An approach to improve the safety and quality of ready-to-eat blueberries

Bioactive edible coatings were developed and applied to blueberries as a natural treatment. E. coli O157:H7, L. innocua, S. aureus, and P. aeruginosa were subjected to four bioactive compounds and to three film-forming solutions (FFS). Vanillin and geraniol at low concentrations (1.2-1.8 mg/mL and 0.4-1 mu L/mL) demonstrated significant inhibitory effects on all pathogens counts. Chitosan (Ch) showed a high antimicrobial activity (final counts below 2 log CFU/mL). The effectiveness of Ch plus vanillin (Ch-Va) and geraniol (Ch-Ge) in improving the safety were tested against pathogens inoculated on blueberries. Ch, Ch-Va, and Ch-Ge coatings exerted a bactericidal effect on all pathogens (from 1.24 to more than 2 log reductions). Significant reduction in yeast and mold counts was achieved with Ch (1.09 log) and Ch + Va (1.74 log). Sensory attributes of blueberries remained acceptable. Ch-Va and Ch-Ge were an alternative to improve the quality and safety and could be effective in extending the shelf life of ready-to-eat blueberries.