Methyl bromide: 1-year dietary study in dogs

Area of Science:

• Toxicology
• Food Safety
• Environmental Health

Background:

• Methyl bromide (MB) is a fumigant used in food production.
• Human dietary exposure to MB is estimated at 0.00125 mg/kg/day.
• Safety assessments are crucial for fumigated food products.

Purpose of the Study:

• To evaluate the safety of methyl bromide (MB) through a long-term feeding study in dogs.
• To determine the no-observed-effect level (NOEL) for MB in a dietary exposure context.
• To compare canine exposure levels with estimated human dietary exposure.

Main Methods:

• A one-year feeding study was conducted using beagle dogs.
• Dogs were fed diets fumigated with MB at varying doses.
• Methyl bromide consumption was calculated using time-weighted averages (TWA), accounting for degassing and consumption rates.

Main Results:

• Canine MB consumption in low-, mid-, and high-dose groups ranged from 0.06 to 0.28 mg/kg/day.
• No significant differences were observed in clinical observations, body weight, feed consumption, ophthalmology, clinical pathology, urinalysis, organ weights, or pathology between control and MB-treated groups.
• The NOEL for MB was determined to be at least 0.28 mg/kg/day.

Conclusions:

• The no-observed-effect level (NOEL) for methyl bromide (MB) in dogs was established at a minimum of 0.28 mg/kg/day.
• This NOEL is approximately 200 times the average estimated human dietary exposure.
• The study supports the safety of MB-treated foods under the tested conditions, indicating a substantial safety margin.