Gillian O Bruni and Evan Terrell
USDA-ARS Southern Regional Research Center, 1100 Allen Toussaint Blvd, New Orleans, LA 70124, United States of America; gillian.bruni@usda.gov
Microbial isolates from sugar crop-processing facilities were tested for susceptibility to industrial antimicrobial agents to determine minimum inhibitory concentration (MIC) values for optimal dosing. Hydritreat 2216 (peracetic acid) showed broad spectrum activity against all bacterial isolates as well as Saccharomyces cerevisiae. Sodium hypochlorite (bleach) showed broad spectrum activity against all isolates, but at much higher effective concentrations. Hops BetaStab XL (Hops acid) specifically inhibited Gram-positive isolates. Magna Cide D (carbamate) MIC value was lowest for S. cerevisiae and Zymomonas mobilis but was less effective against Gram-positive bacterial strains. Based on laboratory experiments, factory losses of sucrose from a single microbial species in the absence of antimicrobials could range from 0.13 to 0.52 kg sucrose per tonne of cane. Additional improvements in sugar yield are anticipated from agents with broad spectrum activity. A cost analysis was conducted considering sucrose savings due to antimicrobial application to provide estimates for break-even costs, which ranged from approximately USD0.50 to USD2.00 per L for a given antimicrobial agent.