Step 1: Understanding the Concept:
Food labeling regulations define specific terms to describe the nutritional content of meat products.
Terms like "lean" and "extra lean" are legally regulated based on the maximum fat and cholesterol content per serving.
Step 2: Detailed Explanation:
According to standard regulations established by agencies like the United States Department of Agriculture (USDA) and adopted internationally:
Lean Beef: A beef product can be labeled as "lean" if a 100-gram serving contains less than 10 grams of total fat, less than 5 grams of saturated fat, and less than 95 milligrams of cholesterol.
Extra Lean Beef: A beef product can be labeled as "extra lean" if a 100-gram serving contains less than 5 grams of total fat (which is less than 5%), less than 2 grams of saturated fat, and less than 95 milligrams of cholesterol.
Therefore, an extra lean muscle beef product must have a total fat content of less than 5%.
Step 3: Final Answer:
The fat content in an extra lean muscle beef product must be less than 5%.