Comparison of Four Agar Media for Detection of Histamine-Producing Bacteria in Tuna .

In a comparative study to determine their effectiveness for early detection of prolific histamine-producing bacteria from tuna samples, Niven's medium proved to be superior to three modifications of the medium. Presumptive colonies could be detected in 24 h on Niven's agar surface-plated and incubated at 35°C. Following confirmatory histamine determination with high performance liquid chromatography of the tuna fish infusion broth inoculated with presumptive histamine-producers and non-producers, detection rates of 95.8 and 93.9% were obtained from temperature-abused and bacteria-spiked tuna samples, respectively, using Niven's agar. The other three modifications provided much lower detection rates and higher false-positive and false-negative results than did Niven's agar.