Reduction of carcinogens in fermented fish (pla-ra and pla-som) by heating

Research (Published online: 25-08-2023)

21. Reduction of carcinogens in fermented fish (pla-ra and pla-som) by heating

Atchara Artchayasawat, Pranee Sriraj, Thidarut Boonmars, Ratchadawan Aukkanimart, Ampas Wisetmora, Glenn N. Borlace, Parichart Boueroy, Benjamabhorn Pumhirunroj, Porntip Laummaunwai, Panaratana Rattanasuwan, Sirintip Boonjaraspinyo, Nattapon Ekobol, Opal Pitaksakulrat, and Wu Zhiliang

Veterinary World, 16(8): 1727-1735

Atchara Artchayasawat: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand; Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, 40002, Thailand.

Pranee Sriraj: Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, 40002, Thailand; Department of Traditional Medicine, Faculty of Natural Resources, Rajamangala University of Technology ISAN Sakon Nakhon Campus, Sakon Nakhon, 47160, Thailand.

Thidarut Boonmars: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand; Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, 40002, Thailand.

Ratchadawan Aukkanimart: Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, 40002, Thailand; Department of Traditional Medicine, Faculty of Natural Resources, Rajamangala University of Technology ISAN Sakon Nakhon Campus, Sakon Nakhon, 47160, Thailand.

Ampas Wisetmora: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand; Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, 40002, Thailand.

Glenn N. Borlace: Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand.

Parichart Boueroy: Department of Community Health, Faculty of Public Health, Kasetsart University Chalermphakiat Sakon Nakhon Province Campus, Sakon Nakhon, 47000, Thailand.

Benjamabhorn Pumhirunroj: Program in Animal Science, Faculty of Agricultural Technology, Sakon Nakhon Rajabhat University, Sakon Nakhon, 47000, Thailand.

Porntip Laummaunwai: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand.

Panaratana Rattanasuwan: Department of Anesthesiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand.

Sirintip Boonjaraspinyo: Department of Community Medicine, Family Medicine and Occupational Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand.

Nattapon Ekobol: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand; Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, 40002, Thailand.

Opal Pitaksakulrat: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand; Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, 40002, Thailand.

Wu Zhiliang: Department of Parasitology and Infectious Disease, Graduate School of Medicine, Gifu University, Japan.

Background and Aim: The risk factors for cholangiocarcinoma (CCA) are opisthorchiasis and the intake of a combination of nitroso compounds through the consumption of traditionally fermented fish, which is very popular in areas where liver flukes are endemic. The incidence of CCA remains high because this cultural habit of rural people has been altered. Therefore, decreasing nitrate and nitrite concentrations in fermented fish are an alternative approach to reducing the risk of CCA. Thus, this study aimed to reduce nitrate and nitrite concentrations in fermented foods by heating and investigated its effect on CCA development in a hamster model.

Materials and Methods: We used Association of Official Analytical Chemists method 973.31 to measure the nitrate and nitrite concentrations in both fermented fish (pla-ra [PR]) and pickled fish (pla-som [PS]) before and after boiling for 5 and 30 min, respectively. The same samples were fed to Opisthorchis viverrini (OV)-infected or -uninfected hamsters for 3 months. Thereafter, the hamsters’ liver and blood were collected for analysis.

Results: The levels of nitrates and nitrites in PS and PR significantly decreased following boiling for 5 and 30 min. The OV-PR and OV-PS groups showed dramatically increased numbers of inflammatory cells, fibrosis surrounding the bile duct, and focal fibrotic areas. However, after boiling the fermented dishes for 5 and 30 min, the extent of inflammatory cell infiltration and intensity of fibrosis in these groups were decreased.

Conclusion: Our findings suggest that boiling reduces nitrate and nitrite toxicity in fermented dishes, as evidenced by reduced hepatic inflammation. However, regardless of heating, kidney tissues are adversely affected when fermented meals are consumed daily.