ANTIMICROBIAL EFFECT OF CINNAMON BARK EXTRACT ON ESCHERICHIA COLI O157:H7, LISTERIA INNOCUA AND FRESH-CUT APPLE SLICES

The potential for natural antimicrobial compounds extracted from true cinnamon (Cinnamomum zeylanicum Nees ) to use as a food additive to extend the shelf life of fresh-cut apples was investigated. Several different extracts were prepared using cinnamon bark and powder to evaluate their antimicrobial activity on two marker microorganisms, Escherichia coli O157:H7 and Listeria innocua. An ethanolic extract of cinnamon bark (2% w/v) inhibited the growth of E. coli and L. innocua by 94 and 87%, respectively. When incorporated in a commercial antibrowning dipping solution, FreshExtend, the cinnamon bark extract (1% w/v) reduced significantly (P < 0.05) the microbial growth on apple slices stored for 12 days at 6C in comparison to the control. The cinnamon extract had no influence on the antibrowning properties of FreshExtend. Liquid chromatography mass spectrometry analysis showed that the major chemical constituent of this extract is cinnamic aldehyde. PRACTICAL APPLICATIONS The consumer demand for convenient and nutritious, minimally processed produce like fresh-cut apples has been steadily increasing. Identification of natural antimicrobial agents that are acceptable to the consumer is a challenge to the fresh-cut industry. In this study, we discovered antimicrobial properties of a cinnamon extract and identified the principal antimicrobial compound as cinnamic aldehyde. For the first time, we demonstrated that this generally recognized as safe (GRAS) compound could be used with a commercial post-cut dipping solution (FreshExtend) to inhibit significantly the microbial growth on refrigerated apple slices. Therefore, this innovative study provides a new insight into the possible use of cinnamon extracts or cinnamic aldehyde as natural antimicrobial agents in the processing of sliced apples and other minimally processed fruits and vegetables to assure the microbial food safety.