Microbiota cultivável produtora de histamina associada com a superfície e brânquias de cavalas frescas (Scomberomorus cavalla)

Abstract

Studies on histamine-producing bacteria (HPB) in fish are restricted to species from temperate regions, with little information on HPB in tropical fish. The aim of this work was to analyze the abundance of HPB in relation to the cultivable heterotrophic bacteria (CHB) present in superficial mucus from the skin and gills of the mackerel (Scomberomorus cavalla). Four samplings were made (May to August 2017), at the Fish Market, in the Mucuripe District in Fortaleza-CE. Plate Count Agar was used to quantify CHB and differential culture medium for HPB. In a differential medium, the total number of colonies was counted (HPBt) and the colonies with purple staining and halo, resulting from the increase in pH after histamine formation (HPBh). The numbers of CHB (4.52 Log UFC/cm2 ) and HPBh (4.16 Log UFC/cm2 ) of mucus from the skin of the mackerel didn’t present significant difference (p ≤ 0.05). In gills, the number of HPBh (6.20 Log UFC/gill) was significantly higher (p ≤ 0.05) than that of CHB (5.53 Log UFC/gill). In fish caught during August, the load of potentially histamine-producing bacteria in the gills was significantly higher (7.64 Log UFC/gill), than in the months of May (5.71 Log UFC/gill), June (5.67 Log UFC/gill) and July (5.79 Log UFC/gill)