Development of Flexible Antimicrobial Films Using Essential Oils as Active Agents

Abstract

The antimicrobial activity in the vapor-phase of laboratory-made flexible films of polypropylene (PP) and polyethylene/ethylene vinyl alcohol copolymer (PE/EVOH) incorporating essential oil of cinnamon ( Cinnamomum zeylanicum), oregano ( Origanum vulgare), clove ( Syzygium aromaticum), or cinnamon fortified with cinnamaldehyde was evaluated against a wide range of microorganisms: the Gram-negative bacteria Escherichia coli, Yersinia enterocolitica, Pseudomonas aeruginosa, and Salmonella choleraesuis; the Gram-positive bacteria Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, and Enterococcus faecalis; the molds Penicillium islandicum, Penicillium roqueforti, Penicillium nalgiovense, Eurotium repens, and A spergillus flavus and the yeasts Candida albicans, Debaryomyces hansenii, and Zigosaccharomyces rouxii. Films with a nominal concentration of 4% (w/w) of fortified cinnamon or oregano essential oil completely inhibited the growth of the fungi; higher concentrations were required to inhibit the Gram-positive bacteria (8 and 10%, respectively), and higher concentrations still were necessary to inhibit the Gram-negative bacteria. PP films were more effective than PE/EVOH films. The atmospheres generated by the antimicrobial films inside Petri dishes were quantitatively analyzed using headspace-single drop microextraction (HS-SDME) in combination with gas chromatography-mass spectrometry (GC-MS). The analyses showed that the oregano-fortified PP films released higher levels of carvacrol and thymol, and the cinnamon-fortified PP films released higher levels of cinnamaldehyde, during the first 3-6 h of incubation, than the corresponding PE/EVOH films. Shelf-life tests were also performed, demonstrating that the antifungal activities of the films persisted for more than two months after their manufacture. In addition, migration tests (overall and specific) were performed, using both aqueous and fatty simulants, to ensure that the films meet EU regulations regarding food contact materials. Following contact with the tested films, the substances that had migrated into the aqueous simulants were recovered by direct immersion-single drop extraction (DI-SDME) and then analyzed by GC-MS. The fatty stimulant (isooctane) was directly injected into the chromatographic system.

Traceability of Active Compounds of Essential Oils in Antimicrobial Food Packaging Using a Chemometric Method by ATR-FTIR

“…Antimicrobial packaging, an innovative concept, can be defined as a kind of active packaging in which the package, the product, and the environment interact to reduce, inhibit, or retard the growth rate of microorganisms [11]. In these technologies, researchers are developing food packaging materials such as synthetic films [10] [11] [12] and edible films [16]- [22] with antimicrobial properties. Polymers are effective vehicles for the active substances [23], giving the possibility to incorporate different antimicrobial additives [1] [24] [25] [26].…”

Carvacrol and Thymol for Fresh Food Packaging

“…These plant EOs are volatile liquids characterized by a strong odor [13]. Extracts derived from herbs and EOs contain many natural compounds such as thymol, linalool and carvacrol with a broad AM range against different pathogenic and spoilage microorganisms including Gram-negative [14,15] and Grampositive species [16,17]; as well as against yeast [18] and molds [19]. In general, these additives are considered to be safe and they have been classified as GRAS (Generally Recognized As Safe) by the American Food and Drug Administration [20].…”

Development of Antimicrobial Plant Extracts and its Application to Cosmetics

“…It is known that some plant extracts and essential oil from herbs have antimicrobial activity [5][6][7]. For example, the essential oils of Rosmarinus officinalis and Cinnamomum zeylanicum have been used for their antimicrobial properties [8][9][10].…”