Rosmarinus officinalis reduces the ochratoxin A production by Aspergillus westerdijkiae in a dry-cured fermented sausage-based medium

Aspergillus westerdijkiae is an ochratoxin A (OTA) producer mould in dry-cured meat products. To prevent the presence of ochratoxigenic moulds in dry-cured fermented sausages, natural strategies based on the use of herbs and their derivatives are in the spotlight. The aim of this study was to test the potential antiochratoxigenic effects of rosemary leaves (R) and rosemary essential oil (REO) as biocontrol agents (BCAs) in a dry-cured fermented sausage-based medium. The mechanisms involved in their effects were also analysed by Proteomics. A control without BCAs and three treatments (R, REO and the combination of R + REO) were carried out. No significant differences were detected when BCAs were individually applied, whilst a significant reduction up to 73.87% in OTA was provoked by R + REO. This combination showed a synergistic effect, in which proteins from PKS ER domain and cell wall integrity pathway seem to be involved. REO alone exerted similar effect on the mould proteome than R + REO, but in a lesser extent. The impact of R in this synergy has not been completely elucidated. The combination of R + REO together with other strategies could minimise the hazard posed by A. westerdijkiae in dry-cured fermented sausages. •Rosemary plus its essential oil reduced ochratoxin A in Aspergillus westerdijkiae.•The combination of rosemary plus its essential oil presented a synergistic effect.•The combination altered proteins from mycotoxin biosynthesis and cell wall integrity.•The essential oil had similar effects on the proteome than the combination treatment.