Biological control of postharvest spoilage and diseases in apples caused by pathogens, using plant extracts in collaboration with a chitosan-based coating

Abstract

The aim of this study is to evaluate the antimicrobial activity of 7 plant extracts with minimum inhibitory (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) against Escherichia coli, Staphylococcus aureus and Penicillium expansum and the application of the chitosan edible coating incorporated with extract in apple. The results showed thyme and chamomile extracts presented the lowest MIC (0.39 and 0.78 mu g/mL, respectively) and MBC (0.78 and 1.56 mu g/mL, respectively) values against all tested microorganisms. To investigate the microstructural changes of chitosan-based (Ch) coatings caused by the addition of free extract (Ex), analyses of total soluble solids, pH, lesion diameter, and organoleptic properties were conducted. The results showed a decay inhibition of 40 and 80 after 7 days for Ch and Ch + Ex, respectively. In addition, thyme extract coatings showed the maximum inhibitory effect and the best effect on fruit quality and decay, and are suitable antimicrobial agents for active packaging in fruits.