Efficacy Studies of Bromine-based Biocides for the Control of Microorganisms on Pork

Introduction: Pork meat offers a favorable environment for growth of spoilage organisms and pathogens, therefore antimicrobials or other adequate technologies need to be applied to pork products to ensure safety.  Although bromine-based antimicrobials have been widely used in recreational and industrial water treatment for many years, they have only recently been approved for use in some food safety applications.  Some advantages of bromine-base biocides are:  their effectiveness at a wider range of pH values than chlorine, low odor and minimal effect on organoleptic properties.

Purpose: Evaluate DBDMH (1,3-Dibromo-5,5-Dimethylhydantoin), a bromine-based biocide, as means to control bacteria in the pork industry.

Methods: Salmonella enterica was grown overnight at 37°C in Luria-Bertani broth. Pork bellies purchased from a local slaughterhouse were cut into 100 cm² pieces, UV-treated for 30 minutes, spot inoculated on muscle or skin side with 6 log CFU/cm² of Salmonella and allowed attachment for 30 minutes at room temperature. Samples were hung, sprayed from both sides for 15 seconds at 60 PSI for each treatment and allowed to drip for one minute.  Treatments included DBDMH 300 ppm (as bromine), peroxyacetic acid (PAA) at 200 ppm or 2% lactic acid. Samples in 0.1% buffered peptone water were rocked, serially diluted and analyzed using standardized methods to detect and quantify Salmonella and Enterobacteriaceae (EB).  Positive and negative controls were handled identically.

Results: DBDMH, PAA and lactic acid reduced Salmonella inoculated on skin side by 1.47, 1.47 and 1.38 log CFU/cm², and on muscle side by 0.82, 0.82 and 1.09 log CFU/cm², respectively.  They reduced EB’s on skin side by 1.5, 1.48 and 1.45 log CFU/cm², and on muscle side by 0.67, 0.74 and 1.25 log CFU/cm², respectively.

Significance:   DBDMH is an effective intervention to reduce bacteria in the pork industry.  Although this study used 300 ppm (as bromine), the FDA’s food contact substance notification 1190 allows concentrations up to 900 ppm.