3 de janeiro de 2013

Corantes artificiais e DNA.

   Photo by Mohamed Babu.

   Food coloring and DNA mutations
   By: Jaqueline L.B. with cooperation of Doctor Bartlett M.

In the history of the world we have never had so many cases of cancer than now. The worse part of this statement is that the numbers are just increasing as we think about them. According the WHO 7.6 million people worldwide died from cancer in 2008 and 30% of cancers could be prevented. According to the National Cancer Institute, cancer is a term for division without control of abnormal cells. There are several causes of cancer, the one we will be talking about is the DNA mutations caused by chemicals
known mutagens. It is widely known that many of the products we use in our everyday life have very harmful chemical substances, that have the potential the change our DNA, sadly we do not think about it or we may live under the false believe that our government are here to protect us from harmful substances. Although history may be forgotten by some, one just need to look back some decades ago to uncover the sad
case of the very common used herbicide called Agent Orange, now known to cause several types of cancer, birth defects among many other diseases, according the United States health department. Additionally, no one needs to go as far in history to find hundreds if not thousands of products that are still damaging our DNA and having the potential of cause cancer among many other DNA related diseases in our everyday life.

To uncover these harmful potential mutagens the AMES TEST was developed by the scientist called Bruce Ames. The AMES TEST is a simple laboratory test that can be performed easily and relatively fast to predict the carcinogenic potential of any common substance. The assumption of the AMES TEST is that development depends on normal cell division and that if this equilibrium is disrupted by chemicals that are mutagen the DNA may be altered and mutations in the DNA sequence may lead to cancer. Additionally, because DNA is genetically universal in all arrays of life, the prediction of a chemical mutagen in a bacterium DNA is also indicative of the same results for human DNA. So with all this in mind, and to test it, the question now is, can a very widely used product in our everyday lives, artificial food color be a mutagen?


Food coloring is widely used in almost any processed food we can find in the supermarket now a days, especially among food sold to attract children. One may think that if food color is added in almost every food, and if the majority of these foods are to target children, it must be safe, or our government would not allow it to be sold. However, the hypothesis is that food coloring is not safe, and in fact may be a dangerous mutagen targeting our most young population.

The prediction is that food coloring is a mutagen and that the Ames test will show that bacterium DNA will mutate in the presence of food coloring. Using the Ames test for the experiment, the material was:
Three Petri plates, bacterium sensitive to streptomycin (about 0.1 ml per plate) , agar medium that contains streptomycin (10 um per ml), agar medium without streptomycin, filter paper disks, food coloring lake blue, and hydrogen peroxide.

For identification of each part of the plates was used the initials:

HP: Hydrogen Peroxide
FC: Food Coloring
E.C: Bacteria E-Coli
FD: Filter disk

All material is well sterilized and paper disks are soaked in each chemical to test for potential mutagens.

Plate 1 to test mutagenic potential and frequency: The plate was divided in 4 parts as shown:

This plate has antibiotic Streptomycin known to cause mutations in the bacterium E-coli, and is used as a control to check for mutagenicity. It is divided in 4 parts, one part with only e-coli, one with EC + FC, and one with EC + HP. We expect that all but EC+HP will mutate grow and divide.

Plate 2 to test for toxicity:

This plate does not have antibiotic and is used to check for toxicity of the substances in contact with E-coli. We believe that food coloring is not toxic to E-coli but hydrogen peroxide is, therefore, we expect the e-coli to die next to HP but to remain alive next to FC.

Plate 3 to test for contaminants:

This plate is used to test for contaminants. There is no antibiotic in this plate and nether there is E-coli. Therefore we expect nothing to happen to this plate because it should be sterile. However, if anything happens to it, the whole experiment may be contaminated and the results compromised.

All plates are left to incubate, and the results checked after 1 week is presented below.

Plate 1 (control for mutagenic potential and frequency) after 7 days of incubation.

Plate 1 the control for mutagenic potential and frequency: In this plate one can see that the bacteria E-coli multiplied in the incubation period in all but the part with HP chemical. The frequency of the mutation is also very large in the FC region.

Plate 2, control for toxicity after 7 days of incubation. 

In plate 2 the results shown that HP is very toxic to bacteria E-coly. However, FC is not toxic and EC grows well in it.

 Plate 3, control for contaminants, after 7 days of incubation.

In plate 3 one can see that there is the start of the formation of some type of contamination in our medium. The 2 yellow points that are showed in the photo should not be there if no contamination had occurred.


Although there were some limitations and problems with contamination of plate three, the results of the other 2 plates support the hypothesis that the widely substance known as food color blue lake is a mutagen and does cause the risk for DNA mutations that may lead to cancer. In plates 1 and 2 one can clearly see that FC is not toxic to bacteria but has indeed mutagenic proprieties as several other researches have
previously have shown, as for instance a research called Food Dyes a Rainbow of Risk from the Center for Science in the Public Interest. The experiment also reflect what other similar studies using the Ames test have previously discovered, that although food coloring has moderate mutagen proprieties the continuous use of it does increases the chance of mutations in human DNA which can cause cancer and several other related
genetic diseases and dysfunctions. Additionally, It would be advised for this test to be repeated to exclude any possibilities of results being altered by plates contamination, which in all cases do not exclude the possibility for food color being a moderate type of mutagen due to the extensive length of previous research’s already done on this subject.


Ames test:
Cancer mortality rates:
Agent Orange:
Food coloring and risks:
Evaluation of mutagenic potential of food dye:

2 comentários:

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