Judging from its appearance, fresh beef has a glossy finish and a uniform red color; Meat that has been refrigerated for a period of time may appear slightly pale, lacking vitality and luster; Smell it, fresh beef has a normal odor, while refrigerated beef has a slight fishy smell; Pressing with your fingers, fresh beef is elastic and the indentations can be immediately restored; And those that have been refrigerated may not recover as quickly! Out of curiosity, I decided to use electron microscopy to observe and compare its microscopic morphology to see if there are more differences. Now, let's start the formal experimental part.

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Figure 1. Scanning electron microscopy image of fresh beef after being frozen once