Histamine-forming bacteria (HFB) were isolated from the 70 salted fish samples bought from town markets of Guangdong Province of south China. In addition, the histamine-forming ability of HFB was analyzed. There were 31 strains of HFB isolated from 36 salted fish pickled overnight. They were identified as six bacteria species: Vibrio alginolyticus, Vibrio rumoiensis, Staphylococcus saprophyticus, Staphylococcus xylosus, Lactococcus lactis, and Morganella morganii. The rate of confirmation of V. alginolyticus was highest (23 of 31), exceeding 200 mg/kg histamine. In particular, M. morganii produced a histamine amount that exceeded 2,000 mg/kg, although it was only one isolate in this study. In addition, five bacteria species of HFB were isolated from 34 dried salted fish. Among them, S. saprophyticus was dominant in the dried salted fish but produced histamines below 200 mg/kg. However, Enterobacter aerogenes from dried salted fish formed a histamine amount exceeding 200 mg/kg. The study showed that the dominant strain of HFB was different in two kinds of salted fish. Both kinds of salted fish contained HFB whose histamine-forming capacity exceeded 200 mg/kg. As a result, the safety of salted fish should be of concern, especially salted fish pickled overnight.HIGHLIGHTSThe dominant HFB varies in two kinds of salted fish.The rate of confirmation of Vibrio alginolyticus was highest.Both kinds of salted fish contain high levels of histamine-forming bacteria.

The bacterial diversity of salted mackerel “one‐night courtyard” at soft frozen area (−7℃–0℃) storage was studied. The fish samples at 0, 14, 21, 28, and 35 days were analysis for bacterial structure using high‐throughput sequencing technologies (HTS) and biogenic amines using high‐performance liquid chromatography (HPLC). The analysis results of HTS showed that the dominant bacteria species was varied gradually following with storage time. On the 0th, 21st, and 28th days of storage, dominant Vibrionaceae was accounting for 71.70%, 59.16%, and 70.68% of the total sequences analyzed, respectively. On the 14th and 35th days, Shewanellaceae was the dominant bacterial, accounting for 87.53% and 70.95% of the total sequences analyzed, respectively. In addition, 21st and 28th days, an abundance of Operational Taxonomic Units (OTUs) was top. The dominant bacterial of Proteobacteria, Firmicutes, was producer of biogenic amines. Furthermore, the analysis results of HPLC shown the total biogenic amines of maximum amount 363.01 mg/kg in the sample of HY.14 lower than 1000 mg/kg of the FDA regulation. The range ability of cadaverine was obvious following with the storage time. Cadaverine was 87.36 mg/kg on the 0th day, and it was maximum amount of 276.89 mg/kg on the 14th days. Putrescine was 20 mg/kg on the 0th day and maximum amount of 55.04 mg/kg on the 28thdays of storage. The tyramine was smallest amount of production, and the largest amount was 38.99 mg/kg on 28th, and the smallest amount was 11.97 mg/kg on 35th. Nevertheless, the maximum amount of histamine was 55.04 mg/kg on the 0th day and about 23.14 mg/kg of histamine was little change from 14th to 35th days of storage. Dominant bacteria affect the change of biogenic amines. The study can help understand the interaction between microbial flora and biogenic amines in the salted mackerel of one‐night courtyard.