Pesticides are widely considered as crop protection products, which are directly applied onto the vegetation or supplied through the soil in conjunction with nutrients, inside the plant and consequently inside the fruits. Remainders of drugs or transformation products can be found in human excretions. Additionally, people often thoughtlessly discard leftovers of drugs into the wastewater.
Part of the wastewater sewage sludge is distributed as fertilizer into the fields. The addition of antibiotics to animal feed is also a commonly known fact. Residues of these are used as dung and liquid manure on fields. Although it is not clear, there is chance for these substances to be absorbed by plants and passed along in the food chain. In this perspective, the study by the University of Paderborn gains attention.
Significance of Food Inspection
Many different pesticides are applied on tomato plants. Through this method, the spray chemicals end up directly on the fruit as well as inside the fruit indirectly through the nutrient transport when leached into the soil. In addition, organic fertilizers are widely used in animal husbandry albeit the consumers’ desire over unpolluted food. However, pesticides and fertilizers are essential to produce foods in the demanded quality. As a result, food inspection becomes indispensible to verify the presence of potential residues. Often these substances are temperature sensitive. Hence, sample preparation is crucial.
Sample Preparation with FRITSCH Mills
Each analysis needs the provision of a representative sample from the whole sample volume. Hence, as a rule, a product in larger quantities is generally made available and the addition of a representative sample to the analysis instrument through comminution and sample dividing needs to be ensured.
Cryogenic sample preparation of tomatoes for analytical purposes can be performed with the Mortar Mill PULVERISETTE 2 (Figure 1), wherein liquid nitrogen is used to embrittle chopped tomatoes (Figure 2). For this purpose, FRITSCH provides a stainless steel mortar bowl as accessories for the mortar mill. This bowl can be cooled down with liquid nitrogen and allows further addition of liquid nitrogen during the comminution if needed. This makes a complete cryogenic comminution possible with liquid nitrogen. A fine homogenous powder is produced after a few minutes (Figure 3).
Figure 1. Mortar Mill PULVERISETTE 2 with stainless steel mortar bowl.
Figure 2. Here the tomato pieces are floating in the liquid nitrogen.
Figure 3. Already after a few minutes a fine homogenous powder is obtained.
For further analysis or for further processing steps, a small representative amount of sample can be weighed in and prepared by this method.
This information has been sourced, reviewed and adapted from materials provided by FRITSCH GMBH - Milling and Sizing.
For more information on this source, please visit FRITSCH GMBH - Milling and Sizing.