Food Protection with Chemicals, and by Biocontrol 323 pools Another flavor compound that imparts the aroma of butter is 2,3-pentanedione, and it has been found to be inhibitory to a limited number of Gram-positive bacteria and fungi at 500 ppm or less.95,97 The agent l-carvone imparts spearmintlike aromas and the agent d-carvone imparts carawaylike aromas, and both are antimicrobial, with the l-isomer being more effective than the d-isomer; both are more effective against fungi than bacteria at 1,000 ppm or less.97 Phenylacetaldehyde imparts a hyacinthlike aroma and has been shown to be inhibitory to S aureus at 100 ppm; and Candida albicans at 500 ppm.97,132 Menthol, which imparts a peppermintlike aroma, was found to inhibit S aureus at 32 ppm, and E coli and C albicans at 500 ppm.97,132 Vanillin and ethyl vanillin are inhibitory, especially to fungi at levels