Full Length Research Paper

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

O. E. Nwafor¹* and M. J. Ikenebomeh²

¹Department of Microbiology, Delta State University, Abraka, Nigeria.

²University of Benin, Benin City, Nigeria.

*Corresponding author. E-mail: obiomanwafor@yahoo.com. Tel.: 08035878792.

Accepted 13 March, 2009

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 4^th week whereas the same effect was observed in the 5^th week on P. citrinum. Enzyme activity in the control experiments was significantly higher (P < 0.05) than those of treated and fresh Zobo samples.

Key words: Sodium benzoate, enzyme activity, Zobo drink.