Monday, July 4, 2011


Though the E.coli food poisoning episode has become just another quirks of history, it is difficult to forget the tragedy so easily considering the lives lost and people affected gravely by this little known pathogenic microorganism. It is a great relief to see the culprit product identified as organic sprouts from a German processor and how much damage this high profile industry is going to suffer due to this incidence is any body's guess. Now that the processor and the product that caused this episode have been identified, what next? Do we have sufficient wherewithal to avoid a repeat of another such calamity? Another little known fact is that this microorganism, derived from its innocuous cousin found commonly in feces, is resistant to more than 12 antibiotics currently used to fight infection in humans. Food pathologists have the onus to find out how a harmless bacteria like E.coli can assume such monstrous proportion, the reasons for the same and ways and means to prevent such transformation in nature.

The genetic sequence of the bacterium in question (a wholly new version of a strain of E.coli called O104:H4) has been found by scientists in Germany and China to contain at least eight genes that make it resistant to the majority of antibiotics. Many of the patients with HUS will need kidney transplants or require dialysis for the rest of their lives. The source of the tainted bean sprouts has been traced to an organic farm in northern Germany. The owner claims not to have used cattle manure, nor any of the three dozen or so non-organic additives widely employed in organic farming. Apparently, the only ingredients were seeds and water. The usual procedure for sprouting is to steam the selected seeds in drums at a temperature of 38ÂșC. Such conditions are ripe for breeding bacteria. The question is how the O104:H4 got there in the first place? The usual route is via animal faeces that have contaminated the water used for sprouting, or from manure used directly as organic fertiliser. But both have been ruled out. By all accounts, the farm also complied with the industry's highest standards of personal hygiene. The conclusion is that the seeds themselves must have been contaminated before hand. Microbiologists have long known that E.coli can bind tightly to the surface of seeds and even penetrate them, and then lie dormant for months. On germination, the population of bacteria can expand 100,000 times or more. Apart from contaminating the seeds, the bacteria get inside the stem tubers as the seeds begin to sprout. No amount of washing can then eradicate the bugs completely.

If the seeds used for sprouting are responsible for the contamination, why not evolve effective technology to treat and destroy them? If irradiation is not considered for consumer foods for fear of backlash, there should be no objection to subject the seeds to radiation sterilization before being used for sprouting. Alternately knowing well about the ability of E.coli to adhere to seed surface tightly, is it not possible to evolve a pre-treatment process for the seeds that will loosen the bacterial cells for subsequent washing? Probably some thing positive in this direction can be expected to happen, thanks to this unfortunate episode in Europe.

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