Separation of viable histamine-producing bacteria from yellowtail meat components by density gradient centrifugation

Development of a density slicer for the simple collection of respective density layers after stepwise density gradient centrifugation

Density gradient centrifugation (DGC) is useful for the separation of living microbial cells from food samples that are not filterable. After DGC, however, careful operation is necessary to collect each density layer. For a simple and reproducible collection after DGC, we have developed a seamless operation system composed of a 5-needle unit, a microchannel plate, and a microflow controller, and named this a density slicer system. Two types of 5-needle units were devised and both showed nearly the same performance. Reproducible results with the automatic operation system could be demonstrated using an Escherichia coli cell suspension.