Abstract

TORRES, Silvia; ROECKEL, Marlene  and  MARTI, M. Cristina. Histamine formation by Morganella morganii isolated from Trachurus murphyii (Chilean mackerel). Lat. Am. appl. res. [online]. 2002, vol.32, n.2, pp.205-208. ISSN 0327-0793.

Morganella morganii, the most histaminogenic bacteria in chilean mackerel, was isolated and used to study the effect of temperature on h istamine production in this fish. Growth and histamine production rates at different initial pH (4.0, 5.5, 6.0, 7.0) and temperatures (10, 15, 20, 30 °C) were studied in batch cultures of M. morganii in a synthetic medium (TSBH- 2% histidine). An Arrhenius- type relationship between growth rate and temperature was found; its activation energy was 88.49 kJ mol-1. Bacterial growth and histamine formation were negligible below pH 5.0. The Leudeking-Piret expression for product formation rate was used; the α parameter was not significantly different at 30, 20 and 15 °C and its average value was 0.1 [mg histamine (mg cell)-1]. Assuming an initial protein content of 188 g (kg fish)-1, a level of 500 mg histamine (kg fish)-1 would be produced after 43 h at 15 °C or after 24 h at 20 °C. The prediction of histamine level at different temperatures can be used as a strategy of catch management.

Keywords : Trachurus murphyii; Morganella morganii; histamine production.

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