Monday, 6 June 2011

Es ist Zeit für die Haushälterinnen, wir müssen die E.coli ausrotten

Microorganisms provide for us in many ways, from cheese to antibiotics there is a large number of applications that make use of their biotic properties. However, as it has been experienced in Germany and, apparently in some few other Northern European countries, their outburst is a matter of public safety and awareness has got to be relevant in what concerns dealing with these liabilities. Unfortunately people have died, lives are still threatened until cucumbers, soya bean sprouts and whatever comes to the equation are completely analysed for abnormal numbers. There is quite a handful of actions to be taken by the German and the EEC sanitary authorities. However, in the meanwhile and because alarm is the worst enemy of the public in these occasions, the best way to defend yourself and your family is to just attack the root of the problem.

In this sense, if the problem is Escherichia coli, learn how to deal with this life form. Regardless of your qualifications, your scientific knowledge and your ability to comprehend the ways of microbiology, if you have Bleach, you are a God damn good sniper on a E. coli hunting rampage. Do you want to learn how, so grab your natural scented bleach bottle and here we go:

Bleach is but sodium hypochlorite, an alcaline solution of around 10% active sodium chloride and 10 to 12 g/L sodium hydroxide. This solution does not occur naturally in the environment. Nonetheless it can be obtained by combining Chloride (gas) with an aqueous solution of Sodium hydroxide; or you just grab a quid and run to Aldi's. 

Bleach is soluble in water at room temperature, so it is important that you do NOT add bleach to boiling water (its boiling point can be found around 100º to 110ºC) because when exposed to a temperature of over 20ºC it will decompose. In addition, it is important to never mix bleach with acid solutions as the reaction is violent and releases chloride, forming toxic gases; but bleach is not known to be inflammable.

The reason why bleach kills different organisms is because the releasing of active chloride that will inhibit the enzymatic reactions within the cellular environment resulting in the denaturing of nucleic acids, and therefore, its consequent inactivation. The predominant decomposing reaction gives sodium chlorate (a) and the secondary decomposing reaction gives result to oxygen (b) (like when bleach is exposed to temperatures above 20ºC):

a) 3 NaClO                             2 NaCl + NaClO3 

b) 2 NaClO                            2 NaCl + O2

The gas (oxygen) produced is believed to be innocuous, and so is the salt of  sodium chloride. But bare in mind that bleach itself is dangerous and toxic for fish and marine species, thus it is important to discard it accordingly if in accountable volumes.

Doses to prepare for killing different microorganisms are presented below. The following information was passed to me in a doc file with no references, therefore I cannot assume that this info is entirely correct. I will search for official numbers that I personally do not know if are available in science articles for free-viewing, but as soon as I find them I will post them here right away:

- 0,15 a 0,25 ppm (0,000015%) eliminates vegetative bacteria in 30 seconds;

- 100 ppm ( 0,01 %) eliminates fungae in less than 1 hour;

- 200 ppm ( 0,02 %) eliminates 25 types of different viruses in less than 10 minutes;

- 100 ppm ( 0,01 % ) eliminates 107 S. aureus and P. aeruginosa in less than 10 minutes.

10ppm=1:5000; 50ppm=1:1000; 100ppm=1:500;

500ppm=1:100; 1000ppm=1:50; 5000ppm= 1:10 

If you don't like calculations just use the rule of thumb and add 3 drops of bleach for each litre of clean water, assuming that a teaspoon accounts for an average of 75 drops.

Remember to wash your fruit and veg in the water/bleach solution you've prepared allowing enough time for the microbicide action; and do not forget to wash them afterwards in running water to remove any traces of bleach and give them a shiny healthy tasty aspect.

I think it is quite an easy straightforward way of disinfecting the greens and the fruits in these awkward times. But if you have any intoxication problem, please read below for the actions you should take after calling your national emergency service:

1) If you've ingested bleach, wash your mouth with water and a wet towel. Drink water to dilute its concentration in the stomach and by any means avoid vomiting;

2) If the toxic effects were produced through contact with your skin, wash abundantly with water and soap for at least 20 minutes;

3) If the toxic effects are revealed due to contact with your eyes, wash immediately with plenty of water for at least 20 minutes keeping your eyes wide open to wash off the toxic solution;

4) Finally, if you've inhaled the toxic gases, something that will only happen if you mix it with other chemical product,  an acid for example, and I told you before not to do it so don't let me down... look for an open place with fresh air and as in any other emergency, ask for professional help;

In the making of this article I collected information from several sources, but mainly from:

CDC - Centers for Disease Control and Prevention,, last visited on the 06th of June 2011, last update on the 06th of June 2011.

Allende, A., McEvoy, J., Tao, Y., Luo, Y. (2009). "Antimicrobial effect of acidified sodium chlorite, sodium chlorite, sodium hypochlorite, and citric acid on Escherichia coli O157:H7 and natural microflora of fresh-cut cilantro". Food Control, 20, pp. 230-234.

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