Assessment of microbiological safety of tiger nuts (Cyperus esculentus L.) in the Cape Coast Metropolis of Ghana

Abstract

The microbiological safety of tiger nut (Cyperus esculentus L.), a popular tuber eaten in the fresh uncooked state in Ghana was assessed from three major markets in the Cape Coast Municipality to ascertain their microbiological safety in relation to bacterial contamination. A study of 24 samples of 8 each from the markets divided into two batches were analyzed by surface-washing in Phosphate Buffered Water (PBS) only and PBS plus 1% Sodium hypochlorite. Serial dilutions were made and required volumes (0.1ml) of test samples were dispensed separately into sterile Petri dishes and pour plated with Plate Count Agar (PCA) for enumeration of colonies. MacConkey and Uriselect agars were used for enteric bacteria and species identifications. Mean Total Viable Count (TVC), Mesophilic Aerophilic Count (MAC), and Coliform Count (CC) on PCA using PBS only ranged between 2.54 ×10 5 - 8.22×10 5 ;1.87×10 5-5.44×10 5 and 9.44×10 2 - 3.32×10 3 CFU/g respectively whilst that of PBS plus 1% Sodium hypochlorite ranged between 1.51×10 2 -1.35×10 3 ; 2.52×10 3 -1.06×10 3 and 4.86×10 1- 8.69×10 1 CFU/g respectively. There was marked significant differences p-(0.0319; 0.0267; and 0.0104) between PBS only and PBS plus 1% Sodium hypochlorite for TVC, MAC and CC respectively. Seven different bacteria species isolated were made up of Bacillus spp. And Escherichia coli (18.9%) each; Enteroccoccus spp. (16.2%); Pseudononas aeruginosa and Staphylococcus aureus (13.5%) each, Streptococcus spp. (10.8%) and Enterobacter cloacae (8.1%). This study looks at the levels and nature of microbial contaminations of tiger nut retailed in the Cape Coast Metropolis, and the possible means of reducing such contamination Phosphate buffered Water Mesophilic aerophilic count