Brown, green and red propolis extracts: characterisation and potential as preservatives of ripened cheeses

Propolis is a natural product with potential use as preservative. Polyphenols' composition and biological activities of ethanolic and aqueous extracts of poplar-brown propolis (BP), green propolis (GP) and red propolis (RP) were researched. Antimicrobial activity against different common spoilage and toxigenic cheese moulds (Penicillium commune and P. verrucosum), P. camemberti, P. roqueforti and three pathogens (Listeria monocytogenes, Staphylococcus aureus and Escherichia coli) were evaluated. BP and RP ethanol extracts at concentration of 5 mg/mL and aqueous BP extract at 100-150 mg/mL could be used as promising natural preservatives. The total phenolics' and flavonoids' contents, as well as characteristic phenolic compounds of each type of propolis were likely the main responsible for antioxidant and antimicrobial activities. Although ethanolic extracts showed the best results, aqueous extracts could be also interesting for the cheese industry because they demonstrated to be able to prevent spoilage and potential toxicity of cheeses.