Preservatives for Cream. 
405 
growth of bacteria ; but the character of the cream is altered 
differently according to the method employed. 
Sterilising — which, however, can only partially be accomplished 
— is done by raising the temperature to 150° or 160° F., and then 
reducing it below 40° F., thus killing the lactic acid organism. 
This is a suitable method for factories or for large producers and 
dealers in cream. The more common practice, however, is the use 
of preservatives. 
Hence the question arises, To what extent is the use of preserva- 
tives desirable or permissible ? 
Many different preservatives are in use, but most of them have 
a common foundation — boracic acid, or a mixture of borax and 
boracic acid. Although one may very rightly object to anything of the 
nature of a drug in food, it has not been shown that boracic acid when 
used in the quantity necessary to keep cream sweet for a reasonable 
time has any harmful effect. Salicylic acid was formerly used, and, 
from answers which have been given to questions asked in the agricul- 
tural newspapers lately, it would appear that it is still recommended. 
Moreover, in the Imperial Dictionary, under Salicylic Acid, it is 
stated : “It has come into very general use as an antiseptic sub- 
stance, and, being devoid of poisonous properties, it may be used for 
preserving foods, &c., from decay.” Nevertheless, it cannot be too 
widely known that its use is distinctly dangerous, that it has been 
condemned by medical authorities and its sale not allowed under the 
Food and Drugs Act, and that it should on no account be used in 
connection with food. 
Boracic acid, or a mixture of borax and boracic acid, is, there- 
fore, the safer substance to use ; but great caution must be exercised, 
especially in dealing with milk, on account of the greater quantity 
that is consumed. It may, indeed, be well supposed that, in the 
case of infants, whose diet is so largely composed of milk, the con- 
sumption by them of milk to which preservatives have been added 
may be harmful. 
The amount of preservative necessary for keeping cream or milk 
for a short time is very small. The following recipe is that of a mix- 
ture which will keep cream quite sweet for four or five days, even in 
hot weather : — 1 oz. of boracic acid, or J oz. of borax and | oz. of 
boracic acid, dissolved in a quart of hot water. This will suffice 
for 20 gallons of milk, or a tablespoonful of the solution to a quart 
(1 to 3,200 parts). 
Much stronger solutions are in constant use, as large a quantity 
as 1 oz. of boracic acid being sometimes put to two gallons. But 
when strong solutions are used, some other substance must be added ; 
for water will hold but a small quantity of borax and boracic acid in 
solution, and only a limited quantity can be put in without weakening 
the cream, besides which the acid would give the latter a bitter 
taste. 
Hence, glycerine and gelatine are sometimes used as preservative 
mixtures. Both will hold a large amount of borax and boracic acid 
in solution, and take away, to a certain extent, the bitter taste, 
