduced through contact with contaminated surfaces or handling equipment. Recognizing the prevalence and variety of yeasts in food is crucial for developing effective strategies to mitigate these spoilage agents and ensure food safety and suitability. In conclusion, this study provides valuable insights into the occurrence of yeasts in fresh chicken meat products, highlighting the importance of developing effective strategies to mitigate yeast spoilage throughout the poultry supply chain. Furthermore, identifying emerging health concerns associated with yeasts, such as Y. galli and A. pullulans, which are implicated in human infections, highlights the critical need for comprehensive contamination control and monitoring practices to ensure food safety and public health.