Location: Healthy Processed Foods ResearchTitle: Apple, carrot, and hibiscus edible films containing the plant antimicrobials carvacrol and cinnamaldehyde inactivate Salmonella Newport on organic leafy greens in sealed plastic bags) Author
Submitted to: Journal of Food Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/21/2013
Publication Date: 11/27/2013
Publication URL: dx.doi.org/10.1111/1750-3841.12318
Citation: Zhu, L., Olsen, C.W., McHugh, T.H., Friedman, M., Jaroni, D., Ravshankar, S. 2013. Apple, carrot, and hibiscus edible films containing the plant antimicrobials carvacrol and cinnamaldehyde inactivate Salmonella Newport on organic leafy greens in sealed plastic bags. Journal of Food Science. 79(1):M61-M66. DOI: 10.1111/1750-3841.12318. Interpretive Summary: The increased demand for organic leafy greens may increase the risk of foodborne illness outbreaks owing to the consumption of contaminated produce. Edible films incorporated with natural antimicrobials can to be used as additives into organic bagged salads to control pathogenic contamination. The results of the present study showed that edible films incorporated with natural antimicrobials effectively reduce S. Newport in contaminated salads. Films containing carvacrol exhibited better antimicrobial activity against S. Newport than did cinnamaldehyde-containing films. The tested films showed the highest antimicrobial effects on iceberg lettuce. These results suggest that the antimicrobial vapor emanating from the films could be retained in the sealed salad bags and maintain the antimicrobial activity. These results could provide the leafy green industry with an option for choosing novel functional food packaging. The sensory evaluation of salad samples exposed to the three edible films needs further investigation. This research was supported by the U.S. Department of Agriculture- National Institute of Food and Agriculture-Organic Research and Extension Initiative Competitive Grant no. 2010-51300-21760.
Technical Abstract: The objective of this study was to investigate the antimicrobial effects of carvacrol and cinnamaldehyde incorporated into apple, carrot and hibiscus based edible films against Salmonella Newport in contaminated organic leafy greens. The leafy greens tested included romaine and iceberg lettuce, and mature and baby spinach. Each leafy green sample was washed, dip inoculated with S. Newport (107 CFU/mL) and dried. Each sample was put into a Ziploc bag. Edible films pieces were put into the Ziploc bag and mixed well. The bags were sealed and stored at 4°C. Samples were taken at Days 0, 3, and 7 for enumeration of survivors. On all leafy greens, 3% carvacrol films showed the best bactericidal effects against Salmonella. All three types of 3% carvacrol films reduced the Salmonella population by 5 log CFU/g at day 0 and 1.5% carvacrol reduced the Salmonella by 1–4 log CFU/g at day 7. The films with 3% cinnamaldehyde showed 0.5–3 log reductions on different produce. The films with 0.5 and 1.5% cinnamaldehyde and 0.5% carvacrol slightly reduced the Salmonella population. In general, carvacrol films were more effective than cinnamaldehyde films. Edible films were most against Salmonella on iceberg lettuce. This study demonstrates the potential of edible films incorporated with carvacrol and cinnamaldehyde to inactivate S. Newport on organic leafy greens in plastic bags.