Effects and fate of chloramphenicol, methoprene, and narasin in yellow mealworms (Tenebrio molitor)

Insects for feed and food have received considerable interest because of their potential as an alternative protein source. As these insects could be susceptible to diseases or pests, use of veterinary medicinal products could be advantageous in mealworm rearing. However, in the European Union no products are currently approved for this purpose and monitoring their use to safeguard food safety and the food chain is required. This study investigated the effects of three substances that were included in the substrate used for mealworm rearing: chloramphenicol (100 mg kg −1 ), methoprene (10 mg kg −1 ), and narasin (70 mg kg −1 ), on mealworm ( Tenebrio molitor ) weight gain and survival after 24, 72 and 168 h of exposure and quantified residues of these compounds. The investigated substances did not affect mealworm weight gain or survival. Chloramphenicol (26 – 562 µg kg −1 ), methoprene (13 – 20 µg kg −1 ) and narasin (328–698 µg kg −1 ) were detected with LC-HRMS and LC-MS/MS methods in exposed mealworms. Metabolite screening did not reveal major metabolites relevant to residue monitoring.