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Institute of Chemical Technology Prague Department of Food Preservation and Meat Technology. Asaia bogorensis biofilm in beverage produce. Petra Sedláčková. Reversible adherence. What is biofilm ?. Bulk fluid. (c). (a). (b). Solid surface. Irreversible adherence. Bulk fluid.
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Institute of Chemical Technology Prague Department of Food Preservation and Meat Technology Asaia bogorensis biofilm in beverage produce Petra Sedláčková
Reversible adherence • What is biofilm? Bulk fluid (c) (a) (b) Solid surface • Irreversible adherence Bulk fluid polysaccharide (a) (b) Solid surface
Polyethylene surface • Asaia bogorensis biofilm on polyethylene surface (electron microscopy)
Previous work • microorganisms • Pseudomonas spp (model microorganism) • Asaia bogorensis • biofilm was grown on • polyethylene surface • polystyrene surface • stainless steel • chemical sanitizers • peracetic acid • sodium hypochlorite • quaternary ammonium compounds • iodine based compounds • bromacetic acid
Asaia bogorensis • gram-negative, aerobic bacteria • catalase positive, oxidase negative • growth: • pale pink, smooth colonies • small (approximately 1 – 2 mm in diameter) • 20 – 30°C (failed to growth at 37°C) • pH 3.0
Biofilm preparation • Culture of Gram-negative Asaia bogorensis was kept on PCA agar (30°C, 48 hr). • Suspension of bacteria was prepared in nutrientbroth – 2 % glucose, 0.5 % yeast extract powder. • The inocula used for biofilm formation contained about 106 CFU*cm-3. • Biofilm was grown on surface of polyethylene tube for 6 days.
Chemical sanitizers • peracetic acid 15 - <30% • hydrogen-peroxide 15 - <30%,acetic acid 15 - <30% • 8 - 22°C 0.10 – 0.15% 5 – 10 min • quaternary ammonium compounds 15 - < 30%, • sodium carbonate 1 - < 5%, EDTA < 1% • 8 – 20°C 0.1 – 0.3% 20 – 60 min • sodium hypochlorite 5 - <15% • cold conditions 0.1 – 0.2% 10 – 20 min
Evaluating of the efficacy of sanitizers • surface test - biofilm • bacteria were scraped from test surfaces witha cotton-wool swab transferred into test tube containing 10 ml physiological solution stirred for1 min to release the cells into the solution • the samples were cultivated at 30°C on PCA agar for 48 hr
Efficacy of QAC (quaternary ammonium compounds) on 6-day-old biofilm of Asaia bogorensis grown under the dynamic conditions. Effect of concentration and exposure time of QAC.
Efficacy of peracetic acidon 6-day-old biofilm of Asaia bogorensis grown under the dynamic conditions. Effect of concentration and exposure time of peracetic acid.
Efficacy of sodium hypochlorite on 6-day-old biofilm of Asaia bogorensis grown under the dynamic conditions. Effect of concentration and exposure time of sodium hypochlorite.
Conclusion • It is supposed that the adherence of Asaia bogorensis under the dynamic conditions is better than adherence under the static conditions. • Biofilm prepared under the dynamic conditions is more resistant to sanitizing process than biofilm prepared under the static conditions. • The sanitizer with peracetic acid as an active component is more effective than the others tested solutions.