Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/24/2002
Publication Date: 10/1/2002
Citation: Friedman, M., Henika, P.R., Mandrell, R.E. 2002. Antimicrobial activities of phenolic benzaldehydes and benzoic acids against campylobacter jejuni, escherichia coli, listeria monocytogenes, and salmonella enterica. Journal of Food Protection.v.66 (10) p.1811-1821 Interpretive Summary: As part of a broad effort to define the chemical basis for antimicrobial activities of different classes of natural products, we screened 70 benzaldehydes and benzoic acids substituted on the benzene ring with one, two, and three hydroxy and/or methoxy groups against the following four human pathogens reported to infect food: Escherichia coli O157:H7, Salmonella enterica, Campylobacter jejuni, and Listeria monocytogenes. The data suggest that the benzaldehydes are more active than the benzoic acids and that antimicrobial activities are influenced by both the number and position of the hydroxy and methoxy groups on the benzene ring. The ultimate goal of these studies is to develop food formulations that use some of the more active compounds to reduce pathogens in foods and feeds. The fact that many of the active compounds evaluated in the present study are soluble in water should facilitate their use in a variety of food systems.
Technical Abstract: We evaluated the bactericidal activities of 70 benzaldehydes and benzoic acids substituted in the benzene ring with zero, one, two, or three hydroxy (OH) and/or methoxy (OCH3) groups in a pH 7 buffer against Escherichia coli O157:H7, Salmonella enterica, Campylobacter jejuni, and Listeria monocytogenes in terms of the % of the sample that resulted in a 50% decrease in CFU (BA50). The following order of bactericidal activity was noted: tri-substituted OH>di-substituted-OH>mono-substituted-OH. For di-substituted derivatives, the 2-OH and 4-OH groups enhanced activities of benzaldehyde but not that of benzoic acid. Compounds with mixed OH and OCH3 groups exhibited variable results, i.e. in some cases the OCH3 groups enhanced activity and in others they had no effect. The ten most active compounds for C. jejuni (BA50, 0.0007-0.0093) were: 2-OH-5-OCH3-benzaldehyde, 3,4,5-tri-OH-benzaldehyde, 2-OH-4-OCH3-benzaldehyde, 3,4-di-OH-5-OCH3-benzaldehyde, 3,4-di-OH-benzaldehyde, 2,3,4-tri-OH-benzaldehyde, 3,4,5-tri-OH-benzoic acid, 4-OH-2,6-di-OCH3-benzaldehyde, 2,4,6-tri-OH-benzaldehyde, and 3,4,5-tri-OH-benzoate methyl ester. For S. enterica (BA50, 0.029-0.140): 2,3,4-tri-OH-benzaldehyde, 2,4,6-tri-OH-benzaldehyde, 3,4,5-tri-OH-benzoic acid, 4-OH-2,6-di-OCH3-benzaldehyde, 3,4,5-tri-OH-benzaldehyde, 2,5-di-OH-benzaldehyde, 2,3,4-tri-OH-benzoic acid, 2,4-di-OH-benzaldehyde, 2,3-di-OH-benzaldehyde, and 3-OCH3-benzaldehyde. For E. coli (BA50, 0.042-0.160): 3,4,5-tri-OH-benzaldehyde, 4-OH-2,6-OCH3-benzaldehyde, 2,3,4-tri-OH-benzaldehyde, 2,5-di-OH-benzaldehyde, 2,4,6-tri-OH-benzaldehyde, 2-OH-5-OCH3-benzaldehyde, 2,3-OH-benzaldehyde, 2,4-di-OH-benzaldehyde, 2-OH-benzaldehyde, and 3,5-di-OH-benzaldehyde. For L. monocytogenes (BA50, 0.009-0.38): 2,4,6-tri-OH-benzaldehyde, 2-OH-4-OCH3-benzaldehyde, 2,3-di-OH-benzaldehyde, 2,5-di-OH-benzaldehyde, 3,5-di-OH-benzaldehyde, 2-OH-3-OCH3-benzaldehyde, 2-OH-5-OCH3-benzaldehyde, 3,4,5-tri-OH-benzoate methyl ester, 2,3,4-tri-OH-benzaldehyde, and 5-OH-3,4-OCH3-benzaldehyde. These studies suggest possible new ways to protect foods against infection by human pathogens.