Chemical Composition and Comprehensive Antimicrobial Activity of an Ethanolic Extract of Propolis from Tunisia

Abstract

In the present study, the chemical composition and the in vitro antimicrobial and antibiofilm activity of an ethanolic extract of propolis (EEP) from Tunisia against different ATCC and wild bacterial strains were evaluated. In situ antimicrobial activity and sensory influence of different EEP concentrations (0.5% and 1%), also in combination with 1% vinegar, were evaluated in chilled vacuum-packed salmon tartare. Furthermore, a challenge test was performed on salmon tartare experimentally contaminated with Listeria monocytogenes and treated with the different EEP formulations. The in vitro antimicrobial and antibiofilm activity was observed only against Gram-positive bacteria, such as L. monocytogenes and S. aureus, both ATCC and wild. Results of the in situ analyses revealed significant antimicrobial activity against aerobic colonies, lactic acid bacteria, Enterobacteriaceae and Pseudomonas spp. only when the EEP was used at 1% and in combination with 1% vinegar. The 1% EEP in combination with 1% vinegar was the most effective treatment also against L. monocytogenes, although 0.5% and 1% EEP used alone also showed antilisterial effects. After 7 days of storage, the sensory influence on odor, taste and color of salmon tartare was negligible for all EEP formulations. In this background, results obtained confirmed the antimicrobial efficacy of propolis which could be proposed as a suitable biopreservative to ensure safety and improve the quality of food.

Exploring Propolis as a Sustainable Bio-Preservative Agent to Control Foodborne Pathogens in Vacuum-Packed Cooked Ham

“…Our results evidence the high sensitivity towards propolis, as shown by the vast inhibition halos and the low MIC and MBC values obtained in the inoculated strains. These findings are in agreement with other works that reflect similar conclusions concerning the bacterial behavior of L. monocytogenes and S. aureus [44] and similarly with sporulated bacteria such as B. cereus [45] and C. sporogenes [46] at in vitro conditions [43].…”

“…These results suggest that neither other preservatives nor propolis might control Listeria's growth in the event of post-heat treatment contamination during its refrigerated storage. This discrepancy with the results of the MIC values for L. monocytogenes is probably due to the interference of the bioactive compounds with other food components and the effect of the processing (heat treatment) [43]. The same behavior for L. monocytogenes has been reported in another study investigating the bio-preservative properties of plant extracts in meat products after heat treatment [44,54].…”

“…Most flavonoids and phenolic acids identified in the selected propolis exhibited biological activity against Gram-positive and Gram-negative food-borne pathogens, as displayed by the low minimum inhibition concentrations [35]. Some flavonoids have even been considered for their effect on C. botulinum toxin production [14,43].…”

“…Propolis has been incorporated into meat products such as sausages [46], beef patties, salami [47], raw meat [39,48], and many dairy products such as ice cream, milk, and cheese [4,[49][50][51]. However, when referring to foods subjected to heat treatment, current works only considered plant powder extracts as an alternative [14,39,43,52]. In this context, when considering the microbial behavior in cooked ham formulations, our results indicated that EEP can control the growth of sporulating bacteria (C. sporogenes and B. cereus) and S. aureus at low concentrations.…”

Essential Oil Emulsion from Caper (Capparis spinosa L.) Leaves: Exploration of Its Antibacterial and Antioxidant Properties for Possible Application as a Natural Food Preservative

“…In this context, essential oils extracted from various parts of plants and herbs are being extensively investigated for their potential application in the food industry [ 1 , 2 , 3 , 4 , 5 ]. Indeed, essential oils exhibit interesting biological activities, including antimicrobial, antioxidant, and anticancer properties, and are generally recognised as safe (GRAS) substances for human consumption by the Food and Drug Administration [ 6 ].…”