Abstract

The aim of this study was to evaluate the microbiological and preservative effect of potassium sorbate and natural agent (potassium aluminium sulphate) also known as alum, on periwinkle during ambient temperature storage. Periwinkle meat was shucked and prepared aseptically and preservatives; potassium sorbate 0.1% (w/v), potassium aluminium sulphate 1% (w/v) and combination of both preservatives were separately applied on the sample. The samples were stored at ambient temperature and microbial analysis was carried out for 2 days. The total heterotrophic bacterial count of the control sample from the initial time to day 2 had the highest value of 5.1 ±0.0×10² to 2.24±0.1×10⁷ CFU/g while the total count of alum treatment was the least 3.4±0.01×10² to 8.7±0.03×10³ CFU/g. The highest count of total coliform for control sample was 6.3±0.01×10⁴ to 1.92±0.01×10⁶ (initial time to day 2) while the least count of total coliform with the treatment with Alum was 2.1±0.1×10² to 1.92±0.01×10³ CFU/g. The count of Salmonella and Shigella for the treatment with Alum had the least value of 1.04±0.02×10³ CFU/g while the control sample had the highest value of 8.4±0.02×10⁴ to 1.53±0.01×10⁵ CFU/g. The least count of E. coli (3.6 ±0.1×10³ CFU/g) was in the sample treated with Alum preservative while the control sample had the highest count of 9.4±0.01×10³ to 1.24±0.1×10⁵ CFU/g from the initial time to day 2. The fungal count of the samples was recorded only on day 2 (no growth on the initial time and day 1) and the Alum preservative had the least value of 3.3±0.02×10² CFU/g and the control had the highest count, 7.2±0.01×10⁴ CFU/g. The bacteria isolated and identified through biochemical test were Escherichia coli, and species of Micrococcus, Staphylococcus, Enterobacter, Pseudomonas, Salmonella, Shigella, Proteus, Citrobacter, Alcaligenes and Bacillus. While fungi were Candida, Aspergillus niger and Penicillium sp. Some bacteria identified molecularly with ascension numbers were Alcaligenes faecalis, MN833516, Pseudomonas aeruginosa, MN985328, Escherichia coli, MN396566 and Bacillus niacin, JF496375. From the study, it can be recommended that Potassium aluminium sulphate (Alum) could be applied in the preservation of shucked periwinkle meat to improve the shelf-life and microbial safety as it produced better attribute compared to other preservative treatments.