Abstract
The present study aimed at determining the histamine production capacity of Gram (+) and Gram (−) bacteria isolated from Octopus maya, along with identifying the presence of amino acid decarboxylase genes. Of the total 80 psychrotrophic microorganisms, 32 strains were identified as histamine-forming bacteria. The recombinant DNA technique was used for genotypic identification of histidine (hdc), ornithine (odc), and lysine decarboxylases (ldc) genes. Thirty-two strains were able to produce 60–100 ppm in trypticase soy broth with 1.0% l-histidine after 6 h at 20 °C. NR6B showed 98% homology with Hafnia alvei. NR73 represented 18.8% of the total isolates and showed 98% homology with Enterobacter xianfengensis and Enterobacter cloacae. NR6A represented 6% of the total isolates, which were identified as Lactococcus sp. The hdc gen from NR6B showed 100% identity with hdc from Morganella morganii; ldc showed 97.7% identity with ldc from Citrobacter freundii. The Odc gene was detected only in NR73 and showed 100% identity with Enterobacter sp. All the isolated were identified as weak histamine–former. The ingestion of a food containing small amounts of histamine has little effect on humans; however, the formation of biogenic amines is often considered as an indicator of hygienic quality; this emphasizes the importance of improving good management practices and storage.
Highlights
Mexico ranks among the top 10 exporters of octopus to the United States, representing approximately 13% of the market
Of a total of 80 microorganisms isolated from the edible octopus’ tissues, three bacterial genera coded as NR6A, NR6B, and NR73 were found to be histamine producers
NR73 represented 18.8% of the total isolates and 15 of them had 98% homology with Enterobacter xiangfangensis (NR_126208.1) and Enterobacter cloacae (NR_118568.1)
Summary
Mexico ranks among the top 10 exporters of octopus to the United States, representing approximately 13% of the market. The extraction is done in a small-scale fleet with vessels between 8 and 10 m in length near the coastal areas (2–5-fathom depth) whereby the organisms have a high microbial load on the surface of the skin at the time of capture [2]. These daily trip-boats are not well equipped for cold storage, which renders the octopus a highly perishable product even in subsequent refrigerated storage. Since fish handling practices are critical with regard to BAs production, histamine was defined as a chemical hazard regulated by the US Food and Drug
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