Division II Digestion procedure

This procedure may involve complete pools (100 g of samples at a time) or pools of less than 100 g.

1. (a)

   Complete pools (100 samples at a time):

   1. (i)

      The Stomacher lab-blender 3 500 is fitted with a double plastic bag and the temperature control set at 40 to 41 °C.

   2. (ii)

      One and a half litres of water preheated to 40 to 41 °C is poured into the inner plastic bag.

   3. (iii)

      25 ml of 17,5 % hydrochloric acid is added to the water in the Stomacher.

   4. (iv)

      100 samples weighing approximately 1 g each (at 25 to 30 °C) taken from each individual sample in accordance with point 2 are added.

   5. (v)

      Lastly, 6 g pepsin or 18 ml liquid pepsin is added. This order must be followed strictly to avoid decomposition of the pepsin.

   6. (vi)

      The Stomacher is then allowed to pound the content of the bag for 25 minutes.

   7. (vii)

      The plastic bag is removed from the Stomacher and the digestion fluid is filtered through the sieve into a 3 litre beaker.

   8. (viii)

      The plastic bag is washed with approximately 100 ml of water, which is then used to rinse the sieve and lastly added to the filtrate in the beaker.

   9. (ix)

      Up to 15 individual samples can be added to a total pool of 100 samples and examined together with these samples.

2. (b)

   Smaller pools (less than 100 samples):

   1. (i)

      The Stomacher lab-blender 3 500 is fitted with a double plastic bag and the temperature control set at 40 to 41 °C.

   2. (ii)

      A digestion fluid is prepared by mixing about one and a half litres of water and 25 ml of 17,5 % hydrochloric acid. 6 g of pepsin is added and the whole mixed at a temperature of 40 to 41 °C. This order must be followed strictly to avoid decomposition of the pepsin.

   3. (iii)

      Of the digestion fluid, a volume corresponding to 15 ml per gram of sample is measured (e.g. for 30 samples the volume required is 30 × 15 ml = 450 ml) and transferred to the inner of the two plastic bags, together with the meat samples weighing approximately 1 g (at 25 to 30 °C) taken from each individual sample in accordance with point 2.

   4. (iv)

      Water at a temperature of approximately 41 °C is poured into the outer bag to make up a total volume in the two bags of one and a half litres. The Stomacher is then allowed to pound the content of the bag for 25 minutes.

   5. (v)

      The plastic bag is removed from the Stomacher and the digestion fluid is filtered through the sieve into a 3 litre beaker.

   6. (vi)

      The plastic bag is washed with approximately 100 ml of water (at 25 to 30 °C), which is then used to rinse the sieve and lastly added to the filtrate in the beaker.