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阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项。
Why does cream go bad faster than butter? Some researchers think they have the answer, and it comes down to the structure of the food, not its chemical composition－a finding that could help break away from some chemicals．Cream and butter contain pretty much the same things, so why cream should go bad much faster has been a problem．Both are small globules(小球)of one liquid which spreads throughout another．The difference lies in what's in the globules and what's in the surrounding liquid, says Brocklehurst, who led the research．In cream, fatty globules drift about in a sea of water．In butter, globules of a watery roads are locked away in a sea of fat．The bacteria(细菌)which make the food go bad prefer to live in the watery areas of the mixture．“This means that in cream, the bacteria are free to grow throughout the mixture,” he says, “when in butter, the bacteria are locked away in locked places buried deep in the sea of fat．Trapped in this way, those colonies cannot spread and rapidly run out．They also slowly poison themselves with their waste products．” “In butter, you get a self－limiting system which stops the bacteria growing．” says Brocklehurst．The researchers are already working with food companies eager to see if their products can be made to stand bacterial attack through changes of the food's structure．
Brockelehurst believes it will be possible to make something used in salad cream, for instance, more like that in butter．The key will be to do this while keeping the salad cream liquid and not turning it into a solid state．
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