Testing the Antimicrobial Effects of Some Hydrosols on Food Borne-Pathogens and Spoilage Bacteria

Abstract

The antimicrobial activity of five hydrosols made from orange peel, pomegranate peel, shaddock peel, mandarin peel, and thyme plant was tested by microdilution and disc diffusion methods against 3 foodborne bacteria (Staphylococcus aureus, Salmonella Parathyphi A and Klebsiella pneumoniae) and 3 fish spoilage bacteria (Vibrio vulnificus, Pseudomonas luteola, and Photobacterium damselae). S. Parathyphi A was one of the most susceptible bacteria against all hydrosols tested mainly pomegranate, thyme and shaddock peel (with more than 10.5 mm inhibition zone). Inhibition zones on the growth of S. aureus were only observed from hydrosols of thyme and mandarin peel. Hydrosols made from orange and mandarin peel were effective on inhibition of the growth of fish spoilage bacteria. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of hydrosols were generally 50 and >50 mg/mL, respectively. These results show that thyme and pomegranate peel hydrosols had the strongest antimicrobial effects against test bacteria, although the effect of waste hydrosols vary depending on bacterial strains.