EFFECT OF STATIC MAGNETIC FIELD ON MICROBIAL GROWTH KINETICS AND PHYSIOCHEMICAL PROPERTIES OF NONO (FERMENTED MILK DRINK)

Abstract

This study assessed the effect of 0.5T static magnetic field (SMF) on microbial growth kinetics and physiochemical properties of Nono drinks stored at uncertain condition for six days. Magnetatic bacterial were predominated by Lactobacillus casei (40%), Corynebacterium sp(50%), and Staphylococcus sp (10%); while fungi were Penicillum sp(30%), Mucorsp(20%) and Aspergillus sp(50%). SMF significantly (P<0.05) altered the average pH (2.26-2.31) and total titratable acidity (0.13-0.17%v/v) compared to the average controls of 2.08 and 0.20%v/v respectively. However, SMF had no significant impact on the temperature and sensory properties (≤ 3 score of 7-point hedonic scale ranking) of Nono drinks when compared to the control samples after six days assessment. Microbial growth kinetic was relatively stable within 72hrs, thereafter, SMF treated samples steadily declined by 30.5%while non-SMF (control) samples increased by 26.25%. Microbial growth kinetics was observed to have direct and inverse correlations to total titratable acidity and pH respectively. Conclusively, SMFhave correlative inhibitory impact on microbial growth rate with consequential acidityincrease that would slow down the rate of spoilage. Thus, inclusion of SMF to hurdle technology would prolong diary products' shelf-life with minimal sensory alterations.