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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Healthy Processed Foods Research » Research » Publications at this Location » Publication #368969
Research Project: New Sustainable Processing Technologies to Produce Healthy, Value-Added Foods from Specialty Crops

Location: Healthy Processed Foods Research

Title: Edible films containing carvacrol and cinnamaldehyde inactive Escherichia coli O157:H7 on organic leafy greens in sealed plastic bags

Author
item ZHU, LIBIN - University Of Arizona
item Olsen, Carl
item McHugh, Tara
item Friedman, Mendel
item Levin, Carol
item JARONI, DIVYA - Oklahoma State University
item RAVISHANKAR, SADHANA - University Of Arizona

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2020
Publication Date: 1/6/2020
Citation: Zhu, L., Olsen, C.W., McHugh, T.H., Friedman, M., Levin, C.E., Jaroni, D., Ravishankar, S. 2020. Edible films containing carvacrol and cinnamaldehyde inactive Escherichia coli O157:H7 on organic leafy greens in sealed plastic bags. Journal of Food Safety. 40(2). Article e12660. https://doi.org/10.1111/jfs.12758.
DOI: https://doi.org/10.1111/jfs.12758

Interpretive Summary: In a collaborative study with the University of Arizona in Tucson, we investigated the antimicrobial effects of carvacrol, the main ingredient of oregano oil, and cinnamaldehyde, the main ingredient of cinnamon oil, incorporated into apple-, carrot-, and hibiscus-based edible films prepared in this laboratory against the foodborne pathogen E. coli O157:H7 in bagged iceberg lettuce, romaine lettuce, and baby and mature spinach. The results showed that edible films containing carvacrol or cinnamaldehyde effectively reduced E. coli O157:H7 in contaminated bagged leafy greens. Films containing carvacrol exhibited better antimicrobial activity against E. coli O157:H7 than cinnamaldehyde-containing films. The edible films showed the best antimicrobial effects on Iceberg lettuce. The results also suggest that the antimicrobial vapors released from the films could be retained in the sealed salad bags and maintain the antimicrobial activity. Edible films incorporated with natural plant antimicrobials can be used as additives into organic bagged salads to control E. coli O157:H7 contamination. The use of edible films containing natural antimicrobials can meet the increased consumer demand for natural and safe salads. These results could provide the organic leafy green industry with an option for choosing novel functional food packaging. The sensory properties of the organic leafy greens exposed to the edible films containing antimicrobials need further investigation.

Technical Abstract: The antimicrobial effects of apple-, carrot-, and hibiscus-based edible films containing carvacrol and cinnamaldehyde against Escherichia coli O157:H7 on organic leafy greens in sealed plastic bags were investigated. Fresh-cut romaine and iceberg lettuce, mature and baby spinach leaves were inoculated with E. coli O157:H7 and placed into Ziploc® bags. Edible films were then added into the bags, which were stored at 4 °C. The evaluation of samples taken at days 0, 3 and 7 showed that on all leafy greens, 3% carvacrol-containing films had the greatest effect against E. coli O157:H7, reducing the bacterial population by about 5 log CFU/g on day 0. All three types of 3% carvacrol-containing films reduced E. coli O157:H7 by about 5 log CFU/g at day 0. The 1.5% carvacrol-containing films reduced E. coli O157:H7 by 1-4 logs CFU/g at day 7. Films with 3% cinnamaldehyde showed 0.6-3 logs CFU/g reductions on different leafy greens.