Survival of foodborne pathogens in unripe grape products

• Unripe grape products (UGPs) inoculated with food borne pathogens.
• None of the tested pathogens could survive in UGPs.
• UGPs inhibited pathogens (2 log CFU/mL) in 5 min or (6 log CFU/mL) in 15 min.
• Inhibitory effectS of UGPs mainly depend on their organic acid content.
• UGP are microbiologically safe products and they have self-protection system.

Antibacterial effects of unripe grape products (verjuice and sour grape sauce) which are particularly rich in antioxidants and organic acids were evaluated. Survival of Escherichia coli, Listeria monocytogenes, Salmonella Typhimurium and Staphylococcus aureus which were inoculated in unripe grape products at different inoculum doses (2 and 6 log CFU/mL) was determined. All the samples were kept at room temperature (approximately 25 °C) for 0, 5, 15 and 30 min after inoculation with pathogens, separately. The unripe grape products which were inoculated at low inoculum dose inhibited all tested pathogens in 5 min, while it took 15 min for high inoculum dose. The pH, titratable acidity (tartaric acid %) and total sugar content values of the samples were between 2.14–2.74, 2.29–7.10% and 1.19–17.65 g/L, respectively. It was concluded that unripe grape products are microbiologically safe products and they have self-protection systems even when they were contaminated with pathogens at high levels.