• All schemes have a yearly schedule
• Every set of samples (round) for a single scheme is referred to as a ‘Distribution’
• Normally two to six distributions per year – depending on the scheme
• Every distribution has a unique distribution number
• Every distribution contains two or three samples each with a unique sample number
• Participants must receive all the samples from a distribution, but not all the distributions
• All schemes are accredited
• Samples are stable and homogeneous
• All samples are designed, prepared and tested by in UKHSA microbiologists
• Quality control tests reflect commonly used methods
• Samples that challenge particular examinations e.g. isolation, identification, enumeration and molecular examination
• Micro-flora representative of real food and water samples
• Significantly high proportion of positive samples
• Realistic levels of target organisms with background flora where appropriate
• Large numbers of participants (between 50 – 350 in most scheme) for robust data analyses
• Efficient global sample delivery service – over 70 countries
• Clear instructions and request forms
• Individualised reports normally published within three weeks of a distribution closing