Mixture design methodology and predictive modeling for developing active formulations using essential oils and citrus extract against foodborne pathogens and spoilage microorganisms in rice

Authors: BEGUM, T - Institut National De La Recherche Scientifique (INRS); Follett, Peter; SHANKAR, S - Institut National De La Recherche Scientifique (INRS); MAHMUD, J - Institut National De La Recherche Scientifique (INRS); SALMIERI, S - Institut National De La Recherche Scientifique (INRS); LACROIX, M - Institut National De La Recherche Scientifique (INRS)

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2021
Publication Date: 12/17/2021
Citation: Begum, T., Follett, P.A., Shankar, S., Mahmud, J., Salmieri, S., Lacroix, M. 2021. Mixture design methodology and predictive modeling for developing active formulations using essential oils and citrus extract against foodborne pathogens and spoilage microorganisms in rice. Journal of Food Science. 87(1):353-369. https://doi.org/10.1111/1750-3841.15988.
DOI: https://doi.org/10.1111/1750-3841.15988

Interpretive Summary: Plant essential oils (EOs) have microbicidal effects against food-borne pathogens in the vapor phase. The efficacy of 18 plant essential oils and natural extracts were tested alone or in combination against two bacteria, Escherichia coli and Salmonella Typhimurium and three fungi, Aspergillus niger, Penicillium chrysgenum, and Mucor circinelloides. A combination treatment of Origanum compactum EO+organic citrus extract showed the highest activity against the five microbes in bioassays and packaged rice. Plant EOs have potential as a fumigant treatment for a wide variety of food products, either as added sachets or in bioactive packaging films, to improve food safety.

Technical Abstract: The antibacterial and antifungal effects of eighteen plant-derived essential oils (EOs) and four natural extracts (NEs) were studied against two pathogenic bacteria (Salmonella Typhimurium and Escherichia coli O157:H7) and three fungi (Aspergillus niger, Penicillium chrysogenum, Mucor circinelloides). The minimal inhibitory concentration (MIC) of EOs and NEs were assessed using broth microdilution assay. The checkerboard method was used to determine the possible interaction between the EOs and the NEs. In the MIC assay, Cinnamomum verum, Origanum compactum, Origanum heracleoticum, Citrus sinensis, organic citrus extract, and natural citrus extract showed the highest antimicrobial and antifungal properties. Many of the combinations showed synergistic effects against some of the bacteria and fungi, but only the combination of O. compactum EO and organic citrus extract showed synergistic activity having enhanced efficiency against E. coli, S. Typhimurium, A. niger, P. chrysogenum, and M. circinelloides. A mathematical modified Gompertz model was applied to evaluate the growth parameters, maximum colony diameter (A), maximum growth rate (Vm), and lag phase ('), under the seven most effective EOs and NEs (C. verum, Cymbopogon flexuosus, O. compactum, O. heracleoticum, C. sinensis, organic citrus extract, natural citrus extract) and one combination (O. compactum EO+organic citrus extract) using vapor assay. The vapor of O. compactum EO+organic citrus extract significantly (P=0.05) reduced the growth rate and maximum colony diameter of E. coli, S. Typhimurium, A. niger, P. chrysogenum, and M. circinelloides, and extended their lag phase from 1 day to 5 days. The in situ tests showed a significant reduction (P=0.05) of all tested pathogenic bacteria and fungi using the vapor of O. compactum EO+organic citrus extract at day 28 of storage rice.