Avoiding Cross Contamination

Processing samples form an integral part of the registration pathway for pesticides, but have you ever stopped to consider how laboratories go about this vital step?

Imagine trying to skin a melon that has already been frozen for transport without contaminating the flesh inside the melon with any pesticide residues that may be on the skin. Cross contamination of residues must be avoided at all costs, as the laboratory routinely analyses residues down to 0.01 mg/kg, an amount which is equivalent to one second of time in three years and four months.

Attempting to hold a large round object steady to take the outer skin layer off while not touching the inside flesh is harder than it sounds and extremely time consuming. Always up for a challenge, we went out to our local supermarket to buy fruits to test out various methods. 

The sample prep team can now wield a cleaver with deadly accuracy, splitting each fruit into 8ths, from where a bread knife can be used to slice off the skin – resulting in restaurant quality presentation of separated skin and flesh. All this, carried out under GLP conditions with clean gloves to prevent cross contamination.

The sample prep team at Battelle have not only encountered this problem, but have also had to consider how to destone olives and split kernels from maize cobs, to name but a few. Our experts have solved many problems which may not be immediately obvious.