A Comparative Analysis of the Microbial Load of Two Drying Methods for the Preservation of Clam (Tegillarca granosa)

Abstract

Tegillarca granosa (clam) was preserved by different drying methods. The molluscan shellfish sample was smoked dried and oven dried to predict the most effective method of drying based on the microbiological quality, proximate composition and sensory evaluation of the shellfish sample. Total viable bacterial counts of Tegillarca granosa ranged from 2.45±1.94 - 0.19±.28 x106 cfu/g, Vibrio counts ranged from 3.88±3.32 - 0.00±0.00´104 cfu/g, Pseudomonas count ranged from 3.65±3.25 - 0.00±0.00´103 cfu/g. Salmonella ranged from 3.46±2.70 – 0.00±0.00´105 cfu/g. Shigella ranged from 3.68±2.70 – 0.00±0.00 ´ 105 cfu/g, Staphylococcus counts ranged from 3.67±2.81 – 1.19±2.13 ´ 104 cfu/g. Coliform counts ranged from 5.74±2.63 - 0.00±0.00´105 cfu/g,. Fungal counts ranged from 4.13±2.75 - 0.03±0.07´104 cfu/g. The bacteria isolated were Bacillus, Enterobacter, Escherichia coli, Klebsiella, Pseudomonas, Salmonella, Shigella, Staphylococcus and Vbrio. The fungi isolated were Aspergillus flavus, Aspergillus niger, Penicillium sp and Saccharomyces cerevisiae. Results obtained showed that clam contains unacceptable counts of bacteria and fungi, higher than the specified standard limits of 1.0´105 cfu/g for bacteria 1.0´102 cfu/g for coliform. Proximate composition showed that smoked dried clam is nutritionally richer than oven dried clam. Protein content, carbohydrate content, fat content and moisture content were higher in smoked dried clam than oven dried clam while crude fiber and ash content were higher in oven dried clam. Sensory evaluation to determine the degree of liking showed that the smoke-dried clam was more preferred than the oven dried clam. The result of the microbial analysis revealed that fresh clam had higher microbial load than smoked dried and oven dried clam. Preservation by drying was effective in reducing the microbial load from the shellfish samples. The smoked drying method was more effective in reducing the microbial load of the shellfish samples than the oven dried samples.