Bioaccessibility and Risk Assessment of Trace Elements in Mealworms Using Continuous On-Line Leaching Coupled with Inductively Coupled Plasma Mass Spectrometry

Mealworm (Tenebrio molitor) is considered a sustainable protein source and classified as a non-novel food by Health Canada. However, data on safe consumption levels based on bioaccessible metal(loid) concentrations are limited. In this study, a modified continuous on-line leaching method (COLM) coupled with inductively coupled plasma mass spectrometry (ICPMS) was developed to quantify bioaccessible Cr, As, Se, and Cd in mealworm powder. Samples were packed into a transparent polypropylene flash column and sequentially leached with artificial saliva and gastric juice at 37 °C to simulate gastrointestinal digestion, with continuous monitoring of released elements by ICPMS. The proposed method required approximately 70 min per sample as opposed to over 2 h with conventional batch methods. Whereas the bioaccessible concentration of Se was negligible, 13 ± 5 µg/kg Cr, 18 ± 5 µg/kg As and 18 ± 6 µg/kg Cd were released, representing 14%, 15%, and 26% of their total concentration, respectively. Mass balance was verified for Cr, As, Se, and Cd, demonstrating the reliability of the method. Additionally, different sources of elements were revealed by plotting the temporal profile of one element versus that of another element for each gastro-intestinal fluid. A preliminary quantitative risk assessment indicated that adults can safely consume 105 g mealworm per day. Although no significant noncarcinogenic risk was identified, the incremental lifetime cancer risk of 5.2 × 10−6 for As and 1 × 10−6 for Cr exceeds or equals the Ontario threshold, indicating potential concern. This study is the first to apply the COLM to mealworm while integrating bioaccessibility data for a more realistic risk assessment. However, back-pressure issues result in a relative standard deviation up to 39%.