Broad-spectrum of antimicrobial properties of commercial wines from different Vitis vinifera L. varieties

Chemical Profile and Antibacterial Activity of Vitis vinifera L. cv Graciano Pomace Extracts Obtained by Green Supercritical CO2 Extraction Method Against Multidrug-Resistant Escherichia coli Strains

The objectives of this study were to obtain and characterise polyphenolic extracts from red grape pomace of Vitis vinifera L. cv Graciano via conventional solvent extraction (SE) and green supercritical fluid extraction (SFE) and to evaluate their in vitro antibacterial activity against susceptible and multidrug-resistant Escherichia coli strains of intestinal origin. The SE and SFE methods were optimised, and ultra-performance liquid chromatography/mass spectrometry (UPLC/QqQ-MS/MS) analysis revealed 38 phenolic compounds in the SE sample, with anthocyanins being the predominant polyphenols, and 21 phenolic compounds in the SFE samples, among which hydroxybenzoic acids and flavonols were the predominant compounds. The SE and SFE samples showed antibacterial activity against both antibiotic-susceptible and -resistant E. coli strains, and minimal inhibitory concentration values were in the range of 1-4 mg/mL. The activity was bacteriostatic in all cases, and it was shown that a higher content of total polyphenols correlated with a higher antibacterial activity of the extracts. This study shows that red grape pomace of Vitis vinifera L. cv. Graciano is a rich source of bioactive phenolic compounds that can become an important feedstock for additives and other upgraded products of biotechnological interest, which can help to modulate intestinal microbiota and combat bacterial antibiotic resistance.

Red Wine and Garlic as a Possible Alternative to Minimize the Use of Nitrite for Controlling Clostridium Sporogenes and Salmonella in a Cured Sausage: Safety and Sensory Implications

The use of nitrite in meat products has been questioned due to its potential association with colon cancer. This work aimed to evaluate the behavior of Clostridium sporogenes (used as a surrogate for Cl. botulinum) and Salmonella in a dry-cured sausage, chouriço, made with and without nitrite and nitrate or with red wine and garlic, and to study the sensory implications through a consumer test. The survival of Cl. sporogenes and Salmonella was determined mainly by the reduction in water activity (aw), but the use of wine or wine and garlic contributed to the control of Salmonella during processing. The challenge test with Cl. sporogenes revealed no effect of the curing salts, wine, or garlic on the population of this microorganism. The use of curing salts resulted in a more reddish color that was recognized by the consumer as over-cured and artificial when compared with chouriço made with wine or wine and garlic, which were better rated in the hedonic test. In cured sausages of small caliber, the use of nitrite might be reconsidered, as the values of aw necessary to inhibit Clostridium toxinogenesis and growth are achieved rapidly.