PrepTest 137

Incorrect. The stimulus notes that some acceptable food preservation techniques involve slowing the growth of disease-causing bacteria, so this answer choice is disproven by the stimulus.

Incorrect. There are acceptable food preservation techniques that sterilize and seal food, and there are acceptable food preservation techniques that destroy enzymes. While that doesn't establish there are techniques that do both, it certainly leaves open that possibility, so this answer is unsupported.

Incorrect. The final statement notes that some of the acceptable techniques also destroy enzymes leading to discoloration, but it doesn't establish that this is more likely to be done in foods that have been sterilized than in foods that used a different method of preservation (namely, the techniques involving the slowing of bacterial growth).

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
not Sterilized OR not Sealed → Can contain bacteria
Sterilized AND Sealed → not Bacteria
Acceptable food preservation technique → (Sterilizing AND Sealing) OR (Slowing growth of bacteria)
Acceptable food preservation technique-some-Destroy food enzymes that cause spoilage/discoloration

Answer Anticipation:
First, note how we diagrammed the first conditional. Since the sufficient condition is "not sterilized and sealed," that translates to anything missing either of those parts of the process triggers the rule. If something is sterilized but not sealed, then it counts as "not sterilized and sealed."

Those first two statements seem to be the reverse of each other, which would make them a biconditional when combined, but there's a bit of a shift between actually containing no bacteria and not having the possibility of containing bacteria ("can contain"), so we aren't going to treat it as a biconditional.

The convoluted nature of that third conditional makes it pretty hard to work with—we don't know if food preserved with an acceptable technique has been sterilized, sealed, or treated to slow bacterial growth. That food is at least one of them, but we don't know which. As such, it's hard to see how we can combine it with that last quantified statement, even though they share a term and should be combinable.

This is a long way of saying we don't have a good anticipation for this question, so we need to get to the answers ASAP and do our work there!

Answer Explanation:
The first conditional rule in the stimulus states that any nonsterilized food (and any food not sealed, but that's a separate consideration) can contain bacteria—including foods preserved by a nonsterilizing acceptable method. This answer is supported by that first conditional statement (by itself—no other statement is needed to prove it), so it's the correct answer.

Key Takeaway:
When you're not seeing any inferences in a Must Be True question, don't be shy about heading to the answers and working through them by comparing them to the stimulus. If you don't see the inference in 10-20 seconds, don't waste more time—it's not ideal to head into the answers blind, but it's better than staring at a stimulus for 2 minutes and not getting closer to a correct answer.

Incorrect. Based on the first conditional, any food that contains no bacteria must have been sterilized and sealed. And while there are acceptable food-preservation techniques that involve sterilizing and sealing, that doesn't mean that all techniques that involve sterilizing and sealing are acceptable. (As an example, dumping nuclear waste into a food can and sealing it probably kills the bacteria, but it's almost certainly not acceptable.)