Determination of vanillin and related flavor compounds in cocoa drink by capillary electrophoresis.

A simple, rapid, and reliable capillary electrophoresis (CE) method using a photodiode array detector determined four flavor components (vanillin, ethylvanillin, 2-methoxyphenol, and 2-ethoxyphenol) in cocoa drink. Simple and rapid sample preparation required only dilution. Separation used 50 mM phosphate buffer and 2 mM cetyltrimethylammonium hydroxide (CTAH) at pH 10 with 10% acetonitrile. Sorbic acid was the internal standard (I.S.). Vanillin and related compounds were determined in 7 min, with the limits of detection at 1.6 microg/ml with S/N > 3 and a quantitation range of 5-500 microg/ml. Recoveries were investigated in cocoa drink samples with four flavor components. Mean recoveries were 96.3-103.8%. Using this method, the four flavor components were determined from cocoa drink, in which vanillin and ethylvanillin were originally contained as a flavoring and into which Bacillus firmus was added.

Development of a routine laboratory direct detection system of staphylococcal enterotoxin genes.

A novel direct detection system has been developed for eight staphylococcal enterotoxin (SE)-encoding genes (sea, seb, sec, sed, see, seg, seh and sei) in milk. Specific detection by real-time PCR was successful for all SE-encoding genes in the reference strains. Furthermore, a novel DNA-preparation method with good reproducibility [coefficients of variation 0.31, 0.99 and 1.21 % at 10(6), 10(4) and 10(2) c.f.u. (ml milk sample)(-1), respectively] was developed to overcome PCR inhibition in the milk samples. The combination of this DNA-preparation method and real-time PCR resulted in high sensitivity [between 1.1 x 10(2) and 1.0 x 10(4) c.f.u. (ml milk sample)(-1)] and allowed the completion of the entire procedure within 4 h. Results of an evaluation of this method for the detection of SE-encoding genes using known outbreak milk samples produced results showing good correspondence with the reversed passive latex agglutination assay. In addition, this newly developed system can be applied to clinical samples such as faeces and vomit. Consequently, the system should be useful in the routine direct detection of SE-encoding genes in food-borne-poisoning samples.