Effect of Sodium Chloride Curing on the Microbial Quality of Fresh Water and Marine Periwinkle Species in Nigeria

Studies on the effect of sodium chloride curing on the microbial quality of fresh water and marine species of African periwinkles (Pachymelania aurita and Tympanotonus fuscatus) from Itu market, Itu Local Government Area, Akwa Ibom State, Nigeria were conducted. A standard solution of sodium chloride was prepared in the ratio; 1:10 w/v. The cleaned periwinkle species were sorted manually and cured at different concentrations (0%, 5%, 10%, 15%, and 20%). Data collected were analyzed and tested at (P<0.05) level of significance, using analysis of variance (ANOVA). The Total Heterotrophic Bacterial Load (THBC) ranged from (0.8x102 – 2.1x103 CFU/g) for fresh water periwinkle and (0.9x102 – 1.5x103 CFU/g) for marine periwinkle. In both species, the uncured samples recorded the highest THBC. The fresh water periwinkle recorded higher THBC than marine periwinkle. The Staphylococcus count recorded was (1.1x103 CFU/g) for uncured freshwater periwinkle, and (1.0x102 CFU/g) for uncured marine periwinkle. The fecal count ranged from (1x102 – 3x102 CFU/g) and (1x102 – 2x102 CFU/g) for fresh water and marine periwinkle, respectively. The results of the microbial analysis showed that the uncured fresh periwinkles had higher microbial load than the cured periwinkles. However, the microbial load observed in the study was not higher than (1x105 CFU/g) recommended by USFDA as maximum safety limit. The viable cell count at 600 nm (x106) detected by spectrophotometer revealed a significant reduction with increased concentration of sodium chloride from (0.682, 0.954) to (0.007, 0.006) nm (x106) for fresh water and marine periwinkle, respectively. The study showed that preservation of periwinkles by curing could be an effective approach to curbing microbial spoilage, enhancing shelf life and nutritional quality.