Growth, development and thermal resistance of Bacillus atrophaeus spores using whey culture media

Abstract

Whey represents an important environmental problem for the dairy industry due to its high volume and organic load. Studies that evaluate new forms of use of these residues such as growth medium for microorganisms, can help to develop a better destination providing an added value bioproduct. This work aims to evaluate the development of Bacillus atrophaeus spores ATCC 9372 growing in whey culture media to determine the reuse of this dairy residue. Whey at a concentration varying from 1.0g. L-1 to 20.0g. L-1 was dissolved into water and Bacillus atrophaeus spores were incubated for 6 days. Thermal treatments were performed at 102oC and 104oC and in all conditions evaluated, the decay of spores population was linear. In solid media, D-values at 102oC ranged from 1.24 min to 2.98 min and at 104oC ranged from 1.27 min to 2.35 min. The culture media containing whey can enable the growth and sporulation of Bacillus atrophaeus. This study confirms the possibility of using this dairy industry residue as an alternative to obtain bacterial spores, which may be used in validation of thermal.