<![CDATA[Graphical Abstract Highlight Research The biofilm formation of Raoultella ornithinolytica on a stainless steel surface was analyzed Longer duration of hot water immersion leading to a higher reduction of Raoultella ornithinolytica biofilm on stainless steel surface. Longer duration of nanochitosan exposure leading to a higher reduction of Raoultella ornithinolytica biofilm on stainless steel surface The combination treatment of hot water immersion and nanochitosan shows higher efficacy to reduce Raoultella ornithinolytica biofilm on stainless steel surface compare to sodium hypochlorite treatment. Abstract The equipment surfaces in food processing industries have the potential to contaminate products. Bacteria on a surface are able to form a biofilm. This study aimed to determine the effect of a combination treatment using hot water immersion and nanochitosan on the reduction of R. ornithinolytica’s biofilm on stainless steel surfaces. R. ornithinolytica was applied to a stainless steel surface, incubated at 30oC for 48 hours, and tested for its reduction using hot water immersion treatment with different times. The best result from this treatment was when it was used in combination. The viability of cells was determined using a swab and the total plate count method. A scanning electron microscope was used for qualitative observations of biofilm formed on stainless steel before and after sanitation. The result showed that 10 minutes of hot water immersion resulted in significant R. ornithinolytica biofilm reduction compared to 5 minutes of treatment (p<0.05). Furthermore, the combination treatment of 10 minutes of hot water with 15 minutes of nanochitosan (0.1%) immersion showed the highest percent reduction of R. ornithinolytica biofilm (p<0.05). The ability of the combination treatment to eliminate R. ornithinolytica biofilms is equivalent to or even better than sodium hypochlorite treatment.]]>
