Author details

pH values comparing its growth in liquid and solid media; they found that while there was no significant effect of the physical state of the media on the growth of colonies in the absence of the EO, the type of media did have an influence on the inhibitory efficacy of oregano EO. Identical treatments with 0.03% oregano EO showed increased effectiveness in liquid culture than in gelatin gel, attributed to a better dispersion of tested EO in broth which could increase the interaction between

Contour plots for Salmonella cocktail (log CFU/mL) as a function of (a) thyme essential oil and pH, (b) thyme

For the Listeria cocktail, only a 2.54 log reduction could be expected at pH 6.0 with the lowest ISP (10% w/w) and highest thyme EO (0.25% w/w) tested concentrations, while for the Salmonella cocktail, the highest reduction (2.19 log) was achieved at an ISP concentration of 11.5% w/w with a pH 5.5 and 0.25% w/w of thyme EO.

Even though thymol was not found as a component of tested thyme essential oil, its antimicrobial activity did not seem to be affected, exhibiting minimum inhibitory and bactericidal concentrations similar or better than those found in other published reports. As expected, more thyme essential oil is needed to inhibit bacteria in food model media with high protein content than for laboratory media. Experiments with higher concentrations of tested thyme essential oil should be carried out seeking more pronounced log reductions in both studied bacterial cocktails. Additionally, complementary experiments are needed to validate the models

cells and EO antimicrobial components.

essential oil and isolated soy protein, or (c) pH and isolated soy protein.

Technology, Science and Culture - A Global Vision, Volume II

4. Conclusions

Figure 2.

obtained in this study.

100

Leonor Lastra Vargas\*, Aurelio Lopez-Malo\* and Enrique Palou\* Department of Chemical and Food Engineering, Universidad de las Américas Puebla, Cholula, Puebla, Mexico

\*Address all correspondence to: leonor.lastravs@udlap.mx, aurelio.lopezm@udlap.mx and enrique.palou@udlap.mx

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
