The Delvotest® products based on microbial inhibition are validated for use in raw cow milk. In principle, Delvotest® can be applied to test other dairy matrixes or animal species with the following attention points:

• Maximum residues limits (MRLs).

• IDF guidelines on sample preparation for other dairy matrices.

• Validation required with negative and positive controls of the same type of dairy matrix or same animal type.

MRLs according to legislation

Maximum Residue Limits are only established for the composition of raw milk per animal species, for the most commonly used lactating animals, such as cow, goat and sheep. When testing compliance with existing legislation ensure that the correct species MRLs are used.

The processing method of other dairy matrices can vary, resulting in different product concentrations. Therefore, it is not possible to have established maximum residue limits. However, processed milk and milk products must also be free from antibiotic residues. This assurance is typically achieved by testing the raw liquid milk before it undergoes processing. When processed milk products need to be tested, the user should follow specific instructions on sample preparation as described in the following point.

IDF bulletin for other dairy matrices

Processed milk products can vary in composition and have different physical properties than raw milk. Milk powders, creams and whey come with varying concentration, solids content or pH. For example, microbial inhibition tests based on a pH indicator, like Delvotest®, can be affected by the use of alkaline whey.

Use the FIL-IDF B471 guidance, when testing products from other dairy matrices to ensure proper sample preparation. The online document is public - read here: Bulletin 471/2014.

Validate the performance

Whether you test cow milk, other species or other dairy matrices samples, we recommend validating your Delvotest® results for each species and dairy matrix. Before testing any unknown samples, follow the instructions below to establish the correct reading time and verify the performance.

• Use negative samples, of the Dairy matrix in scope, to set the incubation time.

• Use positive samples, of the Dairy matrix in scope, to confirm the test sensitivity.

For goat and sheep milk the incubation time is slightly prolonged in comparison to cow's milk. Refer to our control time article for more information.

When testing other dairy matrices, the incubation time may be prolonged because of lacking the normal milk composition.

The user is responsible of the local validation made as described above.

SAQ:

• Can I test whey powder/cream/butter with Delvotest®?

• Can I test camel or buffalo milk with Delvotest®?

• Can I test other animal other than cow, goat and sheep with Delvotest®?

Attachments

pdf: Regulation EU.pdf

pdf: Validation other dairy matrix-EN-MASTER-20240424 AB-JK.pdf