Antimicrobial and anti-biofilm activity of olive oil by-products against Campylobacter spp. isolated from chicken meat

Abstract

Background. Worldwide, poultry is considered the main source of food-related human campylobacteriosis, which is generally associated with the consumption of raw or undercooked chicken meat. Furthermore, Campylobacter develops biofilms that are resistant to environmental stress, antibiotics, and disinfectants and are becoming a major issue for the food industry, especially the poultry industry. This study investigated the antimicrobial and anti-biofilm properties of polyphenols found in spray-dried olive mill wastewater (OMWW- -SD) against Campylobacter strains isolated from chicken meat. Material and methods. OMWW-SD was produced by dehydration of olive mill wastewater polyphenolic extract. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for OMWW-SD were determined by microdilution method whereas the inhibitory effect of the OMWW-SD on biofilm formation and biofilm disaggregation was tested through crystal violet assay on polystyrene plates. Results. The phenolic profile of OMWW-SD mainly consisted of secoiridoid and hydroxycinnamic acid derivatives. Oleuropein-aglycone di-aldehyde (a secoiridoid derivative) was the major constituent, representing 72.5% of the total identified phenolic compounds. OMWW-SD showed a MIC ranging from 0.15 mg/mL to 0.3 mg/mL and a MBC of 0.3 mg/mL for all Campylobacter strains tested. The olive by-product extract tested was able, in vitro, to inhibit biofilm formation and to promote biofilm dispersion even at sub-MIC concentrations, with values ranging from 6% to 92% and from 4% to 83% at varying extract dilutions, respectively. Conclusion. OMWW-SD could be developed as a new anti-biofilm agent with potential to control Campylobacter in the food chain, especially in the poultry industry, thereby enhancing food safety.