Comparative Inhibitory Effects Of Sodium And Potassium Chloride Salts On Staphylococcus Aureus From Fermented Pentaclethra Macrophylla:- Ugwuala, Elijah B

ABSTRACT

Chemical preservatives in foods are nowadays added at lower concentrations. However, this may allow survival ofbacterial cells and induce increased resistance to various preservatives. The study was conducted to evaluate comparatively the individual effects of sodium (NaCI) and potassium (K.CI) chloride salts against Staphylococcus aureus isolated from fermented Pentaclethra macrophylla. A total oftwenty (20) traditionally fermented food samples were purchased from a market in Umuahia metropolis. Isolation and identification of Staphylococcus aureus were conducted using standard microbiological techniques. Staphylococcus aureus was identified using standard morphological and biochemical tests. The inhibitory effect of both salts were analyzed on nutrient agar and nutrient broth. The highest optical density recorded as a result of contact with varying concentration of sodium chloride was 0.48 at 5% concentration after 48hours incubation while the least was 0.04 at 20% concentration after 12hours incubation while the highest optical density recorded as a result of contact with varying concentration of potassium chloride was 0.41 at 5% concentration after 48hours incubation while the least was 0.01 at 20% concentration after 12hours incubation. Higher salt concentrations of the medium increase its osmolarity, which is likely to have resulted in hyper osmotic shock to Staphylococcus aureus cells causing growth suppression. Relative maximum specific growth rate were exhibited as a function ofthe chloride salt concentrations. Consequently, it can be concluded that increasing the salt concentration in the medium partially overcame the inhibition of growth of.S’. aureus at longer incubation period.