Öz

Mikroorganizmaların gıdaların temas ettikleri yüzeylere tutunması ve devamında biyofilm üretmeleri, ekipman hasarına, gıda bozulmalarına ve gıda kaynaklı hastalıklara neden olmaktadır. Gıdaların işlendiği çevrelerdeki biyofilmler rutin dezenfektanlara ve sanitasyon işlemlerine direnç gösterebilmektedir. Gıda biyofilmlerinin neden oldukları riskleri azaltmak adına çok sayıda çalışma yürütülmüştür. Bu bağlamda elektroliz, ucuz ve etkili bir yaklaşım olması itibariyle son zamanlarda araştırmacıların odağında bulunmaktadır. İlgili çalışmada önemli gıda patojenleri olan Escherichia coli, Salmonella Typhimurium ve Staphylococcus aureus biyofilmlerinin düşük elektrik akımı ile giderimi (eradikasyon) değerlendirilmiştir. Deneysel çalışmalar, biyofilm örneklerinin geliştirileceği metalik yüzeylerin entegre edilebildiği elektrotları ihtiva eden ve kolaylıkla kurulabilir elektroliz düzeneğinde gerçekleştirilmiştir. 2M NaCl çözeltisi tercih edilerek gerçekleştirilen elektroliz işlemiyle (10 V, 0.3 A, 1, 2 ve 5 dakika süresince) paslanmaz çelik yüzeyler üzerindeki E. coli ve S. Typhimurium biyofilm hücreleri bütünüyle elimine edilirken, S. aureus biyofilm hücrelerinin sayısında önemli ölçüde bir azalma saptanmıştır (2.5 log azalma). Biyofilm hücrelerindeki canlılık koloni sayım yöntemiyle kontrol edilmiştir. Ancak biyofilm matriks kalıntılarını yüzeyden bütünüyle temizlemek tercih edilen elektroliz prosedürüyle mümkün olmamıştır. İşlemden sonra yüzeyde kalan matriks yapıları kristal viyole bağlanma uygulamasıyla gösterilmiştir. Ucuz ve kolay uygulanabilir bir işlem olması itibariyle elektrolizin ve onun sonucunda elektrolit tampondaki reaksiyonlar sonucunda elde edilen biyosidal ajanların gıda endüstrisinde biyofilmler mücadelede kullanılabileceği açıkça anlaşılmıştır.

Anahtar Kelimeler

• Biyofilm
• Elektroliz
• Escherichia coli
• Salmonella Typhimurium
• Staphylococcus aureus

Reduction of Salmonella Typhimurium, Escherichia coli, and Staphylococcus aureus Biofilms by Electrolysis

Öz

Adherence of microorganisms to food contact surfaces and subsequent biofilm formation leads to equipment damage, food spoilage, and foodborne diseases. Biofilms in food processing plants may exhibit resistance to routine disinfectants and sanitation procedures. Extensive studies have been conducted to reduce the risks of food biofilms. Since electrolysis is an inexpensive and effective approach, it has recently become the focus of interest among researchers in this context. In the related study, the removal (eradication) of major food pathogens such as Escherichia coli, Salmonella Typhimurium and Staphylococcus aureus biofilms was evaluated using low electric current. Experimental studies were conducted in an easy-to-install electrolysis setup containing electrodes capable of integrating metal surfaces on which biofilms develop. E. coli and S. Typhimurium biofilm cells on stainless steel surfaces were eliminated, while a significant decrease (2.5 log reduction) in the number of S. aureus biofilm cells was observed in the electrolysis process performed in 2M NaCl solution (10 V, 0.3 A, 1, 2 and 5 min). The viability of biofilm cells was controlled using colony count method. However, the removal of biofilm matrix residues from the surface was not possible with the preferred electrolysis procedure. The biofilm matrix remaining on the surface after the procedure was detected by the crystal violet binding assay.
Being a low-cost and easy-to-use process, it became clear that electrolysis and the resulting biocidal agents produced by the reactions in the electrolyte buffer can be used in the food industry to control biofilms.

Anahtar Kelimeler

• Biofilm
• Electrolysis
• Escherichia coli
• Salmonella Typhimurium
• Staphylococcus aureus

Kaynakça

1. [1] Sutherland, I.W., The biofilm matrix–an immobilized but dynamic microbial environment, Trends in Microbiology, 9(5), 222-227, 2001.
2. [2] Mizan, M.F.R., Jahid, I.K., Ha, S.D., Microbial biofilms in seafood: a food-hygiene challenge, Food Microbiology, 49, 41-55, 2015.
3. [3] Poulsen, L.V., Microbial biofilm in food processing, LWT-Food Science and Technology, 32(6), 321-326, 2001.
4. [4] Brooks, J.D., Flint, S.H., Biofilms in the food industry: problems and potential solutions, International Journal of Food Science & Technology, 43(12), 2163-2176, 2008.
5. [5] Chmielewski, R.A.N., Frank, J.F., Biofilm formation and control in food processing facilities, Comprehensive Reviews in Food Science and Food Safety, 2(1), 22-32, 2003.
6. [6] Simões, M., Simões, L.C., Vieira, M.J., A review of current and emergent biofilm control strategies, LWT-Food Science and Technology, 43(4), 573-583, 2010.
7. [7] Jahid, I.K., Ha, S.D., A review of microbial biofilms of produce: future challenge to food safety, Food Science and Biotechnology, 21(2), 299-316, 2012.
8. [8] Srey, S., Jahid, I.K., Ha, S.D., Biofilm formation in food industries: a food safety concern, Food Control, 31(2), 572-585, 2013.

9. [9] Lewandowski, Z., Beyenal, H., Fundamentals of biofilm research, CRC Press. Boca Raton, FL. 2014.
10. [10] Rabinovitch, C., Stewart, P.S., Removal and inactivation of Staphylococcus epidermidis biofilms by electrolysis, Applied and Environmental Microbiology, 72(9), 6364-6366, 2006.
11. [11] Liu, W.K., Brown, M.R., Elliott, T.S., Mechanisms of the bactericidal activity of low amperage electric current (DC), The Journal of Antimicrobial Chemotherapy, 39(6), 687-695, 2001.
12. [12] Stoodley, P., deBeer, D., Lappin-Scott, H.M., Influence of electric fields and pH on biofilm structure as related to the bioelectric effect, Antimicrobial Agents and Chemotherapy, 41(9), 1876-1879, 1997.
13. [13] Poortinga, A.T., Smit, J., van der Mei, H.C., Busscher, H.J., Electric field induced desorption of bacteria from a conditioning film covered substratum, Biotechnology and Bioengineering, 76(4), 395-399, 2001.
14. [14] Hong, S.H., Jeong, J., Shim, S., Kang, H., Kwon, S., Ahn, K.H., Yoon, J., Effect of electric currents on bacterial detachment and inactivation, Biotechnology and Bioengineering, 100(2), 379-386, 2008.
15. [15] Stewart, P.S., G.A. McFeters, C.T., J.D., Bryers (ed.), Huang, Biofilm control by antimicrobial agents, Biofilms II: process analysis and applications. Wiley-Liss, New York, N.Y., 373p-405p, 2000.
16. [16] Lim, T.K., Murakami, T., Tsuboi, M., Yamashita, K., Matsunaga, T., Preparation of a colored conductive paint electrode for electrochemical inactivation of bacteria, Biotechnology and Bioengineering, 81(3), 299-304, 2003.
17. [17] Stewart, P.S., Wattanakaroon, W., Goodrum, L., Fortun, S.M., McLeod, B.R., Electrolytic generation of oxygen partially explains electrical enhancement of tobramycin efficacy against Pseudomonas aeruginosa Biofilm, Antimicrobial Agents and Chemotherapy, 43(2), 292-296, 1999.
18. [18] Kumar, C.G., Anand, S.K., Significance of microbial biofilms in food industry: a review, International Journal of Food Microbiology, 42(1-2), 9-27, 1998.
19. [19] Crémet, L., Corvec, S., Batard, E., Auger, M., Lopez, I., Pagniez, F., Caroff, N., Comparison of three methods to study biofilm formation by clinical strains of Escherichia coli, Diagnostic Microbiology and Infectious Disease, 75(3), 252-255, 2013.
20. [20] Vestby, L.K., Møretrø, T., Langsrud, S., Heir, E., Nesse, L.L., Biofilm forming abilities of Salmonella are correlated with persistence in fish meal-and feed factories, BMC Veterinary Research, 5(1), 20, 2009.
21. [21] Onbas, T., Osmanagaoglu, O., Kiran, F., Potential properties of Lactobacillus plantarum F-10 as a Bio-control strategy for wound infections, Probiotics and Antimicrobial Proteins, 11(4), 1110-1123, 2018.
22. [22] Istanbullu, O., Babauta, J., Duc Nguyen, H., Beyenal, H., Electrochemical biofilm control: mechanism of action, Biofouling, 28(8), 769-778, 2012.
23. [23] Stepanović, S., Vuković, D., Dakić, I., Savić, B., Švabić-Vlahović, M., A modified microtiter-plate test for quantification of staphylococcal biofilm formation, Journal of Microbiological Methods, 40(2), 175-179, 2000.
24. [24] Sultana, S.T., Babauta, J.T., Beyenal, H., Electrochemical biofilm control: a review, Biofouling, 31(9-10), 745-758, 2015.
25. [25] Dhar, H.P., Bockris, J.O., Lewis, D.H., Electrochemical inactivation of marine bacteria, Journal of the Electrochemical Society, 128(1), 229, 1981.
26. [26] Ueda, S, Kuwabara, Y., Susceptibility of biofilm Escherichia coli, Salmonella enteritidis and Staphylococcus aureus to detergents and sanitizers, Biocontrol Science 12(4), 149-153, 2007.
27. [27] Sandvik, E.L., McLeod, B.R., Parker, A.E., Stewart, P.S., Direct electric current treatment under physiologic saline conditions kills Staphylococcus epidermidis biofilms via electrolytic generation of hypochlorous acid, PloS one, 8(2), e55118, 2013.
28. [28] Giladi, M., Porat, Y., Blatt, A., Shmueli, E., Wasserman, Y., Kirson, E.D., and Palti, Y., Microbial growth inhibition by alternating electric fields in mice with Pseudomonas aeruginosa lung infection, Antimicrobial Agents and Chemotherapy, 54(8), 3212-3218, 2010.
29. [29] Caubet, R., Pedarros-Caubet, F., Chu, M., Freye, E., de Belem Rodrigues, M., Moreau, J.M., Ellison, W.J., A radio frequency electric current enhances antibiotic efficacy against bacterial biofilms, Antimicrobial Agents and Chemotherapy, 48(12), 4662-4664, 2004.
30. [30] Del Pozo, J.L., Rouse, M.S., Patel, R., Bioelectric effect and bacterial biofilms. A systematic review, The International Journal of Artificial Organs, 31(9), 786-795, 2008.
31. [31] Del Pozo, J.L., Rouse, M.S., Euba, G., Greenwood-Quaintance, K.E., Mandrekar, J.N., Steckelberg, J.M., Patel, R., Prevention of Staphylococcus epidermidis biofilm formation using electrical current, Journal of Applied Biomaterials & Functional Materials, 12(2), 81-83, 2014.
32. [32] Flemming, H.C., Wingender, J., The biofilm matrix, Nature Reviews Microbiology, 8(9), 623-633, 2010.
33. [33] Holah, J.T., Thorpe, R.H., Cleanability in relation to bacterial retention on unused and abraded domestic sink materials, Journal of Applied Bacteriology, 69(4), 599-608, 1990.
34. [34] Van Houdt, R., Michiels, C.W., Biofilm formation and the food industry, a focus on the bacterial outer surface, Journal of Applied Microbiology, 109(4), 1117-1131, 2010.
35. [35] Boyd, R.D., Cole, D., Rowe, D., Verran, J., Paul, A.J., West, R.H., Cleanability of soiled stainless steel as studied by atomic force microscopy and time of flight secondary ion mass spectrometry, Journal of Food Protection, 64(1), 87-93, 2001.