Combination of ultrasound and antimicrobial compounds towards Pichia spp. and Wickerhamomyces anomalus in pineapple juice

•Power affected yeasts viability more than the duration of pulse or of the time.•US reduced the initial cell count; antimicrobials controlled the growth.•The effect of antimicrobials was not univocal.

This research addresses the use of ultrasound (US) as a tool to inhibit Wickerhamomyces anomalus, Pichia guilliermondii and Pichia membranifaciens: they were initially inoculated in distilled water and US-treated by modulating power (40-80%), duration of the treatment (2-6 min) and pulse (2-6 s). Thereafter, yeasts were inoculated in a lab medium, containing a commercial citrus extract and/or sodium benzoate, and US-treated; finally, a challenge test in pineapple juice was performed, using W. anomalus as a model yeast. The results showed that power was the most significant parameter for the anti-yeast effect of US; however, the treatment could not prevent the growth of survivors within storage, thus the use of antimicrobials is advisable as an additional tool to prevent yeast spoilage.