Page 161 - Analytical method for food addtives

106 Analytical methods for food additives

Repeatability
The absolute difference between two single test results found on identical test
material by one operator using the same apparatus within the shortest feasible time
interval will exceed the repeatability limit r in not more than 5 % of the cases.
The values are:
–
Nitrite corned beef (NO ) mean = 38.9 mg/kg r = 4.4 mg/kg
2
Reproducibility
The absolute difference between two single test results on identical test material
reported by two laboratories will exceed the reproducibility limit R in not more
than 5 % of the cases.
The values are:
Nitrite corned beef (NO ) mean = 38.9 mg/kg r = 10.3 mg/kg
–
2
(For further information on this method see DD ENV 12014-4:1998.)

9.6 Appendix 2: method procedure summaries (milk and
milk products – BS EN ISO 14673)

Method using cadmium reduction and spectrometry 2

Preparation of test sample: dried milk and dried whey
Transfer the test sample to a sample container of capacity about twice the volume
of the test sample. Close the container immediately. Mix the test sample thoroughly
by repeatedly shaking and inverting the container.

Preparation of test sample: caseins and caseinates
Thoroughly mix the test sample, if necessary after transferring all of it to a sample
container of suitable capacity, by repeatedly shaking and inverting the container.
Transfer 50 g of the test sample to the test sieve. If the 50 g portion directly passes,
or nearly completely passes the sieve, pass the whole mixed test sample through
the sieve. If the test sample does not pass completely through the sieve, use the
grinding device to achieve that condition. Immediately transfer all the sieved test
sample to the sample container and mix thoroughly in the closed container. During
these operations, take precautions to avoid any change in the water content of the
product.
After the test sample has been prepared, proceed with the determination as soon
as possible.
Preparation of test sample: cheese
Prior to analysis, remove the rind or mouldy surface layer of the test sample so as
to provide a test sample representative of the cheese as it is usually consumed.