Services related to water pollution

Tender description

Public Health England (PHE) is planning to award a contract for the Automated Diluters to Don Whitley Scientific Ltd. The requirement is for the Food, Water and Environmental Microbiology Services (FWEMS), which are spread across 3 laboratory sites: Porton at PHE Porton Down, York at the National Agri-Food Innovation Campus (NAFIC), and London at PHE Colindale. The Food, Water and Environmental Microbiology Services (FWEMS) laboratories rely on now obsolete Biomerieux Dilumats, which are automated dilution systems. Each laboratory operates a number of units across their operations. ISO/CEN standard methodologies and EU Regulation require 25 grams of a food product be used for microbiological testing. This sub-sample is diluted 1:10 to allow homogenisation of the sample and enable enrichment testing for pathogens and direct testing on agar plates for specific bacterial species. Approximately 3 000 food samples are tested per month by the PHE Food, Water and Environmental Microbiology Services. The automated system removes risk of weighing and dispenser error if this was a manual method and it removes the risk of cross contamination and of injury from manual handling of large volumes of bottled media. This supports the requirement for the laboratories to be accredited by UKAS to ISO 17025, which is reliant on the accuracy of testing being controlled. The replacement automated diluter must: — be able to be calibrated by UKAS accredited calibration laboratory if this is not included as part of the service provision, — comprise a balance, sample bag holder and at least 1 liquid dispensing pump that allow automatic addition of diluent to a sample of known volume at different ratios, usually 1:10, — have an integrated autotare function, — liquid must be dispensed within 20 seconds for 225 ml for a 25 gram 1:10 dilution, — be accurate to weigh samples to 2 decimal places i.e. 0,00 grams, — be accurate in its measuring of weight and volumes of liquid. This should be confirmed by regular in-house checks, — the external dimensions cannot exceed 350 mm width x 350 mm depth x 500 mm high, — have a capacity of up to 7 kg for sample and diluent weight combined, — have a simple user keyboard and display or touch screen to aid in set up and use but protected from risk of coming in contact with liquids and causing contamination, — be able to be readily cleaned in the event of spillages, — have a movable dispensing arm to allow it to move out of the way of the sample bag to prevent contamination during addition/removal of the sample bag and sample or appropriate alternative mechanism or procedure, — be able to operate as a stand-alone unit within a laboratory setting, — all sample information must be stored for at least 14 days and can entered to provide full traceability matched to the sample, — be capable of transferring the sample information for external processing and storage.