Combined effect of antimicrobial coatings, gamma radiation and negative air ionization with ozone on Listeria innocua, Escherichia coli and mesophilic bacteria on ready-to-eat cauliflower florets

• The antimicrobial coating induced inhibition of the bacterial growth during storage.
• Negative air ionization + ozone treatments can be used to reduce bacterial growth.
• Coating combined with gamma radiation inhibited the growth of Listeria and E. coli.
• An additive effect was observed between the antimicrobial coating and NAI/ozone.
• A synergic effect was observed between the antimicrobial coating and gamma radiation.

The objective of this study was to evaluate the effect of a bioactive edible coating combined with a low γ-radiation dose or negative air ionization (NAI) with ozone on the microbiological quality of ready-to-eat cauliflowers. Results showed that each treatment alone was effective on Listeria innocua, Escherichia coli and mesophilic bacteria. After 7 d, treatment with γ-radiation reduced L. innocua and E. coli of 1.8 and 3.6 log CFU g−1 respectively while NAI + ozone reduced L. innocua and E. coli of 2.0 and 2.8 log CFU g−1 respectively. Mesophilic bacteria were reduced of 1.8 log CFU g−1 after γ-radiation and 1.4 log CFU g−1 after NAI + ozone. This study demonstrated that the bioactive coating acts in synergy with γ-radiation, inducing no bacterial growth of L. innocua and E. coli, as well as a control of the growth of mesophilic bacteria during 7 d. The combination of bioactive coating and NAI + ozone induced an additive effect on L. innocua, E. coli and mesophilic bacteria, and suggests potential antioxidant properties of the coating.