The Guideline 65 constitutes a collection of issues and solutions pertaining to liquid sampling – one comprehensive document reflecting the combined experience and expertise of four sampling valve manufacturers.

The impetus for the development of this Guideline came as several Valves Working Group members over decades had observed a continuous lack of awareness by many food producers regarding the importance of representative sampling.

A crucial challenge in liquid sampling is to withdraw a sample that is chemically and physically representative of the lot from which it is taken, while at the same time avoiding microbiological back-contamination of the production equipment and its contents.

Treating this issue the Guideline describes many different aspects, such as:

• The frequent use of valves which are not hygienic, because they are not cleanable
• The use of too small valves impeding the passage of lumps or particles, which makes the sample non-representative.
• The use of valves that cannot be sterilised when sterile conditions are required
• Single-port valves versus two-port valves
• The cleanability’s dependence on the valve’s internal geometry and surface condition

Many common gaps in knowledge about sampling manifest themselves in the following observed practices:

• Valves installed incorrectly (wrong orientation, difficult to access etc.)
• Valve not cleaned both before and after consecutive samplings of a given batch
• Use of flaming as a sterilisation method
• Failure to comply with maintenance intervals
• Insufficient SOPs (different operators perform sampling differently)
• The use of inappropriate sample containers

The objective of the Guideline is to provide a guide for choosing, operating and maintaining the right sampling equipment for the required purpose.