- Latest available (Revised)
- Point in Time (13/11/1979)
- Original (As adopted by EU)
When the UK left the EU, legislation.gov.uk published EU legislation that had been published by the EU up to IP completion day (31 December 2020 11.00 p.m.). On legislation.gov.uk, these items of legislation are kept up-to-date with any amendments made by the UK since then.
Legislation.gov.uk publishes the UK version. EUR-Lex publishes the EU version. The EU Exit Web Archive holds a snapshot of EUR-Lex’s version from IP completion day (31 December 2020 11.00 p.m.).
EU Directives are published on this site to aid cross referencing from UK legislation. Since IP completion day (31 December 2020 11.00 p.m.) no amendments have been applied to this version.
This method describes the determination of phosphatase activity in:
dried high fat milk or high fat milk powder,
dried whole milk or whole milk powder,
dried partly skimmed milk or partly skimmed-milk powder,
dried skimmed milk or skimmed-milk powder.
The phosphatase activity of dried milks is a measure of the quantity of active alkaline phosphatase present in the product. It is expressed as the quantity of p-nitrophenol in micrograms liberated by 1 ml of the reconstituted sample, under the conditions described.
The reconstituted sample is diluted with a buffer substrate at pH 10,2 and incubated at a temperature of 37 oC for two hours. Any alkaline phosphatase present in the sample will, under these circumstances, liberate p-nitrophenol from added disodium p-nitrophenyl phosphate. The p-nitrophenol liberated is determined by direct comparison with standard colour glasses in a simple comparator using reflected light.
Dissolve 3,5 g of anhydrous sodium carbonate and 1,5 g of sodium bicarbonate in water and dilute to 1 000 ml in a volumetric flask with water.
Dissolve 1,5 g of disodium p-nitrophenylphosphate in sodium carbonate-bicarbonate buffer (4.1) and dilute to 1 000 ml in a volumetric flask with buffer (4.1).
This solution is stable if stored in a refrigerator (≤ 4 oC) for one month but a colour control test should be carried out on such stored solutions — see 6, precaution number 3.
Dissolve 30,0 g of zinc sulphate (ZnSO4) in water and dilute to 100 ml in a volumetric flask with water.
Dissolve 17,2 g of potassium hexacyanoferrate (II) trihydrate (K4Fe(CN)6.3H20) and dilute to 100 ml in a volumetric flask with water.
Precautions:
After use, test tubes must be emptied, rinsed in water, washed in hot water containing an al kaline detergent, followed by thorough rinsing in clean hot tap water. Finally, they must be rinsed in water and dried before use.
Pipettes must be thoroughly rinsed in clean cold tap water immediately after use, followed by rinsing in water and dried before use.
The test tube stoppers must be thoroughly rinsed in hot tap water immediately after use, followed by boiling for two minutes in water.
The buffer substrate solution (4.2) should remain stable for at least one month if stored in a refrigerator at 4 oC or less. Any instability is denoted by the formation of a yellow colour. Whilst the test is always read against a boiled product control containing the same buffer substrate solution, it is recommended that the solution should not be used if it gives a colour reading in excess of 10 μg when read in a 25 mm cell in the comparator using distilled water in the other 25 mm cell.
Use a separate pipette for each sample and avoid contaminating the pipette with saliva.
The test must not be exposed to direct sunlight at any time.
Dissolve 10 g of the powder in 90 ml of water. The temperature for dissolving the powder must not exceed 35 oC.
The direct reading obtained under 6.2.4 is recorded as μg p-nitrophenol per ml sample or per ml of reconstituted sample.
The difference between the results of two determinations carried out simultaneously or in rapid succession on the same sample, by the same analyst, under the same conditions, shall not exceed 2 μg of p-nitrophenol liberated by 1 ml of reconstituted milk.
The Whole Directive you have selected contains over 200 provisions and might take some time to download. You may also experience some issues with your browser, such as an alert box that a script is taking a long time to run.
Would you like to continue?
The Schedules you have selected contains over 200 provisions and might take some time to download. You may also experience some issues with your browser, such as an alert box that a script is taking a long time to run.
Would you like to continue?
Latest Available (revised):The latest available updated version of the legislation incorporating changes made by subsequent legislation and applied by our editorial team. Changes we have not yet applied to the text, can be found in the ‘Changes to Legislation’ area.
Original (As adopted by EU): The original version of the legislation as it stood when it was first adopted in the EU. No changes have been applied to the text.
Point in Time: This becomes available after navigating to view revised legislation as it stood at a certain point in time via Advanced Features > Show Timeline of Changes or via a point in time advanced search.
Geographical Extent: Indicates the geographical area that this provision applies to. For further information see ‘Frequently Asked Questions’.
Show Timeline of Changes: See how this legislation has or could change over time. Turning this feature on will show extra navigation options to go to these specific points in time. Return to the latest available version by using the controls above in the What Version box.
Access essential accompanying documents and information for this legislation item from this tab. Dependent on the legislation item being viewed this may include:
This timeline shows the different versions taken from EUR-Lex before exit day and during the implementation period as well as any subsequent versions created after the implementation period as a result of changes made by UK legislation.
The dates for the EU versions are taken from the document dates on EUR-Lex and may not always coincide with when the changes came into force for the document.
For any versions created after the implementation period as a result of changes made by UK legislation the date will coincide with the earliest date on which the change (e.g an insertion, a repeal or a substitution) that was applied came into force. For further information see our guide to revised legislation on Understanding Legislation.
Use this menu to access essential accompanying documents and information for this legislation item. Dependent on the legislation item being viewed this may include:
Click 'View More' or select 'More Resources' tab for additional information including: