What does fortification refer to in food processing?

Fortification in food processing specifically refers to the practice of adding nutrients to food products in amounts that are higher than what is naturally found in those foods. This is done to enhance the nutritional value of the food, aiming to prevent deficiencies in the population or promote overall health. For instance, vitamin D is often added to milk, and iodized salt has potassium iodide added to it to prevent goiter in the population.

Fortification differs from other practices such as simply replacing lost nutrients, which typically occurs during food processing where some nutrients may diminish due to handling or cooking. Adding naturally present nutrients does not constitute fortification, as this simply involves restoring the food to its original state rather than enhancing it beyond natural amounts. Similarly, retaining nutrients through cooking focuses on preserving the nutritional content of food without adding any new elements. Thus, fortification is clearly defined by the intention to increase nutrient levels beyond what nature provides, making that choice the correct answer.