Retesting Failed Laboratory Samples


Suffolk Coastal Port Health Authority

Issue Number 01 | November 2013 |

Port Health Update - Imports of Food and Feed  

Retesting Failed Laboratory Samples

The law enforced by Port Health sometimes requires a sample to be taken and sent for laboratory analysis.  Samples may also be taken for monitoring purposes either as part of a program or in response to intelligence.  If the sample fails and the importer disputes the result; there is a process set out in the law that needs to be followed.

When samples are taken by Port Health for laboratory analysis, this sample is normally divided up into three parts. This is carried out either by Port Health or at the Laboratory.

  • Part 1 of the sample is the Port Health sample and will be analysed by the laboratory
  • Part 2 is for the importer and is referred to as the defence sample and can be made available for testing
  • Part 3 is referred to as the referee sample and is retained for independent analysis should there be a dispute
Importers own Analysis

If the importer wants to arrange to have the defence sample retested then arrangements need to be made to send the sample to a laboratory for testing. 

Selecting a Laboratory

The laboratory selected cannot be the same laboratory that Port Health used.  This would be considered to be a conflict of interest.  The laboratory must be accredited to carry out the required tests to the recognised ISO standard.  There is a list of approved official feed and food control laboratories available. (There are other accredited laboratories that may be used.)


The Importer is responsible for arranging the collection and submission of their defence sample to their selected laboratory, together with payment of associated costs.   Details of the chosen laboratory and a contact name will be required so that the sample can be dispatched.

Results of the Defence Sample

If the defence sample result agrees with the Port Health findings then this is binding, and the Port Health decision to refuse the consignment applies.  If the defence sample result does not match the Port Health result an independent analysis can be carried out.

Note:- It is sometimes possible to by-pass this stage and send the defence sample directly to the Laboratory of the Government Chemist (LGC) (see the following section) without the importer's own analysis being conducted.  This must be carried out with the consent of LGC and is usually in exceptional circumstances. If this is carried out then the sample costs from LGC may be significantly increased and SCPHA will not be responsible for 50% of the costs as in the standard procedure, i.e. the Importer will be responsible for all costs.

The Laboratory of the Government Chemist - Resolving Disputes through Referee Analysis

In the UK the Official Arbitrator is the Laboratory of the Government Chemist (LGC).  The Government Chemist will carry out further testing on the referee sample and will make a binding decision.  The analysis that is carried out is extensive and the process is very detailed so this analysis can be more time consuming than the official control laboratory analysis.

LGC will analyse the referee sample and provide the final result and decision for the consignment.  This decision must be adhered to by all parties.  Port Health will pay 50% of the final analysis cost where there is a dispute between the results of the Port Health sample and the defence sample.

If the Importer wants to use the LGC arbitration service it is the importer’s responsibility to contact LGC and make initial arrangements.  Further details of the procedure are available from the LGC.  Once the dispute has been raised LGC will then contact Port Health to get the sample details.  Port Health will then ask our laboratory to send the referee sample to the LGC.

When is retesting not possible?

In the case of microbiological samples/ contaminants, due to the highly perishable nature of the products concerned a sample for referee analysis may not be provided.  There are also issues with the distribution of micro-organisms within a food consignment as it is often not homogenous (even).

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