<abstract xmlns="http://www.w3.org/1999/xhtml">
<sec id="j_jvetres-2022-0060_s_005"><h3>Introduction</h3><p>Heat treatment is indispensable in fish canning to provide an acceptable shelf life. Its optimisation reduces the risk of the presence of <italic>Clostridium botulinum</italic> spores, which could potentially cause botulism cases. This study evaluated canned fish samples for botulism neurotoxin (BoNT)-producing clostridia contamination and can bulging through microbiological contaminant growth. A new analytical approach was developed for detection of such clostridia and phenotypically similar species.</p></sec>
<sec id="j_jvetres-2022-0060_s_006"><h3>Material and Methods</h3><p>A total of 70 canned fish samples suspected of exhibiting bulging features were analysed. Culture methods were used to detect clostridia. The isolates obtained were evaluated on the basis of the exhibited phenotypic characteristics. Also, PCRs were used for the detection of genes determining BoNT production (non-toxic non-haemagglutinin (<italic>ntnh</italic>) genes) and the amplification of conservative 16S rDNA genes, which were Sanger sequenced. The obtained sequences were analysed using the Basic Local Alignment Search Tool.</p></sec>
<sec id="j_jvetres-2022-0060_s_007"><h3>Results</h3><p><italic>Clostridium</italic> genus species were isolated from 17 (24%) bulging and organoleptically changed samples. No <italic>ntnh</italic> genes were present in these isolates; however, sequencing confirmed the presence of <italic>C. sporogenes</italic>, a species with close affinity to <italic>C. botulinum</italic>.</p></sec>
<sec id="j_jvetres-2022-0060_s_008"><h3>Conclusion</h3><p>To eliminate the threat of foodborne botulism, laboratory diagnostic techniques must detect species of the <italic>Clostridium</italic> genus and elucidate their ability to produce BoNTs. Although <italic>Clostridium botulinum</italic> is the most common cause of botulism, the possibility may not be ignored that non-pathogenic <italic>Clostridium</italic> species may acquire botulinum toxigenicity. The similarity between the isolated strains of <italic>C. sporogenes</italic> and <italic>C. botulinum</italic> should be incorporated in the optimisation of heat treatment to guarantee a sterilised, microbiologically safe product.</p></sec>
</abstract>

IntroductionHeat treatment is indispensable in fish canning to provide an acceptable shelf life. Its optimisation reduces the risk of the presence of Clostridium botulinum spores, which could potentially cause botulism cases. This study evaluated canned fish samples for botulism neurotoxin (BoNT)-producing clostridia contamination and can bulging through microbiological contaminant growth. A new analytical approach was developed for detection of such clostridia and phenotypically similar species.
Material and MethodsA total of 70 canned fish samples suspected of exhibiting bulging features were analysed. Culture methods were used to detect clostridia. The isolates obtained were evaluated on the basis of the exhibited phenotypic characteristics. Also, PCRs were used for the detection of genes determining BoNT production (non-toxic non-haemagglutinin (ntnh) genes) and the amplification of conservative 16S rDNA genes, which were Sanger sequenced. The obtained sequences were analysed using the Basic Local Alignment Search Tool.
ResultsClostridium genus species were isolated from 17 (24%) bulging and organoleptically changed samples. No ntnh genes were present in these isolates; however, sequencing confirmed the presence of C. sporogenes, a species with close affinity to C. botulinum.
ConclusionTo eliminate the threat of foodborne botulism, laboratory diagnostic techniques must detect species of the Clostridium genus and elucidate their ability to produce BoNTs. Although Clostridium botulinum is the most common cause of botulism, the possibility may not be ignored that non-pathogenic Clostridium species may acquire botulinum toxigenicity. The similarity between the isolated strains of C. sporogenes and C. botulinum should be incorporated in the optimisation of heat treatment to guarantee a sterilised, microbiologically safe product.

Potential risk of botulinum neurotoxin -producing clostridia occurrence in canned fish

Journal of Veterinary Research

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

IntroductionHeat treatment is indispensable in fish canning to provide an acceptable shelf life. Its optimisation reduces the risk of the presence of...

Amplicon sample	Sequence ID	% Similarity	Similar sequence from the GenBank database
S1	MT356160.1	98.40	Clostridium sporogenes strain SM5 16S rRNA
S2	MT356160.1	99.25	Clostridium sporogenes strain SM5 16S rRNA
S3	MT356160.1	99.15	Clostridium sporogenes strain SM5 16S rRNA
S4	MT356160.1	99.43	Clostridium sporogenes strain SM5 16S rRNA
S5	MT356160.1	99.32	Clostridium sporogenes strain SM5 16S rRNA
S6	MT356160.1	99.51	Clostridium sporogenes strain SM5 16S rRNA

Potential risk of botulinum neurotoxin -producing clostridia occurrence in canned fish

Publié en ligne: 07 nov. 2022

Pages: 605 - 611

Reçu: 03 juin 2022

Accepté: 21 oct. 2022

DOI: https://doi.org/10.2478/jvetres-2022-0060

Mots clés
canned fish, microbiological contamination

© 2022 A. Jarosz et al. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

Fig. 2

Fig. 3

Results of the 16S rDNA gene identification of isolates from canned fish

Potential risk of botulinum neurotoxin -producing clostridia occurrence in canned fish

Publié en ligne: 07 nov. 2022

Pages: 605 - 611

Reçu: 03 juin 2022

Accepté: 21 oct. 2022

DOI: https://doi.org/10.2478/jvetres-2022-0060

Mots cléscanned fish, microbiological contamination

© 2022 A. Jarosz et al. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

Fig. 2

Fig. 3

Results of the 16S rDNA gene identification of isolates from canned fish

Mots clés
canned fish, microbiological contamination