Antimicrobial Effects of Wine: Separating the Role of Polyphenols, pH, Ethanol, and Other Wine Components

Abstract

While the antimicrobial effectiveness of wine is well documented, relative contributions of the wine components to its antimicrobial activity is controversial. To separate the role of wine phenolics, ethanol, and pH from other wine constituents, the antimicrobial effects of intact wine were compared to that of phenols-stripped wine, dealcoholized wine, ethanol, and low pH applied separately and in combination, against 2 common foodborne pathogens, Salmonella enterica serovar Enteritidis and Escherichia coli. All samples were biochemically characterized with respect to their total phenolics and resveratrol content, antioxidant capacity, ethanol content, and pH. Antioxidative activity of the samples corresponded to their total phenolics content. Except for respective controls, pH and ethanol content were similar in all samples. The order of antibacterial activity of the samples was: intact wine > phenols-stripped wine > dealcoholized wine > combination of ethanol and low pH > low pH > ethanol. Separate application of ethanol or low pH showed negligible antibacterial activity while their combination showed synergistic effect. Antibacterial activity of the samples could not be related to their total phenolics and resveratrol content, antioxidant capacity, ethanol content, or pH. Our study indicates that antimicrobial activity of complex solutions such as intact wine cannot be exclusively attributed to its phenolic or nonphenolic constituents, nor can the antimicrobial activity of wine be predicted on the basis of its particular components.

Agronomical and Chemical Effects of the Timing of Cluster Thinning on Pinot Noir (Clone 115) Grapes and Wines

“…Wine pH is tied intrinsically to a wine's microbial and oxidative stability, with lower pH values inhibiting (synergistically with ethanol) microbial growth [58] and increasing the ability of phenolics to protect the wine from premature oxidation [59]. There was a significant effect of thinning timing on wine pH, with bloom + 12 having lower wine pH relative to the control in accordance with the observed lowered fruit pH.…”

Wine consumption and intestinal redox homeostasis

“…Conversely, low doses of alcohol have long been known to exercise bactericidal activity, which is improved by the acid pH of wine; the activity against the gastrointestinal pathogens Salmonella enterica and E. coli was markedly increased in whole wine compared to either dealcoholized wine or ethanol alone, suggesting that suggesting that other substances in non-alcoholic fraction of wine might synergize the anti-bacterial effect of ethanol [52].…”

Nutrient Signaling: Evolutionary Origins of the Immune-Modulating Effects of Dietary Fat

“…Plant-derived phenolics also exert strong antimicrobial effects against oral pathogens, including Porphyromonas gingivalis; these compounds also inhibit the enzyme cyclooxygenase with strong anti-inflammatory effects (Sreenivasan and Gaffar 2008). The same pattern applies to resveratrol in red wine (Boban et al 2010) and to antimicrobial spices used in many cuisines . Commonly used spices have broad-spectrum antimicrobial effects, and their use by humans coincides with increased risk of bacterial contamination of food (Billing and Sherman 1998).…”