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. 2023 Aug;16(8):1727-1735.
doi: 10.14202/vetworld.2023.1727-1735. Epub 2023 Aug 25.

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

Atchara Artchayasawat  1   2 , Pranee Sriraj  2   3 , Thidarut Boonmars  1   2 , Ratchadawan Aukkanimart  2   3 , Ampas Wisetmora  1   2 , Glenn N Borlace  4 , Parichart Boueroy  5 , Benjamabhorn Pumhirunroj  6 , Porntip Laummaunwai  1 , Panaratana Rattanasuwan  7 , Sirintip Boonjaraspinyo  8 , Nattapon Ekobol  1   2 , Opal Pitaksakulrat  1   2 , Wu Zhiliang  9
Affiliations

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

Atchara Artchayasawat et al. Vet World. 2023 Aug.

Abstract

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.

Keywords: cholangiocarcinoma; fish; liver flukes; opisthorchiasis.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure-1
Figure-1
Histopathological changes in the hepatobiliary system of the experimental groups. (a and b) Normal: Untreated hamster, (c) N-PR=Normal hamsters feed the raw fermented fish, (d) N-PS=Normal hamsters feed the raw pickled fish, (e) N-PR5=Normal hamsters feed the fermented fish with boiling for 5 min, (f) N-PS5=Normal hamsters feed the pickled fish with boiling for 5 min, (g) N-PR30=Normal hamsters feed the fermented fish with boiling for 30 min, and (h) N-PS30=Normal hamsters feed the pickled fish with boiling for 30 min, *Inflammatory cells aggregation.
Figure-2
Figure-2
Histopathological changes in the hepatobiliary system of the experimental groups. (a and b) OV=Hamster infected with Opisthorchis viverrini, (c and d) OV-PR=Opisthorchiasis’s hamsters feed the fermented fish, (e and f) OV-PR5=opisthorchiasis’s hamsters feed the fermented fish with boiling for 5 min, (g and h) OV-PR30=Opisthorchiasis’s hamsters feed the fermented fish with boiling for 30 min, P=Parasite (O. viverrini) in bile duct, *inflammatory cells aggregation.
Figure-3
Figure-3
Histopathological changes in the hepatobiliary system of the experimental groups. (a and b) OV=Hamster infected with Opisthorchis viverrini, (c and d) OV-PS=Opisthorchiasis’s hamsters feed the pickled fish, (e and f) OV-PS5=Opisthorchiasis’s hamsters feed the boiled pickled fish for 5 min, and (g and h) OV-PS30=Opisthorchiasis’s hamsters feed the boiled pickled fish for 30 min, P=Parasite (O. viverrini) in bile duct, *inflammatory cells aggregation.
Figure-4
Figure-4
Fibrosis in the hepatobiliary system of the experimental groups. (a and b) Normal=Uninfected OV hamster, (c and d) OV=Hamster infected with Opisthorchis viverrini, (e and f) OV-PR=Opisthorchiasis’s hamsters feed the fermented fish, (g and h) OV-PR5=Opisthorchiasis’s hamsters feed the fermented fish with boiling for 5 min, and (i and j) OV-PR30=Opisthorchiasis’s hamsters feed the fermented fish with boiling for 30 min, P=Parasite (O. viverrini) in bile duct, *fibrosis.
Figure-5
Figure-5
Fibrosis in the hepatobiliary system of the experimental groups. (a and b) Normal=Uninfected OV hamster, (c and d) OV=Hamster infected with Opisthorchis viverrini, (e and f) OV-PS=Opisthorchiasis’s hamsters feed the pickled fish, (g and h) OV-PS5=Opisthorchiasis’s hamsters feed the pickled fish with boiling for 5 min, and (i and j) OV-PS30=Opisthorchiasis’s hamsters feed the pickled fish with boiling for 30 min, P=Parasite (O. viverrini) in bile duct, *fibrosis.
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References

    1. Perakanya P, Ungcharoen R, Worrabannakorn S, Ongarj P, Artchayasawat A, Boonmars T, Boueroy P. Prevalence and risk factors of Opisthorchis viverrini infection in Sakon Nakhon province, Thailand. Trop. Med. Infect. Dis. 2022;7(10):313. - PMC - PubMed
    1. IARC. Infection with liver flukes (Opisthorchis viverrini, Opisthorchis felineus and Clonorchis sinensis) IARC Monogr. Eval. Carcinog. Risks Hum. 1994;61:121–175. - PMC - PubMed
    1. Sripa B, Suwannatrai A.T, Sayasone S, Do D.T, Khieu V, Yang Y. Current status of human liver fluke infections in the Greater Mekong Subregion. Acta Trop. 2021;224(12):106133. - PubMed
    1. IARC. Ingested nitrate and nitrite, and cyanobacterial peptide toxins. In:IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, No. 94. IARC, France. 2010:1–412. - PMC - PubMed
    1. Lebrun S, Van Nieuwenhuysen T, Crevecoeur S, Vanleyssem R, Thimister J, Denayer S, Jeuge S, Daube G, Clinquarta A, Fremaux B. Influence of reduced levels or suppression of sodium nitrite on the outgrowth and toxinogenesis of psychrotrophic Clostridium botulinum Group II type B in cooked ham. Int. J. Food Microbiol. 2020;334(23):108853. - PubMed

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