How could a negative result be given for lipids and proteins after sophisticated laboratory analysis of pretzles fat-free yogurt and beans?

A negative result for lipids and proteins in fat-free yogurt and beans could occur if the laboratory analysis was conducted improperly, such as using inadequate sample sizes or incorrect testing methods. Additionally, the specific formulations of the fat-free yogurt may have effectively removed measurable fat content, while the beans could have been processed in a way that reduced their protein levels. It's also possible that the samples were mislabeled or contaminated during testing, leading to inaccurate results.