Antimicrobial Efficacy of Sodium Dichloroisocyanurate Washing and Coating for Reduction of Foodborne Pathogens on Fresh Blackberries

Microbial contamination of fresh berries poses a significant public health risk due to their delicate and porous structure. This study evaluated the antimicrobial efficacy of washing and coating with sodium dichloroisocyanurate (SDC) against Escherichia coli, Listeria monocytogenes, and Salmonella enterica on blackberries. Two treatment approaches were tested: washing in SDC solutions (500 ppm and 1000 ppm for 1, 4, and 8 min), and hemicellulose B-based coatings supplemented with SDC (1 and 4 min exposure). Our results demonstrated that microbial reduction was significantly influenced by SDC concentration and exposure duration; longer treatment times and higher SDC concentrations achieved greater reductions. Washing with 1000 ppm SDC for 8 min obtained reductions of 5.0 ± 0.22 Log CFU/mL for E. coli (p < 0.001), 3.6 ± 0.45 Log CFU/mL for L. monocytogenes (p < 0.01), and 4.5 ± 0.30 Log CFU/mL for S. enterica (p < 0.001). Coating treatments at 1000 ppm for 4 min achieved even greater reductions for S. enterica, reaching 6.8 ± 0.35 Log CFU/mL, which was statistically superior to the corresponding washing treatment (p < 0.001). These findings support SDC as a promising antimicrobial agent for blackberry decontamination using a washing or coating method, with potential applications in fresh produce safety.