Reliability of human senses for evaluating texture of food

Abstract

The measurement of physical properties often depends on senses or feelings of practitioners. For example, dietitians adjust the viscosity of fluids for people with dysphagia to prevent aspiration at institutions for the elderly or hospitals. In such circumstances, a mistake could put lives of the patients in danger. To investigate accuracy of practitioners' sense, we asked 50 dietitians to select one sample fluid with the closest viscosity to potage soup, yogurt, or jam. The viscosities of the samples were adjusted with an Instant food thickener (IFT) product. Without references of real food, less than 50% of subjects selected the correct sample. The correct answer ratios were significantly higher in subjects with the 15~25 year experience of nutritional guidance than those with less than 5 years. Only around 20% of subjects selected the right viscosity sample when compared with the reference. These results suggest that senses of an experienced individual are not always reliable. And it must be necessary to introduce an appropriate assessment process such as the Line Spread Test (LST), although it still has certain limitation in applicability.