ÎOl 



ments on the growth of moulds in liquids^ considering the 

 amount of water in the butter. 



To test the durabiUty of _^a sample of vegetable margarine 

 two methods may be followed. In the first it may be kept 

 at 20 C. (after having been inoculated with a mould causing 

 rancidity e. g. Cladosporium butyri), and then examined 

 occasionally. One may also melt the margarine carefully, gather 

 the water and inoculate this after sterilisation with Cladosporium 

 butyri. The latter method is less reliable and in the examination 

 only the former was applied. By the addition of certain quant- 

 ities of preservatives to the vegetable margarine, this latter 

 being inoculated with Cladosporium, the right quantity of pre- 

 servatives was found in order to keep the butter fresh for five 

 weeks at the least. 



It appeared from this that preservation with salt alone 

 requires 2,5-3 0/0, according to the percentage of water in the 

 butter. Therefore preservation is possible with salt alone, but 

 it has this great drawback that the flavour of the butter suffers 

 very much; 2 0/0 of salt might be considered as maximum to 

 an average 14 0/0 of water. When this quantity of salt or less 

 is used the addition of preservatives as benzoic acid, sodium 

 benzoate, boric acid or borax is inevitable, if the vegetable 

 margarine is to satisfy the public. 



The research brought to light that a percentage of 2 0/0 salt 

 preserves vegetable margarine satisfactorily, when 0.075 ^U ^^ 

 benzoic acid or 0.2 % sodium benzoate or a mixture of 0.05 % 

 benzoic acid and 0.05 0/0 sodium benzoate is added. Sodium 

 benzoate is easily soluble in water; when added as a solution 

 it is the most efficient. 



Vegetable margarine may also be kept fresh with the addition 

 of borax and boric acid, seeing that borax is easily soluble in 

 saltsolutions when boric acid is mixed at the same time. It is 

 clear that the solubility in water of preservatives is of import- 

 ance, as this indicates the rapidity with which these preser- 

 vatives get into the water contained in the margarine, during 

 the mixing process. Therefore the easily soluble sodium benzoate 

 is to be preferred to benzoic acid though the latter is a much 

 stronger preservative. Borax is only soluble in saltsolutions to 

 a small extent, but it easily dissolves when to 2 parts of borax 



