Effect of sodium benzoate on the growth and enzyme activity of Aspergillus niger and Penicillium citrinum in Zobo drink during storage at 30 ± 2°C

The effect of different concentrations of sodium benzoate on the growth and enzyme elaboration potentials of Aspergillus niger and Penicillium citrinum in zobo drink packaged in glass bottles were investigated. All the tested concentrations of 0.025, 0.05 and 0.075% (w/v) caused decreases in the counts of A. niger and P. citrinum at 30 ± 2°C. Concentration of 0.05% (w/v) of the preservative hurdle showed complete inhibition of A. niger in the 4th week whereas the same effect was observed in the 5th week on P. citrinum. Enzyme activity in the control experiments was significantly higher (P < 0.05) than those of treated and fresh Zobo samples.