Scombrotoxin fish poisoning remains the primary cause of seafood poisoning outbreaks despite preventive guidelines. The purpose of this study was to investigate the use of pH for the control of growth and histamine formation by histamine-producing bacteria in fish muscle. We examined pH effects on growth and histamine formation in tuna fish infusion broth and in inoculated tuna and mahi-mahi fish muscle. Histamine production was significantly less for all bacterial strains at pH 8.5 compared to pH 5.5 in tuna fish infusion broth with no significant difference in growth. Elevated pH due to phosphate treatment of fish muscle tissues significantly reduced histamine formation with no effect on the growth of histamine-producing bacteria. This study revealed that phosphate treatment of mahi-mahi and tuna fish muscle resulted in significantly lower histamine production over 4 d of storage at 10 °C. Phosphate treatment of fish muscle may serve as a secondary barrier in addition to FDA recommended time and temperature controls for reducing public health concerns of scombrotoxin fish poisoning.
Keywords: bacteria; barrier; fish; histamine; histidine decarboxylase; pH.
© 2015 Institute of Food Technologists®