anandnk wrote:
Salmonella is a food-borne microorganism that can cause intestinal illness. The illness is sometimes fatal, especially if not identified quickly and treated. Conventional Salmonella tests on food samples are slow and can miss unusual strains of the microorganism. A new test identifies the presence or absence of Salmonella by the one piece of genetic material common to all strains. Clearly, public health officials would be well advised to replace the previous Salmonella tests with the new test. .
Which one of the following, if true, most substantially weakens the argument?
Summary
Logical Structure : Salmonella : food-borne microorganism --> intestinal illness --> Fatal, If not identified early.
Salmonella tests(Existing) :Slow and Miss some strains.
New Salmonella test uses new technique, using genetic mat.., can identify all the common strains.
Conclusion : Hence PHO need to replace this new test with the old ones to detect Salmonella.
Pre Thinking
We know this new test is better than the old one, but what about its result time.(Slow/Fast).
(A) The new test identifies genetic material from Salmonella organisms only and not from similar bacteria.
Irrelevant, Con. is about Salmonella detection only.(B) The new test detects the presence of Salmonella at levels that are too low to pose a health to people.
If that is the case we might need to discard food unnecessarily as it won't pose an issue. Hence PHO might not use it. But this might not be a best weaken choice, So let us check other options.(C) Salmonella is only one of a variety of food-borne microorganism that can cause intestinal illness.
Irrelevant, Same reason as option A(D) The new test has been made possible only recently by dramatic advances in biological science.
OFS(E) Symptoms of Salmonella poisoning are often mistaken for those of other common intestinal illness
OFSHence I will pick B.