ANTIMICROBIAL ACTIVITY OF SHREDDED CARROT EXTRACTS ON FOOD-BORNE BACTERIA AND YEAST

Purified ethanolic extracts of peeled and shredded carrots showed an a ntimicrobial effect against a range of food-borne micro-organisms. The minimum inhibitory concentration, expressed as mg ml(-1) dried carrot material used for the extraction were: Leuconostoc mesenteroides, 27; Listeria monocytogenes, >27 <55; Staphylococcus aureus, >27 <55; Pseu domonas fluorescens, >55 <110; Candida lambica, >55 <110; Escherichia coli, >110 <220. The antimicrobial activity was not linked to phenolic compounds but was presumably due to apolar components. Free saturated fatty acid (dodecanoic acid) and methyl esters of saturated fatty aci ds (of dodecanoic and pentadecanoic acids) were identified in purified active extracts of carrots by gas chromatography coupled to mass spec trometry and could be responsible for the antimicrobial activity. This effect did not seem to play a role in the resistance of shredded carr ots to microbial spoilage, although the antimicrobial activity was pre sent in fresh carrots at concentrations sufficient to inhibit spoilage bacteria.