According to Yamaguchi, Ohba, and Nasu, these systems have been used on criteria such as bacteria cell sorting, on-chip staining as well as the simple identification of protozoa or bacterial cells in river water. The chip-based systems are highly advantageous since they can be automated, and have low reagent consumption. In addition to this, they are small, cost-effective fast, and extremely reproducible. The chips are used once and the system is implemented when closed, which reduces the risk of biohazard. The efficiency of the system has been tested on small amounts of pseudomonas cells, which cause spoilage in milk. The pseudomonas spp. can contaminate milk in various phases of the growth cycle, as it “grows actively during refrigerated storage and produces enzymes such as proteases and lipases that degrade milk compounds, which result in off-flavours and reduced shelf life†(Yamaguchi, Ohba and Nasu 632).
Materials and methods
In the investigation, Pseudomonas cells in their stationary phase were acquired by incubation at 30°C in a liquid medium, while starved cells were obtained by a process involving centrifugation and washing with sterile phosphate-buffered saline, before being stored in the dark for a month, at 4°C. The milk used was inoculated with the pseudomonas cells at various densities, after being heated at 140°C, before the samples were prepared for Fluorescence in situ hybridization (FISH) in the liquid phase (Yamaguchi, Ohba and Nasu 632).
