Microbiological quality of artisanal ice cream

In the course of the years 1990 and 1991, 396 samples of artisanal ice-cream had been collected from different ice-cream shops in Udine and province and analysed. All tested flavours contained aerobic germs, coliforms, Enterococci and yeasts in different quantities. In the analysed samples neither Salmonellae spp., nor Listeria monocytogenes nor Staphylococcus aureus were detected. Numerous species of coliforms and yeasts were randomly isolated and identified. The statistical analysis, used to compare the variables (flavour, month, year), showed significant differences among the samples analysed in the two years. In September, the means of the total aerobic count were significantly different from the ones of July and of August. No significant differences were noted in the means of coliforms, total aerobic counts and yeasts in the different flavours. The techniques for recovery of freeze-stressed coliforms in artificially contaminated samples of ice-cream showed that the three techniques, which use both selective and non-selective mediums, are better than those ones, which use only selective mediums. Lastly, with regard at the coliform values, the ice-creams tested have small-medium quality. In fact 26% of the ice-creams cannot be sealed, according to the Italian Ministry Ordinance (October 11, 1978).