Effect of natural spices on the progression of microbial food spoilage in the steamed beans pudding, moin-moin

Abstract

Using a completely randomized block design, the progression of microbial food spoilage and the microbiological and sensory qualities of steamed cowpea paste (moin-moin) seasoned with onion, garlic, nutmeg and cinnamon was investigated. The total plate count was enumerated at approximately four hour intervals using Mueller-Hinton and Sabroaud dextrose agar for bacteria and fungal spoilage organisms respectively. Sensory evaluation was carried out using a 9-point hedonic scale. Results revealed no statistically significant difference in the progression of microbial spoilage. Eight bacterial species were isolated from the treatment samples as follows: Bacillus nealsoni, B. megaterium, B. pumilus, B marinus, Salimicrobium halophilum and Micrococcus varians. While 7 (seven) isolated fungi from the treatment samples are Gonatobotrys spp, Alternaria spp, Gymnoascus spp, Acremonium spp, Geotrichum spp, Oidiodendrum spp and Cladosporium spp. Untreated control and samples treated with nutmeg were preserved for the longest period of 23 hours. The present results show that moin-moin would spoil within 24 hours if kept at ambient temperature. The widely accepted reports of in-vitro anti-microbial effect of the spices was not observed in-vivo. Further
work is needed on increasing the shelf-life of moin-moin and other similar foods.

Keywords: Antimicrobial activity, in-vivo, flow diagram.