Smoking Impact on the Microbial Load of Clarias gariepinus

Abstract

Effects of different smoking methods on microbial load on freshly collected freshwater mud fish, Clarias gariepinus samples from Oyo State Fisheries Department, Ibadan in South-Western Nigeria was carried out. Seventy-two C. gariepinus (505 ± 0.45g and 25.5 ± 1.30cm) were collected and sorted into 4 groups. 10 fish samples from groups 1, 2 and 3 were subjected to cold smoking, hot smoking and oven drying methods respectively using group 4 as standard. Samples were tested for microbial loads in triplicate at the end of 24, 48 and 72 hrs. Some of the microbes identified were; Streptococcus faecium, Proteus vulgaricus, Pseudomonas aureginiosa, Bacillus cereus; Micrococcus acidiophilus, Aerobacter aerogenes, E. Coli, Streptococcus pyrogenes, Streptococcus lactis, Bacillus subtilis, Pedio cerevisiae, Sacchomyces Sp, Fusarium oxysporum, F. compacticum, Penicillium oxalicum, P. chrysogenum, Aspergillus tamari, A. niger, Cladosporum sphacrosporum, Aspergillus terreus and Rhizopus nigericans. Others are Pseadomonas, Alteromonas, Moraxella, Acinetobacter, Flavobacterium, Cytophaga, Vibrio, Aeromonoas, Staphylococcus aureus, Samonella faecuim, P. fragii. Microbial load for cold smoked products were 72%, 66% and 38%; hot smoked products had 61%, 32% and 08%; while oven-dried had 12%, 0% and 0% at 24, 48 and 12 hrs respectively. Positive correlation r = 0.94, 0.92 and 0.51 were observed between the microbial load processing methods – oven dried, hot-smoked and cold-smoked respectively. Cold smoked had 41.63% C.P and oven-dried had 25.73% C.P. Consumers had highest preference (40%) for hot smoked, 35% for oven dried and 25% for cold smoked products.

Key Words: Processing, storage, smoking, bacteria, Clarias gariepinus.