Emerging sanitizing techniques on inoculated fresh-cut Bimi® broccoli

In the recent years food safety has become a target for the fresh-cut industry. Several outbreaks of foodborne illness caused by pathogens as Escherichia coli and Salmonella spp., among other enteric pathogens, have been widely reported in fruits and vegetables. Chlorine is the most widely used sanitizing agent for reducing pathogens on whole and fresh-cut produce, although it has some disadvantages that have led to research on new alternatives. The present work studied the single and combined effects of neutral electrolyzed water (NEW) in the washing step (ORP = 900 mV, 5°C, pH = 7, contact time = 2 min), UV-C irradiation (6 kJ m^-2) before packaging and high oxygen active modified atmosphere packaging (HO) (>50 kPa O₂ + 10-15 kPa CO₂) on Bimi^® broccoli (Brassica oleracea Italica Group × Alboglabra Group) inoculated with 6.1 and 5.2 cfu g^-1 of E. coli and Salmonella respectively. These treatments were compare with conventional NaOCl washing (100 mg L^-1, 5°C, pH = 6.5, contact time = 2 min). Inoculated samples were packed, after treatment, into polypropylene baskets under MAP conditions and were stored in darkness throughout 14 days at 5 and 10°C. Among single treatments, NEW was more effective than UV-C irradiation and HO, with a reduction of 49 and 45% for E. coli and S. enteritidis respectively. However the triple combination (NEW+UV-C+HO) was even more effective with a reduction of 56 and 49% for E. coli and S. enteritidis respectively. Generally, when stored at 5°C both pathogens counts decreased greater than at 10°C, where S. enteritidis growth was detected. As main conclusion, washing with selected NEW and a subsequent 6 kJ m^-2 UV-C treatment before packaging under high O₂ conditions seems to be a promising sanitising treatment to reduce E. coli and S. enteritidis counts in fresh-cut Bimi^® broccoli.