Modelling growth and histamine formation of Klebsiella aerogenes TI24 isolated from Indonesian pindang

• Published in: International journal of food microbiology 2022-02, Vol.362, p.109459-109459, Article 109459
• Main Authors: Rachmawati, Novalia, Powell, Shane M., Triwibowo, Radestya, Nichols, David S., Ross, Tom, Tamplin, Mark L.
• Format: Article
• Language: English
• Subjects: Aerogenes; Animals; Coastal zone; Enterobacter aerogenes; Fish; Fish Products - analysis; Fishery products; Growth rate; Histamine; Histidine; Indonesia; Klebsiella; Klebsiella aerogenes; Lag time; Mackerel; NaCl; Population density; Prediction; Processing strategies; Social values; Sodium chloride; Temperature; Traditional foods; Tuna; Yield factor
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2021.109459

Indonesian salted-boiled fish (pindang) is a popular traditional food in Indonesia, which is made from Scombroid fish such as tuna and mackerel. As with other traditionally prepared fish products, pindang has important economic and social values, especially for those living in the coastal areas of Indonesia. However, pindang is a major cause of histamine fish poisoning (HFP) for consumers. Klebsiella aerogenes T124, a relatively high histamine-producing isolate from pindang, was used to describe lag time (λ), growth rate (μmax), maximum population density (Nmax), and histamine production in histidine broth and artificially contaminated Grey mackerel. Broth was adjusted to 1.5, 6, 10 and 20% w/v NaCl; mackerel was treated with 6% w/w NaCl, a level common to Indonesian industry practice, or not treated with additional NaCl. Samples were incubated at 10, 15, 20 and 30 °C. In broth, μmax and Nmax were significantly affected by temperature and NaCl, respectively, with λ influenced by both parameters. In control fish, μmax was significantly affected by temperature and NaCl, except at 10 and 15 °C; for 6% NaCl treatment, growth was only observed at 20 and 30 °C. Under similar incubation conditions for broth and fish, histamine formation was markedly affected by NaCl concentration. In broth, −5.1 to −6.6 log μg of histamine was produced per CFU, versus −4.6 to −6.6 log μg per CFU in fish. This study demonstrated that mackerel treated with 6% NaCl and stored at 10–15 °C prevents growth of K. aerogenes strain TI24 and formation of toxic levels of histamine. •μmax and Nmax were significantly affected by temperature and NaCl, respectively.•Histamine production was affected by NaCl, with higher levels of histamine in broth.•In broth, −5.1 to −6.6 log μg histamine/CFU observed versus −4.6 to −6.6 log μg/CFU in fish.•6% NaCl and at 10–15 °C prevented growth and toxic histamine levels in fish.