Distribution of bacteria in fish processing contact surfaces and biofilm formation of Raoultella ornithinolytica and Raoultella terrigena

Name: Adisara Tantasuttikul

LCSH: Kasetsart University -- Dissertations. Ph.D. (Food Science) 2019

Classification :.LCCS: QR100.8.B55

LCSH: Kasetsart University. -- Faculty of Food Science and Technology -- Dissertations

LCSH: Biofilms

LCSH: Bacteria

LCSH: Enterobacteriaceae

LCSH: Fishery processing

Abstract: Recently Raoultella spp. was found in the food plant environment and becomes the bacteria concerned due to the frequent spoilager and potential histamine producer in many kinds of fish products. A few information regarding to the properties of this bacteria, thus the objectives of this research aimed: 1) to investigate the presence of Raoultella spp. from the environment of fish process plants with the bacterial profile identified by MALDI−TOF, 2) to characterize and study the growth factors influencing the biofilm formation of R. ornithinolytica and R. terrigena, as well as the histamine production in tuna meat, and lastly 3) to investigate the cleaning of Raoultella biofilm by various chemicals. The results exhibited that among 1,089 isolates of bacteria adhered on surface in two fish processing plants, the majority was Gram−negative bacteria including Acinetobacter spp. (24−49%), Pseudomonas spp. (23−58%) and Myroides spp. (15%), only one isolate Raoultella was found. Many genera were the spoilager and several strains were the potent histamine producer such as Morganella spp. (10 isolates), Enterobacter spp. (11 isolates) and Proteus spp. (5 isolates). The growth characterization of R. ornithinolytica and R. terrigena culture in Tryptic Soy Broth (TSB) under conditions of pH (3, 4, 5, 6, 7, 8, 9, 10), temperature (4, 15, 20, 37, 40o C) and NaCl concentration (1%, 1.5%, 2.5%, 3.5%, 4.5%, 5.5%, 6.5%) were not significant different. Limitation for their growth were at: pH 3 and 10, 4 oC and 40o C and NaCl over 4.5%. The study of stressed Raoultella biofilm on stainless steel (SS) coupons cultured with 0.3 g/L TSB under various temperature conditions revealed that R. ornithinolytica and R. terrigena actively formed biofilm at 15o C. The mature biofilm expressed as the maximum extracellular polymeric substance (EPS) content produced by R. orinithinolytica at 15°C reached by 10 days, while R. terrigena reached by 25 days. Histamine production of two Raoultella spp. after artificially cross-contaminated SS coupons with cooked tuna meat revealed that the transfer rate about 68-74% caused the high histamine production at 37 °C within 12 hours. Abused temperature at 15°C also supported the growth and histamine production. Lastly when R. ornithinolytica and R. terrigena biofilm exposed to 3 types of chemicals (sodium hypochlorite (NaOCl) 50 and 100 mL/L), hydrogen peroxide (H2O2) 1 and 2 % and ozonated water (0.5 and 1.0 mg/mL)), it revealed that NaOCl was able to eliminate Raoultella spp. biofilm at 50 mL/L within 5 minutes while ozone had less efficacy to kill biofilm cells. H2O2 at the concentration of 1% and 2% succeeded to apply as pre-treatment for biofilm elimination. This finding about the properties of Raoultella spp. is the basic information which will be useful for design control measure to prevent the contamination of these species regarding seafood plant sanitation.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Warapa Mahakarnchanakul

Role: Thesis Advisor

Name: Kullanart Tongkhao

Role: Thesis CO-Advisor

Name: Tanaboon Sajjaanantakul

Role: Thesis CO-Advisor

Name: Pongtep Wilaipun

Role: Thesis CO-Advisor

Role: Thesis CO-Advisor

Created: 2019

Modified: 2025-06-27

Issued: 2025-06-27

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2562/adisara-tan-all.pdf

CallNumber: QR100.8.B55 .A35

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degraee

Descipline: Food Science

Grantor: Kasetsart University

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