Effect of Vanillin, Ethyl Vanillin, and Vanillic Acid on the Growth and Heat Resistance of Cronobacter Species

Abstract

Preservatives could be part of an effective intervention strategy for the control of Cronobacter species in foods, but few compounds with the desired antimicrobial properties have been identified to date. We examined the antibacterial activity of vanillin, ethyl vanillin, and vanillic acid against seven Cronobacter spp. in quarter-strength tryptic soy broth with 5 g/liter yeast extract (TSBYE) adjusted to pH 5.0, 6.0, and 7.0 at 10, 21, and 37°C. All compounds exhibited pH- and temperature-dependant bacteriostatic and bactericidal activity. MICs of vanillin and ethyl vanillin consistently increased with decreasing pH and temperature, but vanillic acid had little activity at pH values of 6.0 and 7.0. The MICs for all temperatures, pH values, and bacterial strains tested were 2 mg/ml ethyl vanillin, 3 mg/ml vanillin, and >8 mg/ml vanillic acid. MBCs also were influenced by pH, although significantly higher concentrations were needed to inactivate the bacteria at 21°C than at 10 or 37°C. Survivor curves for Cronobacter sakazakii strains at the MBCs of each compound revealed that all treatments resulted in immediate loss of cell viability at 37°C. Measurements of propidium iodide uptake indicated that the cell membranes were damaged by exposure to all three compounds. The thermal resistance of C. sakazakii was examined at 58°C in TSBYE supplemented with MBCs of each compound at pH 5.0 and 6.0. D-values at pH 5.0 were reduced from 14.56 ± 0.60 min to 0.93 ± 0.01, 0.63 ± 0.01, and 0.98 ± 0.02 min for vanillin, ethyl vanillin, and vanillic acid, respectively. These results suggest that vanillin, ethyl vanillin, and vanillic acid may be useful for the control of Cronobacter spp. in food during preparation and storage.

Evaluation of process involved in the production of aromatic compounds in Gram‐negative bacteria isolated from vanilla ( Vanilla planifolia ex. Andrews) beans

“…While, the VR of Enterobacter IFVB were higher than the values reported by Li et al () (18 µg ml −1 ) and Citrobacter IFVB showed lower values of VR in comparation with other results (3000 μg ml −1 ) (Harazono et al ). Compared with Yemiş et al (), our results confirmed the resistance to VA on Enterobacter species (8 μg ml −1 ). Also, Harazono et al (), indicated that some Gram‐negative bacteria like Citrobacter are VAR, because they contained AC biosynthetic enzymes (Harazono et al ; Ito et al ).…”

Antibacterial activity of polyphenol-rich pomegranate peel extract against Cronobacter sakazakii

“…Simple phenolic compounds including vanillic acid, ethyl vanillin and vanillin can lessen the heat resistance of C. sakazakii and inhibit growth in reconstituted powdered infant formula. [22] Comparatively little data is available on the antibacterial activity of higher molecular weight polyphenols against the species. Pina-Pérez et al [23] reported that a polyphenol-rich cocoa powder inhibited growth of C. sakazakii in reconstituted infant milk formula stored at 25°C.…”

Bacteria: Cronobacter (Enterobacter) sakazakii and Other Cronobacter spp.

“…Kim et al (2010b) have also shown that red muscadine juice can cause a 6-log reduction of C. sakazakii in commercial baby juices in approximately 2 h. Their results suggest that red muscadine could be used to prevent and/or control C. sakazakii in baby food formula. Recently, Yemis et al (2011) investigated the antibacterial activity of vanillin, ethyl vanillin, and vanillic acid as possible preservatives in the intervention strategy for control of Cronobacter spp. They evaluated the effectiveness of the compounds on the growth and heat resistance.…”