D A I R Y N O T E S

POISONOUS ACIDS IN CONDENSED MILK

The presence in condensed milk of organic and mineral acids, in ex- cess of the amount which normal fresh milk contains, is conducive to the formation of lumps.

Excessive amounts of acid in condensed milk may be the result of fermentations but usually are due to lack of good sugar, or the use of acid flux in ma~ug or sealing of the tin cans. The presence of lumps in milk usually indicates that the milk is either acid or gaseous. The acid curdles the casein in the milk, which is detrimental to the market value of the milk.

The most common channel through which condensed milk becomes contaminated is through the use of zinc chloride as a flux in the making and sealing of the cans. The zinc chloride precedes the solder in the sealing process and some of it is sure to sweat through the seams into the interior of the can, chemically uniting with the casein forming caseinate of zinc, which is highiy poisonous. The presence of zinc chloride is noted by a pink or brownish red color of the milk.

In order to avoid the appearance of lumps in condensed milk from this source, cans should be used that are sealed with the flux that is acid free. Dry powdered resin, or resin dissolved in alcohol is harmless in this respect, and is just as effective as the acid fluxes.

OR~ N. SMITH, Ames, Iowa.

REPORT ON" TWO OLD SAMPLES OF BUTTER

Two samples of tinned butter, at least twenty years old, had been kept in the office of the Dairy Commissioner, Ottawa, exposed summer and winter to room temperatures.

EYA.mination on September 16 showed that both tins were in good condition, hermetically sealed and tight. There was no evidence of "swells" or other damage.

No. 1. (Laboratory No. 711479). Labelled "Pierre de Bacourt, Dor- chester, Que. Extra Finest Canadian Butter." Packed dry in round tin. On opening the tin the butter was found to be soft, with no tex- ture. In appearance it was oleogenous and curdled. Color:light (pale)

174

DAIRY NOTES 175

yellow: Odor: slightly rancid, but largely yeas ty and not ve ry un- pleasant. Very disagreeable taste and quite non-edible.

No. 2. (Laboratory No. 7]d~80). Labelled "Pure Canadian But te r . " Canadian Government Dai ry Station, Calgary, Alta. Packed in brine in rectangular tin, in two 1-pound prints, each wrapped in parchment paper. No liquid on opening tin. Very strong rancid odor, slightly aromatic. Very soft, with curdled appearance and no texture. Color: pale yellow; white in spots or patches. Absolutely non-edible.

Analysis

W a t e r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . :. F a t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C u r d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ash'{" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NUMBER 1

14.87 79.75 1.42 3.98

99.98

3.80

NUMBER 2

33.60* 57.24

3 .03 6.11

100.00

5.94

* This includes water absorbed from brine in which the butter was packed. t Including salt.

Analysis of butter fats

Butyro-refraetometer at 25°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I o d i n e No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reickert Meisl No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Polenski No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acid No. Percentage of free acid in oleic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soluble fatty acids as butyric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Insoluble fatty acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Saponification No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NUMBER 1

48.98 30.70 31.10 2.03

45.33 22.45 5.25

84.93 227.6

NUMB~ 2

43.44 31.62 25.45 2.75

121.3 60.08 4.II

86.92 225.8

The refractometer readings are in each case lower than would be expected with normal butters. The lowering of the refractometer in- dices is explained by the abnormal content of flee f a t t y acids (Lewko- witsch, Yol. I, p. 338).

The iodine numbers are normal. The lower Reichert Meisl No. and higher Polenski No. for fa t No.

2 would seem to indicate conversion of soluble volatile acids into in-

176 DAmY NOTES

soluble volatile acids in the presence of a large amount of water. This deduction is further supported by the figures obtained for soluble and insoluble fatty acids.

The acid numbers are very high especially in No. 2, and indicate the effect on hydrolysis of glycerides produced by the presence of a large amount of water.

The saponification values are normal. For comparison the following limits for normal butter are given

(Lewkowitsch, Vol. I, p. 338).

Butyro-refractometer at 25°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49.5-54.0 Iodine No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26.0-3520 Reichert-Meisl No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.~)-29.4 Polenski No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Acid No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 Soluble fatty acids as butyric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.0 Insoluble fatty acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87.0 Saponification No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224.0

FRANK L. SHUTT, Dominion Chemist, Department of

Agriculture, Ottawa, Canada.

Dairy Bacteriology. PROFESSOR ORLA-JENSEN. Published by J. & A. Churchill, London.

Dr. Orla-Jensen, Professor of Technical Biochemistry in the Poly- technic College, Copenhagen, Denmark, has recently brought out a new addition of his Dairy Bacteriology which has been translated into English. This work is a fine addition to our text-books on Dairy Bac- teriology. I t ~ims to make practicaI application of bacteriological principles to dairy work. It is the outgrowth of the author's twenty- five years experience in bacteriological research.

Among the subjects covered are: Micro-organisms and Fermenta- tions, Bacteria, Yeasts and Moulds, Cleaning and the Procurement of Milk, Preservation of Milk, Application of Lactic Acid Fermentation in the Dairy Industry, Microflora of Butter, The Ripening Processes of the Different Cheeses, The Grading of Milk.

J. H. F.