Effect of shear rate and oxygen stresses on the survival of Lactococcus lactis during the atomization and drying stages of spray drying: A laboratory and pilot scale study

► Integral effect of shear and oxygen on survival of lactic acid bacteria during spray drying was investigated. ► Much higher percentage of bacterial death was found to occur in atomization rather than in drying stage. ► Shear-induced bacterial death at atomization stage was much higher in pilot than in laboratory spray dryers. ► Use of oxygen scavenger in the feed substantially lowered the bacterial death during atomization and drying. ► The use of N2 gas during atomization substantially reduced the bacterial death during atomization and drying.