- Latest available (Revised)
- 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. It is expressed as the quantity of phenol in μg liberated by 1 ml of reconstituted milk, as determined by the procedure described below.
The phosphatase activity of dried milks is determined by the ability of the phosphatase to liberate the phenol from disodiumphenylphosphate. The quantity of phenol liberated under prescribed conditions is determined by a spectrophotometric measurement of the colour developed with Gibb's reagent.
Barium borate hydroxide buffer: pH 10,6 ± 0,1 at 20 o C.
Dissolve: 25,0 g of barium hydroxide (Ba(OH)2.8H2O) in water and dilute to 500 ml.
Dissolve: 11,0 g of boric acid (H3BO3) in water and dilute to 500 ml.
Warm the two solutions to 50 o C and mix.
Shake and cool the mixture to room temperature.
Adjust the pH to 10,6 ± 0,1 with the barium hydroxide solution and filter.
Store the solution in a tightly stoppered container.
Before use, dilute the buffer with an equal quantity of water.
Colour development buffer.
Dissolve: 6,0 g of sodium metaborate (NaBO2) (or 12,6 g of NaBO2.4H2O) and 20,0 g of sodium chloride (NaCl) in water and dilute to 1 000 ml with water.
Buffer substrate solution.
Precipitant.
Dissolve 3,0 g of zinc sulphate (ZnSO4.7H2O) and 0,6 g of copper (II) sulphate (CUSO4.5H2O) in water and make up to 100 ml with water.
Gibb's reagent.
Dissolve 0,040 g of 2,6-dibromoquinone 1,4 — chloroimide (O.C6H2Br2.NCl) in 10 ml of 96 % ethanol. Store the solution in a dark glass bottle kept in a refrigerator. Discard this reagent when it has become discoloured.
Dilute 10 ml of Solution B (4.2), colour development buffer, to 100 ml with water.
Dissolve 0,05 g of copper (II) sulphate (CUSO4.5H2O) in water and make to 100 ml with water.
Dissolve 0,2 ± 0,001 g of pure phenol in water and make up to 100 ml in a volumetric flask with water. This solution can be stored for several months in a refrigerator. Dilute 10 ml of this solution to 100 ml with water. This diluted solution contains 200 μg of phenol in 1 ml and can be used for preparing more dilute solutions.
Precautions:
Avoid direct exposure to sunlight.
All the glassware, stoppers and removal material should be perfectly clean. It is recommended that they be rinsed and boiled with water or that they be treated with steam.
Avoid using plastic materials (stoppers for example) as they may contain phenols.
Saliva contains phosphatase; contamination by traces of saliva must therefore be carefully avoided.
If this limit is exceeded, dilute a suitable volume of reconstituted milk according to 6.1.1 with a suitable volume of this milk carefully boiled as indicated in 6.2.2 to inactivate the phosphatase present.
Phosphatase activity = 2,4 x P
where P = the quantity of phenol in μg according to 8.1.1.
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 phenol 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.
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: