Bleaching of Flour

By E.F. Ladd and R.E. Stallings

SummaryIn 1906 the U.S. Congress passed the landmark Pure Food and Drugs Act, the first federal law to directly address the safety of chemical additives in America’s foods. One such additive was the bleach nitrous oxide, a compound used by industrial millers to give wheat flour the ultra white color so prized by consumers at the turn of the twentieth century. In this frank report—published just months after passage of the “national pure food law”—researchers at the North Dakota Agricultural Experiment Station discuss the negative effects of exposing wheat flour to nitrous oxide, from the destruction of the nutritional value of the flour itself to the occurrence of noxious nitrous by-products in bread made from the flour. The authors also include the results of a survey of the people most intimately familiar with flour bleaching, America’s millers, whose responses reveal the true motive for the practice: to make lower grade flour look—and sell—like higher grade. Thanks to the powerful influence of the millers, the use of nitrous oxide to bleach flour continued after passage of the Pure Food and Drugs Act, and in spite of a Supreme Court ruling in 1914 condemning the practice as a violation of the pure food law, the U.S. Department of Agriculture never once has attempted to enforce the court’s decision. This article—one of the oldest in the SRP Historical Archives—is a truly historic document that sets a time and place for the onset of the commercial destruction of America’s food supply. From Bulletin No. 72, North Dakota Government Agricultural Experiment Station, 1906. Reprinted by the Lee Foundation for Nutritional Research, 1951. 

The following is a transcription of the original Archives document. To view or download the original document, click here.

Bleaching of Flour[spacer height=”20px”]

The question has been frequently asked of this department whether the bleaching of flour, as now practiced in some of the flour mills, would make the product in violation of the law in this state or of the national pure food law [the Pure Food and Drug Act of 1906].

The attention of this department was first called to the matter of flour bleaching in 1905, and there have been made investigations and observations since that date to determine just what attitude the department should assume with regard to this important question. Now that the national law will soon come into force, it is very important that some decision be made in order that millers as well as dealers may know whether their products are in violation of the food law.

As showing the attitude and opinion of other investigators, it may be said that Professor Fleurent, in an address before the International Congress of Millers in Paris, stated that flour bleaching is primarily due to the absorption of nitrous products by the fatty matters; that the gases that are efficient agents in bleaching flour are identical whether produced by electrical or chemical processes; and that ozone is a useless bleaching agent and positively harmful.

In his experiments he showed that [when flour was bleached] the character of the fats was changed, as indicated by their iodine absorption; that the acidity of the flour was increased; that there were from 20 to 50 milligrams of the nitrogenous matter absorbed by the flour to 1000 grams [of flour]; and that in the bread produced from such flour there was found from 15 to 38 milligrams [of nitrogenous matter]. He then raised the question as to whether the presence of nitrous acid or of nitrites would be considered harmful or physiologically active as consumed in the bread and various other food products containing flour.

Brehm, as the result of a critical study of the Alsop method of bleaching flour, states that the method depends on the formation of nitrogen dioxide, which is allowed to act on the flour, and that the odor and baking quality of the flour were unfavorably affected and its acid contents increased. According to this author, the color was not improved by bleaching, and he concluded [also] that ozone cannot be used as a bleaching agent since it imparts an odor to the flour that renders it unfit for use.

Snyder concludes, as a result of experiments before the method had been commercially adopted in this country, “that color is an important characteristic in determining the commercial value of flour, and because of this, processes have been devised for bleaching and improving the color of inferior flours” (Bulletin 85, University of Minnesota Agricultural Experiment Station). He says that bleaching did not improve the bread-making qualities of the flour—the loaves from the bleached flours being smaller and lighter in weight. And he concludes that there appears to be no gain in bleaching purified flours made from a good quality of wheat.

Dr. Fischer of Wisconsin, in personal correspondence, says, “Several years before I became connected with the Wisconsin Dairy and Food Commission, I did a little work on the bleaching of flour with nitric acid for a friend of mine who was in the milling business, and at that time I concluded that the practice was a fraudulent one—and so informed my friend.”

It will thus be observed, and it is generally maintained, that the process of bleaching is a questionable practice.

Tasker, in an address before the London Flour Trade Association, said, “The process of bleaching should be carefully avoided or it will do the trade great harm.” And he then quotes the opinion of an English baker, who said, “Bleaching is no good to any one except the miller who wants to deceive his buyers and then hunt around for fresh ones.” To which Tasker adds, “That is the general opinion, though it may not be put so straight very often.”

One clause in the rules and regulations for the enforcement of the national food and drug act reads, “The term ‘stain’ includes any change produced by the addition of any substance to the exterior portions of foods that in any way alters their natural tint.” It is therefore difficult to see how flour should escape being brought under the term of this clause when the same has been bleached.

Again, the clause—with regard to the application of preservatives—would seem to provide that if there remains a harmful residuum in the prepared product, the sale of the food would be illegal.

Fleurent concludes that bleaching acts as a preservative for the flour. If this be true and there is present an appreciable quantity of nitrous oxide, nitrous acid, or the salts of nitrous acid, then the flour becomes illegal.

The National Standard Dispensary says with regard to the action of nitrites, under “amyl nitrite,” that they produce cyanosis, throbbing in the head, vertigo, staggering, roaring in the ears, hurried and deep or occasional respiration, increase in the force and rapidity of the heart, decrease in blood pressure and temperature, and finally complete relaxation. Medicinal amounts depress the motor centers of the spinal chord, and overdoses depress the motor nerves and sensory centers of the chord and muscles. The dose of amyl nitrite is from three to five drops. The medicinal dose of sodium nitrite is from one to two grains; it acts similar to amyl nitrite but somewhat more slowly.

It becomes therefore important to determine the effect on flour of the bleaching and whether nitrous oxide or nitrites are present in the bleached flour—and, further, whether these products remain as a constituent of the bread when the same is ready for consumption. It is also important to determine whether the process of bleaching has in any way injured the quality of the flour and whether the process as practiced permits of fraud in the handling and sale of flour.

After having made some preliminary investigations with flours as found on the market and with samples of known quality from the mills—before and after bleaching—it seemed desirable to conduct an investigation under the personal supervision of a member of our staff. Therefore [chemist] Mr. R.E. Stallings was authorized to make certain investigations, the results of which are presented herewith.

[Letter:][spacer height=”20px”]

November 12, 1906
Prof. E.F. Ladd

Dear Sir:

In accordance with your instructions, I visited Valley City on October 13th and investigated the bleaching of flour both by the Williams and the Alsop processes. I secured samples of their patent [highest grade] flour—both unbleached and bleached for sale—and, at my request, two samples that were overbleached—one for 5 minutes and the other for 15 minutes. I also secured samples of their “clear,” or second grade, under the same conditions as the patent. The methods of bleaching by both processes are essentially the same—by passing an electric current through the air and forcing this air into agitators where the flour is exposed to this air for about 1 minute. The samples were brought to this laboratory, where they were carefully tested to note the influence of bleaching. Enclosed will be found a formal report of these tests, together with tests of other flours known to have been bleached.

Very respectfully,
(Signed) R.E. Stallings, Asst. Chemist

Tests for Nitrous Acid

In all the bleached samples, the presence of nitrous acid was found, [while] the absence of nitrous acid [was observed] in the unbleached. It was found in large quantities in the overbleached. A quantitative estimation was ascertained in several cases, as follows:

Sample No. 1:

Patent bleached for trade, in 5 grams: 0.0034 mg of N
This calculated as sodium nitrite (5 grams): 0.01671 mg
Calculated in flour for making 1 loaf (373 grams): 1.24656 mg NaNO2

Sample No. 2:

Patent overbleached for trade, in 5 grams: 0.0300 mg of N
Calculated as sodium nitrite in 5 grams: 0.014785 mg
Calculated in flour for making 1 loaf (373 grams): 11.0296 mg NaNO2

Sample No. 3:

“Clear” bleached for trade, in 3 1/2 grams: 0.0046 mg of N
Calculated as sodium nitrite in 3 1/2 grams: 0.02267 mg
Calculated in flour for making 1 loaf (373 grams): 2.4159 mg NaNO2

The above samples are from Valley City.

The following samples were taken from the Moorhead Mill (Williams process):

Sample No. 4:

Patent bleached for trade, in 3 1/2 grams: 0.0025 mg of N
Calculated as sodium nitrite in 3 1/2 grams: 0.01232 mg
Calculated as NaNO2 in 1 loaf (373 grams): 1.313146 mg

The question arose as to whether the nitrous acid or nitrites remained in the bread. After baking, the bread was cut in small pieces [and] treated with water in the case of the patents shown above, and nitrous acid reaction was plainly gotten. An attempt was made to determine quantitatively the amount, but I do not believe the results obtained are accurate—falling short of the [true] amount contained in the bread—since it would be difficult to extract the total amount of acid by treatment with water because the water would not easily penetrate every portion and dissolve the nitrous acid out readily. Following are the results obtained, however:

Patent bleached for trade—same as No. 1:

N: 0.0025 mg in 1/2 oz. of bread
NaNO2: 0.01232 mg in 1/2 oz. of bread
1 loaf of 18 oz.: 0.44352 mg of NaNO2

Patent overbleached—same as No. 2:

N: 0.0200 mg in 1/2 oz. of bread
NaNO2: 0.0985 mg in 1/2 oz. of bread
1 loaf of 18 oz.: 3.546 mg of NaNO2

The method of the determination of nitrites was as follows:

A given amount of flour or bread, as the case may be, was weighed and placed in a flask, and a given amount of pure distilled water was added. The flask was then corked and agitated at short intervals for 30 minutes; the solution was then filtered, and an aliquot portion taken and treated as follows. One drop of concentrated hydrochloric acid was added, and 1 cc of the sulfanilic acid solution was added. This was followed by 1 cc of a solution of hydrochloride of naphthylamine. This mixture was shaken, covered with a watch glass, set aside, and allowed to stand for 30 minutes. At the same time, a known amount of the standard solution of sodium nitrite was treated in the same manner. At the end of 30 minutes, these solutions were compared with the standard in the colorimeter.

Baking Tests

Two bakings were made to see whether there was any difference in the size of loaves made from bleached and unbleached flours. The amount of flour was carefully weighed in each case, and the same amount of sponge was added. The results are as follows:

Baking (October 23rd) Amount of Flour Size of Loaf
Unbleached (Honey Brothers) patent 373 grams 23 1/4 x 18 1/4 in.
Bleached (Honey Brothers) patent 373 grams 23 1/8 x 18 1/8 in.
Unbleached (Valley City) patent 373 grams 25 x 20 in.
Usual-bleached (Valley City) patent 377 grams 24 1/2 x 19 3/4 in.
Overbleached (5 min, Valley City) patent 380 grams 24 7/8 x 20 1/2 in.
Overbleached (15 min, Valley City) patent 379 grams 24 3/8 x 19 1/2 in.


Baking (October 23rd) Amount of Flour Size of Loaf
Unbleached (Valley City) “clear” 373 grams 25 1/4 x 20 1/2 in.
Bleached (Valley City) “clear” 373 grams 25 x 20 in.
Overbleached (Valley City) “clear” (5 min) 379 grams 25 1/8 x 20 in.
Overbleached (Valley City) “clear” (15 min) 378 grams 25 3/4 x 20 3/4 in.

In regard to the color, the bleached flours were whiter than the unbleached. The bread was slightly whiter. Several who tested the bread noted that there was a decided difference in the taste and odor of the breads from bleached and unbleached flours. Personally, I do not think they are improved in odor and taste by bleaching, and the majority of the people who tested them agree with me. The difference in odor can be noted in the flours. As one visitor to the laboratory remarked, the unbleached flours smelled like flour, while the treated samples had a pungent smell. In doughing, the bleached flours were much more sticky than the unbleached.

It will be noted that in the above baking a slightly larger amount of flour was used in some cases than in others. This is due to the fact that with the same sponge added, the bleached flours, having less absorptive power, were sticky, and it became necessary to add a small amount of flour so they could be easily handled. Some test bakers report that they can make larger loaves from bleached flour than unbleached. This can be easily manipulated since the amount of yeast added in all cases is large, and a large loaf can be obtained from any kind or grade of flour. Again, the temperature of the oven will make quite a difference. If the treatment is exactly the same as regards the amount of flour, time of pulling, and time of raising, and the same temperatures of baking [are used], then unbleached flours will make larger loaves.

Effect on the Gluten

The glutens were tested along with their expansion. The method used was as follows. One ounce of flour was weighed out, and 280 grains of water were added to the flour in a cup; these were then mixed thoroughly with a spatula, and all particles were collected into a ball of dough. The cup was covered and allowed to stand for 30 minutes. The starch was then washed out in a stream of lukewarm water. The glutens obtained in the case of the unbleached flour were creamy in color, while the [glutens of the] bleached were whiter. The glutens were then placed in the Foster tester and baked for 25 minutes in the oven at 200 degrees C. The weights were removed after the first ten minutes. The following shows the results of these tests:

Trial No. & Bleaching Process Flour Used Amount of Flour Used Amount of Expansion
No. 1 (Alsop) Patent overbleached 31 grams 2.8 inches
Patent unbleached 31 grams 3.6 inches
No. 2 (Williams) Patent bleached 31 grams 3.5 inches
Patent unbleached 31 grams 4.0 inches
No. 3 (Asop) Patent bleached for trade 31 grams 3.0 inches
Patent unbleached 31 grams 3.6 inches

A test on the absorption of water by flours proves beyond a doubt that unbleached flour will absorb more water than the bleached flour. On this absorption, one of the bread-making values of a flour depends. The following shows the result of the test:

Flour Used Bleaching Process Absorption of Water (percent)
Patent unbleached Alsop 69.5
Same patent bleached for market Alsop 64.0
Same patent overbleached Alsop 60.0
Patent unbleached Williams 68.0
Same patent bleached for market Williams 63.5
[Photo of test samples, with caption:] No. 1. Overbleached. No. 2. Same unbleached. No. 3. Unbleached. No. 4. Bleached for trade. No. 5. Bleached for trade. No. 6. Same unbleached.[spacer height=”20px”]


The only excuse offered by the millers for the use of bleaching processes is that it makes their flour whiter. Snyder says, “The bleaching of flours only tends to destroy the characteristic natural color, which is desirable as indicating character” (Bulletin 85, Minn. Ex. Sta.).

The processes for bleaching have been devised for bleaching and “improving” the color of inferior flours. The manufacturers of these processes openly claim that they (the millers) can increase the percentage amount of patent produced. From our tests it would seem that this could be done without the purchaser becoming any the wiser because the clear grade of flour was susceptible of being “improved” as well as the patents. The absorptive and expansive powers of the glutens are decreased, and the bread will make a smaller loaf after being bleached.

The presence of nitrous acid in the flour not only gives the bread a decided odor and taste, but it would seem that the amount present in the bread would be harmful physiologically. In the overbleached there is approximately about one sixth of a grain, calculated as sodium nitrite, in the flour used for 1 loaf of bread.

While the results obtained indicate that there is a loss of nitrous acid in the bread from that in the flour, I do not believe such to be the case. I do not think that there would be any loss whatsoever in the process of baking, and the amount present in the bread would be equal to the original amount in the flour. We have had occasion previously to examine flours on the market that were overbleached and gave reaction as strong as the one overbleached by myself.

The claim is made that nitrous acid will form in flour from the air. Our experiments do not indicate this to be the case. Two samples of flour were taken from the Fargo Mill, one a patent and the other a “straight.” They had been on hand in the mill for at least five months and possibly longer. In these no trace of nitrous acid was found.

A sample brought up by Oscar Dahlgren that he had had on hand for two months and claimed to be unbleached showed upon examination to contain a slight trace but not enough to even read in the colorimeter. There can be no doubt that unbleached flours lying along side of bleached flours or unbleached flours from a mill where bleaching is practiced will become contaminated, as it is a well known fact that flours have the power of readily absorbing any gas or foreign odor in which they are placed.

The preceding data by Mr. Stallings are merely confirmations of results that have been secured repeatedly from samples of flour and bread made therefrom in this laboratory for the past eight months. In the foregoing table, the sample marked as “overbleached” does not contain a larger amount of nitrites than has been found in some of the commercial samples of flour on the market in this state before the present agitation began on the question of bleaching. At the present time, the flour is not being bleached to the extent that it formerly was.

That the gluten of the flour is injured by the process of bleaching would seem to be clearly shown by the data presented and in the plate [table] showing the expansion of the baked gluten, as already given. The experiments have also clearly shown that flour kept in a mill where the process of bleaching is conducted may be expected as the result of absorption to give a reaction for nitrous acid. Samples of unbleached flour in our laboratory (contained in bags) gave no reaction for nitrous acid or nitrites, but when they were placed between two bags containing flour that had been bleached, they soon absorbed a determinable quantity of the nitrous acid. On the other hand, samples of flour have been examined that have been kept for the past eight months in our laboratory away from the fumes of nitrous acid, and they give no reaction at the present time for this product.

In further confirmation of the fact that nitrous acid is not generally absorbed by the flour under ordinary conditions, our examinations of a flour that had been kept for at least five months in a flour mill where there had been no bleaching showed clearly no reaction for nitrous acid or nitrites; neither does the bread produced in this laboratory from such flour give any reaction for these ingredients. Every sample of bread produced from bleached flours, however, has shown clearly a reaction for nitrous acid, and the product was present in all cases in determinable quantities. And while in most cases our results were not quite as high as those of Professor Fleurent, nevertheless the relation between the nitrous acid in the flour and that in the bread prepared from the same corresponds closely with his figures.

Opinions Regarding the Bleaching of Flour

It seemed desirable to gather from the several millers—as far as possible—information with regard to the claims set forth for the bleaching of flour. Also, [we sought] the expression of those who have looked into the matter or were using the processes of bleaching. Therefore a letter, together with the following accompanying questions, was submitted to a large number of millers throughout the northwest.

1. What are the advantages of bleaching flour?

2. Is there danger in overbleaching flour?

3. What are the effects of overbleaching?

4. Does bleaching affect the bread-producing capacity of flour?

5. What method, if any, do you employ for bleaching flour?

6. By bleaching is it possible to dispose of the lower grades for a better price?

7. Has it been your experience that bleached flours have given consumers as good satisfaction as the unbleached flour?

8. By bleaching can wheats be milled to better advantage and, if so, for what reason?

9. If bleaching is beneficial, how do you account for the opposition from European bakers and leading eastern bakers in this country?

10. Any further information or suggestions will be much appreciated.

In reply many answers were furnished, some of which were very evasive and others straightforward. In some instances manufacturers declined to furnish information, but brief statements taken from several of the reports will clearly set forth the several views of those not wholly favorable to the process.

No. I.  This party, who is using the electrical process, says: “The only advantage that can come from bleaching is a possible improvement in color and keeping quality. Bleaching, when first introduced, was hailed by many manufacturers with more enthusiasm than judgment, and an attempt [was] made to produce high patent flours out of straight goods, thus producing a bad mess at the very start. Those manufacturers who have bleached only the patents, however, have been more successful.”

No. II. “Personally, we do not feel friendly to the bleaching of flour, as we believe it to be very detrimental to the best that is in the grain and has been the means of putting lots of flour on the market of lower values than formerly. And it is a grave question with us as to whether our national government will not, under the pure food law, prohibit the process.”

No. III. “The bleaching of flour is no benefit except to change the color from a creamy white to a pure white…Bakers object to bleaching flour because they prefer to do their own blending and mixing, using spring wheat and winter wheat, bleaching and blending them.”

No. IV. “There is danger of overbleaching, which leaves the flour a gray color. We believe there is some benefit, especially where flour is intended to be used immediately after being milled.”

No. V. “Bleaching makes whiter flour and whiter bread, but overbleaching makes it muddy gray, and low grades cannot be bleached to satisfaction. Bleaching should only be used where there is a demand on the part of the housekeeper for an extremely white flour.”

No. VI. “Bleaching ages and dries out the flour instantly—what would require two or three weeks aging to do. There is danger of overbleaching, but it does not effect the bread producing capacity. Sentiment is divided as to the benefit of bleaching. Eastern bakers perhaps oppose bleaching because it enables millers to combine the Kansas and spring wheat flours and sell the same for Northwestern flours instead of the yellow Southwestern.”

No. VII. “Since we confine our entire milling to selected spring wheat, we are confident that we can produce a superior flour without bleaching, and the principal advantage from bleaching would be to permit the substitution of low grade by mixing it with high grade patents, which is only another form of adulteration.”

No. VIII. “The chief advantage in bleaching is to give a flour age, but there is great danger of overbleaching, which tends to kill the germ and seems to effect the bread-making qualities of the dough. When the process of bleaching was first introduced, manufacturers claimed that it was possible to bleach the lower grades and therefore bring them into the class of high-grade unbleached flours; many mills attempted to do this with disaster, creating much prejudice.”

No. IX. “We have no bleacher in our mill. We have not been able to make up our minds that bleaching is necessary or of any decided advantage.”

No. X. “It is very questionable whether there is any advantage gained by bleaching; certainly there is danger of injury from overbleaching. Bakers prefer to do their own mixing; therefore [we say] select flour in its natural state.”

No. XI. “Our customers will not accept bleached flour, and we do not believe it is beneficial.”

No. XII. “There is no advantage in bleaching. Overbleaching weakens the dough. It is possible to combine a small percent of the bleached low grades with the patent flour and thus secure a better price, but the baker does not get as many loaves of bread per barrel.”

No. XIII. “Bleaching came as the result of a demand for a dead-white in place of creamy-white flour and bread. Much fault has been found by buyers with bleached flours; bleaching makes it impossible for buyers to judge the quality of the flours by the recognized standards, and [they] are thus led to purchase inferior flour that is overbleached and will give an endless amount of trouble. The only advantage seems to be to the miller, who desires to give his trade an inferior product in the hopes of increasing his profits, but he is bound to lose in the long run.”

No. XIV. “Bleaching is done principally to deceive; it takes the strength from the flour. The loaf of bread [made from bleach flour] is smaller and sickly looking, especially when overbleached. The process is not beneficial, and while the majority of mills bleach, 99 in every 100 are sorry that bleaching was ever invented.”

No. XV. “There is no advantage in bleaching; it destroys somewhat the rising quality of the dough when [the flour is] overbleached.”

No. XVI. “No advantage in bleaching; it does away with the strength of the flour. The unbleached flour always gives the best satisfaction, and the process [of bleaching] is not beneficial.”

No. XVII. “At the very commencement of the new crop, bleaching enables the miller to remove the natural bloom and produce a uniform tint. Overbleaching commonly results in a dead-white flour and a great loss of flavor. We do not believe in bleaching, and bakers in the old country will not use bleached flours knowingly, though they are probably using much bleached flour, not being able to detect it. But bleached flours are not as good as the natural article.”

No. XVIII. “The principal advantage of bleaching seems to be in the aging of the flour. Overbleaching gives the flour a bluish tint and an unpleasant taste in the bread. It also enables the mixing of the better lower grades with the high grades. ‘But you cannot fool all the people all the time.’ Bakers prefer to do their own blending and bleaching.”

No. XIX. “The chief advantage is that [bleaching] enables the miller to sell the flour made from the cheaper and undesirable grades of wheat as flour made from higher priced grain. He often mixes five percent or ten percent or twenty-five percent, as may be safely done, of the low grade with the patents and sells it all as patent flour. Overbleached flour shows on the face of it that it has been treated with some villainous process that has destroyed its character. It is lacking in bloom and is a deception, wherein the miller has attempted to profit. It enables the miller to avoid skill, and the bread-producing quality of the flour is damaged in proportion [to the extent that] the miller cheats by this artificial means. The despised yellow berry can be milled and bleached and passed off as a product of the highest grade spring wheat.

“We do not consider bleaching to be beneficial in the true sense of the word, and since intelligent bakers and consumers do not like to be deceived, they are therefore opposed to this process. Aging produced in the flour by the quick process [bleaching] does not correspond to that produced by nature. The bleaching destroys the essential oil, and the consequent yellow of the flour is thereby destroyed [but so is] the flavor, and any expert would at once detect a bleached flour by the taste as compared with the unbleached.

“Bleaching is a reproach to the milling trade comparable to nothing that has obtained general acceptance, and it will defeat its own purpose. It is an abomination, a deceit, a serious commercial venture; this is the first process to which millers have yielded in this country, and in five years hence no intelligent miller will confess that he ever owned a bleaching machine.”

No. XX. “The merry miller with his devious bleaching machine maketh the age to grow his flour beyond its years, and the patient buyer he carrieth the bag.”

No. XXI. “I  have never had any hesitancy in saying that if a flour is bleached only sufficiently to remove the yellow or cream color—in other words, if it is not overbleached—that the quality of the flour is not injured in any way. The change from a creamy white to a dead white is not an improvement and is particularly undesirable in spring wheat flours (which have always commanded a premium), for they lose their distinctive appearance. Overbleaching is injurious and produces dough of less volume or absorption. Bleaching enables the miller to produce a slightly larger percentage of higher grades.”

Information given by one of the leading flour laboratories throws some light on this subject when they say, “We have found it is not necessary to bleach all flours; in fact soft winter wheat flours are not improved by bleaching, since they already have a very high color and if this color is intensified, it makes the product look sickly.” They further state that “certain varieties of Kansas and Oklahoma wheats have always sold at a more or less lower figure than other wheats for the reason that they make a flour of a dark yellow color.”

One would infer from this then that these wheats not recognized as the equal of Northwestern spring wheats can by the process of bleaching be made to resemble the Northwestern spring wheat flours and be sold as such, but it is questionable whether they pay the farmer anything additional.

In a circular gotten out by one of the promoters of electrical bleaching, [the authors] say, “The degree of bleaching is regulated by the amount of current flowing through the cell and is controlled by a rheostat, and when adjusted, any variation is impossible…Flour treated by this process, after a thorough analysis of the tints by the use of tintometers, was pronounced by flour inspectors to have the spring wheat tinge that is so desirable in flour. All varieties can be whitened—without the loss of the bloom.”

In personal correspondence with one of the firms producing the bleaching apparatus, they stated, “By bleaching, more of the berry can be utilized for patents.” Again: “When bleaching processes were first introduced, some millers, being enthused by the great improvement in the appearance of their flours, endeavored to substitute lower grades of flours for their established grades. This of course can be done to a certain degree; it was very much overdone by some millers, but it is readily detected by the baker, and of course there is nothing to do on the part of the miller but to make it good.”

General Conclusions

1. Has any one a right to treat a product such as flour, which forms the basis of our food products, by a chemical process unbeknownst to the consuming public?

2. Bleaching is not an improved milling process but is the introduction of chemical agents for the purpose of treating the flour that is analogous to the bleaching of fruit and other food products.

3. There is employed in this process of bleaching a chemical agent physiologically very active.

4. The bleaching agent is nitrous oxide.

5. Nitrous oxide remains in the flour after bleaching.

6. Nitrous oxide or the salts resulting therefrom remain in the bread produced from flour so bleached.

7. The quality of the gluten is injured by bleaching.

8. It is recognized that ozone is not a bleaching agent that can be used for flour bleaching.

9. Bleaching permits using low-grade flours in place of patents.

10. Low-grade flours produced from well cleaned wheat can be successfully bleached to resemble high grades or patents.

Any farmer, teacher, or student in the state may have this bulletin mailed to his address, free of charge, upon application. (See pages 233 and 235 and back cover.)

By E.F. Ladd and R.E. Stallings, North Dakota Agricultural College. Reprinted from Bulletin No. 72, Government Agricultural Experiment Station of North Dakota, November 1906, Fargo, North Dakota, U.S.A., by the Lee Foundation for Nutritional Research. 

[Addendum: Commentary by Lee Foundation for Nutritional Research, January 1951:]

Is Flour Harmed by Bleaching?

Yes, in two ways:

1. Valuable vitamins are destroyed by the bleach chemical. When cattle are fed grain without these vitamins, they show no harmful effects until they suddenly drop dead. (See Science, Vol. 104, No. 2701, page 312.) Note that heart disease is the leading cause of death in this country. Is it the bleached flour we eat? Heart disease is rare in China, where bleached flour is also rare.

2. Bleached flour is so poisonous to dogs that they get “running fits” from eating white bread, a common disease known to all veterinarians. Heretofore considered due to the wheat proteins, the disease has recently been proven to be due exclusively to bleach chemicals in the flour. (This was reported in Nature, June 1947, in the article “Agenized Flour.”)

Bleached white flour was declared unfit for human food by the Federal Western District Court of Missouri in 1910 and subsequently wound up in a maze of legal technicalities that was finally settled in 1919. Although the Supreme Court demanded a new trial due to a legal slip in the original proceedings, it clearly outlined the scope and intent of the Pure Food [and Drug] Law (Sup. Ct. Rpts. Oct. 1913, Book 58, Law Ed., pages 658–663)

The enforcement of this decree, according to Dr. Harvey W. Wiley (first chief of the U.S. Food and Drug Administration), was halted through the political influence of the flour millers, and no notice of violations has since been made by the inspectors of the U.S. Food and Drug Administration. (See Dr. Wiley’s book The History of a Crime Against the Pure Food Law at your public library; self-published, 1929, pages 383–389.)

“Thus the very law that the Supreme Court has said was enacted chiefly to protect the public health has been turned into a measure to threaten public health and to defraud the purchaser of flour” (Dr. Wiley, page 391).

All preceding text published as single publication, Reprint 1, by Lee Foundation for Nutritional Research, January 1951. 

Reprint No. 1
Reprinted by Lee Foundation for Nutritional Research
Milwaukee, Wisconsin 53201

Printed in USA

Note: Lee Foundation for Nutritional Research is a nonprofit, public-service institution, chartered to investigate and disseminate nutritional information. The attached publication is not literature or labeling for any product, nor shall it be employed as such by anyone. In accordance with the right of freedom of the press guaranteed to the Foundation by the First Amendment of the U.S. Constitution, the attached publication is issued and distributed for informational purposes.

Patrick Earvolino, CN

Patrick Earvolino is a Certified Nutritionist and Special Projects Editor for Selene River Press, Inc.

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