Effect of different processing methods on the meat of <i>Tympanotonus fuscatus</i>

Abstract

50kg periwinkle was purchased from Oyingbo market in Lagos State, South-west of Nigeria. The bag contained a mixture of two species namely; Tympanotonus fuscatus var fuscatus and Tympanotonus fuscatus var radula. They were processed to remove the meat from the shell. The fresh periwinkle meats were dried in the multipurpose produce dryer designed by Nigerian Stored Product Research Institute’s (NSPRI) for 15hrs at a temperature of 60^oC (Sample A). Fresh and dry periwinkle meats were bought from Iddo Market in Lagos to serve as control (Sample B). The moisture contents of fresh and dry Sample A were 81.20% and 6.52% respectively while that of fresh and dry Sample B were 79.60% and 10.45%. Also, the results of microbial analysis of fresh and dry periwinkle (Sample A) showed sample count of 5.8cfu/g and1.2x10^-1cfu/g respectively. No pathogenic organisms (E.coli, Salmonella spp.) and fungi were isolated. The microbial analysis carried out on Sample B showed high microbial load (Fresh: 6×10³cfu/g, Dry: 1.2×10³cfu/g). Statistical analysis revealed a significant difference (p< 0.05) for microbial loads in both fresh and dried samples between Samples A and B while there was no  significant difference in the moisture contents of the two samples. Ten per cent (10%) of foreign matters was found in sample B; it also appeared brownish and rough with a repulsive odour. The heavy metals analysis for sample A and B revealed that the amounts present were all within safe limits except for copper at  35.61mg/kg^-1 in sample B. This is against its safe limit of 1.20 mg/kg^-1 recommended by European Union (EU) standards on fish and other sea foods. Based on the findings from this research work, members of the public should be educated on the importance of proper processing methods on the quality of periwinkle meat.

Key words: periwinkle, processing, nutritive value, heavy metals, dry.