European Journal of Nutrition & Food Safety

Aims: This study was conducted to detect the presence of cyanide in popular fruit and vegetable smoothies and juices marketed as raw and natural.

Study Design: Eleven (11) popular varieties of drinks were analyzed for total cyanide (_TCN).   Drinks contained raw vegetables and fruits, flax seeds, whole apples with seeds, raw almond milk, and pasteurized almond milk as ingredients.

Place and Study Duration: Samples were collected from health food eateries located within Las Vegas, Nevada (USA) during the summer of 2017.

Methodology: Fifty milliliters (mL) of a homogenized smoothie and juice drink and 1 gram of flax seeds were subjected to the above-referenced methods for sample preparation per USEPA Methods 9012B (digestion) followed by USEPA method 9014 (colorimetry). 

Results: The highest _TCN was detected in drinks containing raw flax seed followed by unpasteurized raw almond milk, then fresh whole apple juice.  No _TCN was observed in drinks that contained none of the above mentioned items (e.g. flax seed, raw almond milk) or those utilizing pasteurized ingredients.

Conclusion: This study observed that _TCN is present in smoothies and juices containing raw flax seeds, fresh whole apples, and/or unpasteurized almond milk. Concentrations were detected as high as 341 μg L^-1 in commercially available smoothies containing vegetables, raw flax seeds, almond milk and fruits. Smoothies with vegetables, fruits, unpasteurized almond milk, and no flax seeds contained 41 ug L^-1 _TCN, while similar smoothies with pasteurized almond milk contained negligible to 9.6 ug L^-1 CN^-. Unpasteurized almond milk and raw flax seeds were the major sources of _TCN in drinks.  With the increased demand for raw and natural foods, there is a potential sublethal exposure of _TCN by consumers.