Evaluation and identification of poly-microbial biofilms on natural green Gordal table olives

© 2015, Springer International Publishing Switzerland. This work examines the formation of poly-microbial communities adhered to the epidermis of natural green Gordal olives and the application of different methodologies for recovery and counting of the microorganisms embedded in olive biofilms. The fermentation process was physicochemical and microbiologically monitored for 90 days, at which, formation of true biofilms on the skin of fermented fruits was confirmed by scanning electron microscopy. Then, samples of olives were taken and treated with sonication, enzymes, mechanical homogenization with stomacher and ultrasonic bath for biofilm disaggregation. The use of the stomacher for 1 min was the most effective treatment to release the lactic acid bacteria (6.6 log10 cfu g−1), whereas sonication for 5 min was the most efficient method for quantification of yeasts (up to 3.5 log10 cfu g−1). Molecular identification of isolates obtained from natural Gordal olive biofilms revealed that Lactobacillus pentosus was the only species found among lactic acid bacteria, while Pichia membranifaciens was the dominant yeast species, with higher counts obtained for the bacteria.The research leading to these results has received funding from the Spanish Government (project OliFilm AGL-2013-48300-R: www.​olifilm.​science.​com.​es), and the Junta de Andalucía (through financial support to project P11-AGR-7051 and group AGR-125). A. Benítez and F.N. Arroyo-López wish to express thanks to the Spanish Government for their pre-doctoral fellowship and postdoctoral research contract (Ramón y Cajal), respectively. V. Romero-Gil would like also to thank the AgriFood Campus of International Excellence (ceiA3), Bank of Santander, Spanish Government and ‘Aloreña de Málaga’ Olive Manufacturing Association for her pre-doctoral fellowship (training program of Ph.D. in companies).Peer Reviewe