Incidence of pathogenic psychrotrophs in ice creams sold in some retail outlets in Mumbai, India

With a view to determine the microbial quality of ice creams, 30 samples of commercial brands of three flavours sold in the `openʹ and `packaged, (cone, cup)ʹ forms were analyzed for their total bacterial counts (TBC), yeast and mold counts (YMC), coliforms and pathogenic psychrotrophs; Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Yersinia enterocolitica and Salmonella spp. In general in both the types of ice creams bacterial load (2.3 × 104–8.5 × 106 cfu/ml) was higher; particularly coliform levels were 10–100 fold higher (3.0 × 102–5.8 × 104 cfu/ml) than the safety limits prescribed by Indian Standards Institute (ISI). Staph. aureus was detected in both the types of ice creams but occurrence of B. cereus was more frequent in open samples (40%) than in packed ones (26.6%). Salmonella was not detected in any of the 30 samples tested. While 53% of the packed and 100% of the open ice creams exhibited Listeria contamination, Yersinia were detected in 33% of packed and 40% of open ones. L. monocytogenes and/or Y. enterocolitica was detected only in one of the open ice cream samples. Growth profile of Y. enterocolitica 5692 and L. monocytogenes 036 at simulated temperature abuse conditions during commercial frozen storage showed that after 10 days L. monocytogenes could grow to >1 log and 1 log cycle at 8–10°C and 2–4°C, respectively and Y. enterocolitica grew 2 log cycles at both the temperatures. Results are discussed in the context of present microbiological specifications and the need for its implementation by regulatory agencies to ward off possible health hazards arising from pathogens