Choking on food is a leading cause of accidental death in several populations, including children, people with intellectual/developmental disability, and older adults in residential care facilities. One contributor to choking risk is incomplete oral processing and failure to convert food to a cohesive, nonsticky bolus with a maximum particle size that will not block the airway. Clinical tests of mastication do not evaluate properties of chewed food boluses. We characterized expectorated boluses, after oral processing, using methods developed by the International Dysphagia Diet Standardisation Initiative (IDDSI).

Seventeen adults without dysphagia (seven women and 10 men), aged 23–55 years, chewed samples of a cracker, a raw baby carrot, and a circular, dome-shaped gummy candy. Chewing metrics were obtained up to the point when the person indicated that they were ready to swallow. The bolus was then either expectorated or swallowed; IDDSI tests were used to characterize the expectorated boluses.

Measures of chewing did not differ between spit and swallow conditions. Expectorated cracker and carrot boluses had maximum particle size consistent with IDDSI Level SB6 Soft & Bite-Sized foods or lower. The gummy candy samples remained at IDDSI Level RG7 Regular food consistency.

This study suggests that expectorated ready-to-swallow boluses are representative of boluses that are swallowed and that oral processing in adults without dysphagia typically results in boluses at IDDSI's Level SB6 or lower. IDDSI's testing methods provide a practical method for evaluating oral processing by characterizing expectorated ready-to-swallow boluses and may guide food texture recommendations for persons who have increased risk of choking.