Yeasts and moulds contaminants of food ice cubes and their survival in different drinks.

AIMS

To evaluate the levels of unicellular and filamentous fungi in ice cubes produced at different levels and to determine their survival in alcoholic beverages and soft drinks.

METHODS AND RESULTS

Sixty samples of ice cubes collected from home level (HL) productions, bars and pubs (BP) and industrial manufacturing plants (MP) were investigated for the presence and cell density of yeasts and moulds. Moulds were detected in almost all samples, while yeasts developed from the majority of HL and MP samples. Representative colonies of microfungi were subjected to phenotypic and genotypic characterization. The identification was carried out by restriction fragment length polymorphism (RFLP) analysis of the region spanning the internal transcribed spacers (ITS1 and ITS2) and the 5·8S rRNA gene. The process of yeast identification was concluded by sequencing the D1/D2 region of the 26S rRNA gene. The fungal biodiversity associated with food ice was represented by nine yeast and nine mould species. Strains belonging to Candida parapsilosis and Cryptococcus curvatus, both opportunistic human pathogens, and Penicillium glabrum, an ubiquitous mould in the ice samples analysed, were selected to evaluate the effectiveness of the ice cubes to transfer pathogenic microfungi to consumers, after addition to alcoholic beverages and soft drinks. All strains retained their viability.

CONCLUSIONS

The survival test indicated that the most common mode of consumption of ice cubes, through its direct addition to drinks and beverages, did not reduce the viability of microfungi.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study evidenced the presence of microfungi in food ice and ascertained their survival in soft drinks and alcoholic beverages.