No abstract

The sterile insect technique (SIT) is a biological control tactic that is used as a component of area-wide integrated pest management (AW-IPM) programs. The SIT can only be applied against disease-transmitting mosquitoes when only sterile male mosquitoes are released, and the blood-sucking and potentially disease-transmitting females are eliminated from the production line. For Anopheles arabiensis, a potent vector of malaria, a genetic sexing strain was developed whereby females can be eliminated by treating the eggs or larvae with the insecticide dieldrin. To evaluate the presence of dieldrin residues in male mosquitoes designated for SIT releases, a simple, sensitive, and accurate gas chromatography–electron capture detector (GC–ECD) method was developed. In addition, bioaccumulation and food chain transfer of these residues to fish after feeding with treated mosquitoes was demonstrated. The overall recovery from method validation studies was 77.3 ± 2.2% (mean ± relative standard deviation [RSD]) for the mosquitoes, and 99.1 ± 4.4% (mean ± RSD) for the fish. The average dieldrin concentration found in adult male An. arabiensis was 28.1 ± 2.9 µg/kg (mean ± standard deviation [SD]). A range of 23.9 ± 1.1 µg/kg to 73.9 ± 5.2 µg/kg (mean ± SD) of dieldrin was found in the fish samples. These findings indicate the need to reassess the environmental and health implications of control operations with a SIT component against An. arabiensis that involves using persistent organochlorines in the sexing process.

Plant uptake of toxins and their translocation to edible plant parts are important processes in the transfer of contaminants into the food chain. Atropine, a highly toxic muscarine receptor antagonist produced by Solanacea species, is found in all plant tissues and can enter the soil and hence be available for uptake by crops. The absorption of atropine and/or its transformation products from soil by wheat (Triticum aestivum var Kronjet) and its distribution to shoots was investigated by growing wheat in soil spiked with unlabeled or (14)C-labeled atropine. Radioactivity attributable to (14)C-atropine and its transformation products was measurable in plants sampled at 15 d after sowing (DAS) and thereafter until the end of experiment. The highest accumulation of (14)C-atropine and/or its transformation products by plants was detected in leaves (between 73 and 90% of the total accumulated) with lower amounts in stems, roots, and seeds (approximately 14%, 9%, and 3%, respectively). (14)C-Atropine and/or its transformation products were detected in soil leachate at 30, 60, and 90 DAS and were strongly adsorbed to soil, with 60% of the applied dose adsorbed at 30 DAS, plateauing at 70% from 60 DAS. Unlabeled atropine was detected in shoots 30 DAS at a concentration of 3.9 ± 0.1 μg kg(-1) (mean ± SD). The observed bioconcentration factor was 2.3 ± 0.04. The results suggest a potential risk of atropine toxicity to consumers.

The stability of novel meat pigments derived from heme‐enriched extract obtained from porcine hemoglobin was assessed. Four different ligands (sodium nitrite, 4‐methylimidazole, methyl nicotinate, and pyrazine) were used to produce spray‐dried, microencapsulated heme‐ligand complexes. The storage and thermal stabilities of the produced pigments were assessed, over a 6‐months storage period and across a temperature range of 25–75°C. Color measurements and evaluation were made on the dissolved pigments by ultraviolet–visible absorbance spectroscopy and CIELAB color space. All heme‐ligand complexes exhibited a stable red color across the storage period, except for the heme‐methyl nicotinate adduct, which color faded to brown after 30 days of storage. For thermal stability, only the heme‐4‐methylimidazole complex did not retain its red color beyond 55°C. The redness of the heme‐pyrazine complex showed improvement upon heating, which is proposed to be due to the degradation of polymeric heme‐pyrazine structure formed during the ligation process. Practical applications Due to the global effort to reduce nitrite addition in food product, there is an important interest to replace it in processed meat products, wholly or in part. Additionally, the perspective of optimizing the usage of an under‐utilized blood fraction is attractive for the meat industry. The development of a heme pigment derived from porcine blood thus presents a good commercial potential. Two important aspects of such product would be its stability upon storage, or during heat treatment to levels similar to what is used in processed, cooked meat products. This study presents the behavior for those two aspects of different heme‐ligand complexes, and compares the results obtained with a heme pigment produced from the traditionally used nitrite.