Histamine production by Raoultella ornithinolytica in mahi-mahi meat at various storage temperatures

Mahi-mahi meat was inoculated with Raoultella ornithinolytica at 5.0 log CFU/g and stored at -20 degrees C, 4 degrees C, 15 degrees C, 25 degrees C, or 37 degrees C to investigate bacterial growth and formation of total volatile base nitrogen and histamine in mahi-mahi meat. R. ornithinolytica grew rapidly in samples stored at temperature above 15 degrees C. The histamine contents quickly increased to higher than 50 mg/100 gin samples stored at 25 degrees C and 37 degrees C within 12 hours as well as those stored at 15 degrees C within 48 hours. The total volatile base nitrogen contents increased to higher than the index level (30 mg/100 g) for fish decomposition at 25 degrees C within 48 hours and 37 degrees C within 24 hours. However, bacterial growth and histamine formation were controlled by cold storage of the samples at 4 degrees C or below. Once the frozen mahi-mahi samples stored at -20 degrees C for 2 months were thawed and stored at 25 degrees C after 24 hours, histamine started to accumulate rapidly (>50 mg/100 g of fish). Copyright (C) 2014, Food and Drug Administration, Taiwan. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license.