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Some Experiments With a Boric-Acid Canning Powder
Title
Some Experiments With a Boric-Acid Canning Powder
Subject
food safety
Excerpt
Among the many inquiries concerning canning problems received by the microbiological laboratory of the Bureau of Chemistry, in- formation as to the use of "canning powder" to supplement heat in processing has been frequently sought. These requests come from places widely enough separated to indicate that propaganda for the introduction of some sort of antiseptic in the home preservation of food is fairly widespread.
Specific inquiries supplemented by samples obtained for analysis indicated the use of a particular preparation in many sections of the country. Several series of packages of this preparation, therefore, were secured for study. Each package consisted of an envelope of white powder bearing printed directions for use. To furnish a basis for intelligent work one series of packages was analyzed. 1 The powder consisted of approximately 95 per cent of boric acid and 5 per cent of common salt, the actual divergences from this average being about one-half per cent in either direction. The net weight of 36 envelopes averaged 28.97 grams, with a minimum of 25.22 and a maximum of 34.89 grams. Evidently each package was intended to contain 1 ounce (28.34 grams) of powder. At the minimum content found, however, the loss of antiseptic power might be great, while at the maximum content the excess of toxicity might be serious.
The directions given on the envelopes of powder called for the use of one-fourth package (one-fourth ounce) to each quart of finished material, and provided a means for the rough division of the powder into fourths. No suggestion that the use of an excess of the canning powder might be harmful was offered. Considering the difficulty of estimating how much bulky fresh material would make a quart of finished or canned material, together with the haphazard method of measuring the powder and the wide range of variation found in the contents of the packages, the quantity of the canning powder actually used in successive lots of food would be variable enough to lower its antiseptic value, or, possibly, if in excess, to affect the consumer.
Specific inquiries supplemented by samples obtained for analysis indicated the use of a particular preparation in many sections of the country. Several series of packages of this preparation, therefore, were secured for study. Each package consisted of an envelope of white powder bearing printed directions for use. To furnish a basis for intelligent work one series of packages was analyzed. 1 The powder consisted of approximately 95 per cent of boric acid and 5 per cent of common salt, the actual divergences from this average being about one-half per cent in either direction. The net weight of 36 envelopes averaged 28.97 grams, with a minimum of 25.22 and a maximum of 34.89 grams. Evidently each package was intended to contain 1 ounce (28.34 grams) of powder. At the minimum content found, however, the loss of antiseptic power might be great, while at the maximum content the excess of toxicity might be serious.
The directions given on the envelopes of powder called for the use of one-fourth package (one-fourth ounce) to each quart of finished material, and provided a means for the rough division of the powder into fourths. No suggestion that the use of an excess of the canning powder might be harmful was offered. Considering the difficulty of estimating how much bulky fresh material would make a quart of finished or canned material, together with the haphazard method of measuring the powder and the wide range of variation found in the contents of the packages, the quantity of the canning powder actually used in successive lots of food would be variable enough to lower its antiseptic value, or, possibly, if in excess, to affect the consumer.
Creator
Edmondson, Ruth Bathurst
Thom, Charles
Giltner, Leigh T.
Date
1922
Relation
U.S. Department of Agriculture. Department Circular Number 237