Assessment of microbial quality of ice and source water used for preservation of fish quality in the southern province of Sri Lanka

The present study assessed the microbial quality of manufactured ice and the source water used for commercial fish post-harvest handling in the Southern Province of Sri Lanka. Source water and ice samples were collected from 15 ice plants between October 2021 and October 2022 and immediately analyzed for aerobic plate count (APC) at 37⁰C, total coliforms, faecal coliforms, Escherichia coli (E. coli) and Salmonella species using SLSI protocols. The information on workplace sanitation was obtained through a questionnaire survey.  Source water and ice contained APC in the range of 6.2x10¹ - 6.9x10⁴ and 4.1x10¹ - 1.9x10⁴ CFU/mL, respectively. Sixty-seven per cent of ice samples and sixty per cent of water samples collected exceeded the SLS limit for APC (100 CFU/mL). Faecal coliform counts in source water and ice ranged between 4 and 783 MPN/100 mL and 4 and 242 MPN/100 mL, respectively. Ninety three percent of source water and ice samples were contaminated with E. coli, and the counts varied between 0 and 145 MPN/100 mL and 0 and 105 MPN/100 mL, respectively. No Salmonella contamination was observed in water or ice samples. Of the three districts in the province, Matara showed the lowest count for the tested parameters. Source water used for ice production was a mixture of different water sources. Results revealed that the workplace sanitary conditions were significantly correlated with the microbial quality of ice (p<0.05). An urgent need is required to improve the sanitary conditions in ice plants of the Southern province to avoid faecal bacteria contamination in the production line of ice plants from source water extraction. Implementing sanitary standards and operational procedures in manufacturing plants is also recommended.