Effect of Moringa oleifera marinade on microbial stability of smoke-dried African Catfish (Clarias gariepinus)

Abstract

The study examined the antimicrobial effect of Moringa oleifera marinade on smoke-dried catfish stored at ambient temperature (37±20C) for two months. The experimental treatments are the control, 1%, 2% and 3% (w/v) Moringa oleifera Marinade (MOM) and 5% Brine (w/v) solutions. Seventy-five fishes of average weight of 260±8g were gutted, washed and randomly assigned to the treatments. Thereafter, the fishes were soaked in the treatments for 2 hours and later hot smoked for 12hours. After smoking, the fishes were stored in netted boxes and placed on laboratory shelves for two months. Microbial counts were conducted at 7-day interval while biochemical tests were conducted on the 8th week. Seven bacterial species namely; Staphylococcus sp, Bacillus sp, Klebsiella sp, Corynebacterium sp, Pseudomonas sp, Escherichia coli and streptococcus sp and six fungal species namely; Penicillium italicum, Cladosporium sp, Neurospora crassa, Candida sp, Aspergillus niger and Saccharomyces cerevisiae were observed in the study. There was a general increase in microbial load as storage progressed. However, the increment was pronounced in the control and brine treated fish samples. In all levels of MOM and 5% Brine, there was decrease in the bacterial and fungal counts as compared with the control samples. 3% MOM exhibited the highest antibacterial potency while 5% Brine exhibited the highest antifungal potency. Moringa oleifera marinade could be use to protect stored smoke-dried catfish from microbial spoilage thus limiting economic loss and possible heath risk to consumers.

Key words: Moringa, marinade, bacteria, fungi, catfish, smoke-dried