#17 - Any food that is not sterilized and sealed can contain

[Administrator]

Complete Question Explanation

Must Be True. The correct answer choice is (D)

The first two sentences establish only two possibilities: food is either sterilized and properly sealed, or it is not. Sterilized and sealed food contains no bacteria. If food is not sterilized and properly sealed, however, then it can contain disease-causing bacteria (although it does not necessarily contain such bacteria).

We also know that acceptable food preservation techniques involve either sterilizing and sealing food (which would contain no bacteria) or slowing the growth of disease-causing bacteria. This second option does not involve sterilization, so it can contain disease-causing bacteria. The last sentence mentions that some acceptable food preservation techniques may destroy natural food enzymes. However, it is impossible to connect this fact to the rest of the stimulus since we do not know which food preservation technique(s) destroy these enzymes.

The correct answer to a Must Be True question must pass the Fact Test, i.e. it must be provable by the information contained in the stimulus.

Answer Choice (A): While it is true that some food preserved by acceptable methods is free of disease-causing bacteria, we do not know whether all such food is free of bacteria. In fact, some methods merely slow the growth of disease-causing bacteria, suggesting that some acceptable methods do not ensure that food is bacteria-free.

Answer Choice (B): This answer choice cannot be proven given the information provided. The final sentence of the stimulus tells us that some preservation methods destroy enzymes, but provides no information as to which preservation methods destroy enzymes. It is possible that all of the food preservation methods that destroy enzymes do sterilize the food.

Answer Choice (C): Once again, the last sentence cannot be connected to the rest of the stimulus. Since we do not know which food preservation methods destroy the enzymes, we do not know which method is more or less likely to cause food to discolor.

Answer Choice (D): This is the correct answer choice. Any food that is not sterilized and sealed can contain disease-causing bacteria, even if the food was preserved by an acceptable method. This is because some acceptable methods only slow the growth of disease-causing bacteria.

Answer Choice (E): Any food that is sterilized and sealed contains no bacteria. This does not mean that bacteria-free food requires an acceptable preservation method, such as sealing and sterilization. This is a Mistaken Reversal of the first sentence. It is possible that some food is naturally bacteria-free.

[Nina]

I guess i did this one wrong because of my wrong diagramming. I think the first sentence in the stimulus can be diagrammed as:
St=sterilized
B=contain bacteria

Not St B
then, the contrapositive one will be:
No B St
and, because sterilize belongs to acceptable method, it seems to me that answer E is correct.

Is there anything wrong with my diagramming?

Thanks a lot!

[Steve Stein]

Hi Nina,

The issue is this: The author provides that any food that has not been sterilized can have bacteria (potentially). Your diagram suggests that any food that has not been sterilized does have bacteria. If that were the case, answer choice E would be correct.

I hope that's helpful! Let me know whether it's clear--thanks!

~Steve

[r miller]

ok, first, am i correct that you are referencing S4, q 17, not sec 3?

next, keep in mind that, even with questions where diagramming is used, or where formal logic is incisive, it is always a good idea to have an intuitive grasp of what the stimulus is saying. in other words, diagramming is not a magic solution; you still have to understand the question intuitively. sorry about that.

now, let's look at the question.

first of all, understand that the first sentence says CAN contain bacteria, not that it does contain bacteria. that tends to invalidate your translation, as it is possible that if it isn't sterilized, then it may yet or still contain no bacteria. thinking about it intuitively and logically, this should make sense. another way of looking at it, the first sentence could equally well be diagrammed as "not st -----> not b", because the first sentence leaves open that alternate possibility.

in any event, this is one that it is perhaps better to understand intuitively. if we do that, we should see that A is too strong - some methods do not prevent all bacteria. B is wrong - those methods may sterilyze. C we simply do not know. D is certainly true, in the sense that it must be true that it could be true. and, E, we've discussed - in fact, reading it carefully and intuitively, in addition to what we've said already, there are certainly many foods that began with no bacteria and didn't need to be preserved, at least as far as we know.

tx and good luck!!

just looked at a posting. once again, steve said it better and more succintly!!

[Nina]

Hey Steve and Miller,

Thank you both very much for your precise analysis! Very very helpful

[jm51]

Hi I have a question about conditional statements in this question. I understand that "Any" indicates a conditional relationship in the first sentence, but why is the second sentence conditional as well? Is "once" equivalent to "if"?

Thanks for your help!

[Robert Carroll]

jm,

A conditional statement expresses the fact that one thing (the necessary condition) must exist whenever another thing (the sufficient condition) exists. Think about the second sentence this way: is it possible for food that is sterilized and properly sealed to contain any bacteria? Based on what the sentence says, that's not possible; so all food that is sterilized and properly sealed contains no bacteria. Thus, for food, being sterilized and properly sealed is sufficient to prove that containing no bacteria is necessary.

Robert Carroll