Measuring the antimicrobial activity of natural extracts against food spoilage bacteria to enhance food hygiene: preliminary in vitro results

Abstract

Food products are prone to microbial contamination able to affect their safety and quality attributes and their nutritional value. The interest in the potential use of bioactive compounds deriving from natural matrices, especially agro-industrial wastes, as alternatives to classical food preservatives has rapidly increased. In the present study a food grade olive mill wastewater polyphenolic extract and a commercial mix were characterised and their antioxidant and antimicrobial capacity were assessed. The antimicrobial activity was preliminary assessed in vitro by agar well diffusion, subsequently by microdilution method to define the minimum inhibitory and bactericidal concentration. The olive mill wastewater polyphenolic extract registered a higher antioxidant capacity [(13.3 ± 1.0) 102 µgTE/(100 g)] and antimicrobial efficacy (max MBC value 0.2500 g/mL) compared to commercial mix with wide potential application in food industry.