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Susceptibility of food‐borne bacteria to binary combinations of antimicrobials at selected a w and pH
Author(s) -
SantiestebanLópez A.,
Palou E.,
LópezMalo A.
Publication year - 2007
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2006.03092.x
Subject(s) - carvacrol , potassium sorbate , thymol , eugenol , antimicrobial , chemistry , food science , preservative , bacteria , minimum inhibitory concentration , antibacterial agent , microbiology and biotechnology , organic chemistry , essential oil , biochemistry , biology , antibiotics , genetics , sugar
Aim: To evaluate the antibacterial susceptibilities of food‐borne bacteria to individual and binary mixtures of a synthetic antimicrobial agent with a natural phenolic compound. Methods and Results: Antibacterial susceptibilities of Escherichia coli , Listeria innocua , Salmonella Typhimurium and Staphylococcus aureus to individual and binary mixtures of potassium sorbate with a phenolic compound (thymol, carvacrol, or eugenol) were evaluated, at selected water activity ( a w ; 0·99 or 0·97) and pH (5·5 or 4·5). The bacteria studied were susceptible to the action of the antimicrobials individually with minimal inhibitory concentrations that varied from 800‐ppm potassium sorbate for Staph. aureus at a w 0·99, and pH 5·5 to 100‐ppm thymol or carvacrol for the four studied bacteria at a w 0·97 and pH 4·5. Several binary mixtures of potassium sorbate with thymol, carvacrol or eugenol inhibited bacterial growth. Antimicrobial agent inhibitory concentrations in the mixture varied among bacteria, additionally depending on the a w and the pH tested. Conclusions: Synergistic binary mixtures with fractional inhibitory concentration index <0·6 include 100‐ or 200‐ppm potassium sorbate with 50‐ or 100‐ppm thymol, carvacrol or eugenol. Significance and Impact of the Study: The synergistic combinations could be useful in reducing the amounts of antimicrobials needed to inhibit growth, thus diminishing consumer concerns regarding chemical preservatives.