Evaluation of pesticide residue dynamics in Chinese cabbage, head cabbage and cauliflower.

Pesticide residues from the time of application until harvest were analysed for 20, 17 and 18 active insecticidal and fungicidal substances in Chinese cabbage, head cabbage and cauliflower, respectively. In total, 40 mathematical models of residue degradation were developed using a first-order kinetic equation, and from these models it was possible to forecast the action pre-harvest interval for a given action threshold for low-residue production in Brassica vegetables as a percentage of the maximum residue level. Additionally, it was possible to establish an action pre-harvest interval based on an action threshold of 0.01 mg kg‒1 for the production of Brassica vegetables for baby food. Among the evaluated commodities, the speed of residue degradation was highest in head cabbage, medium in Chinese cabbage and lowest in cauliflower. The half-lives of pesticide in various vegetables were also determined: they ranged from 1.55 to 5.25 days in Chinese cabbage, from 0.47 to 6.54 days in head cabbage and from 1.88 to 7.22 days in cauliflower.

Use of saline waste water from demineralization of cheese whey for cultivation of Schizochytrium limacinum PA-968 and Japonochytrium marinum AN-4.

Saline waste water from demineralization of cheese whey was used as the main component of waste saline medium (WSM) for cultivation of thraustochytrids. The suitability of WSM for cultivation of Schizochytrium limacinum PA-968 and Japonochytrium marinum AN-4 was evaluated by comparison with cultivation on nutrient medium (NM) in shake flask and fermenter cultures. Biomass productivities achieved in WSM for the thraustochytrids were comparable with those in NM for both shake flask and fermenter cultures. The maximum total lipid content (56.71% dry cell weight) and docosahexaenoic acid productivity (0.86 g/L/day) were achieved by J. marinum AN-4 grown on WSM in shake flask and fermenter cultures, respectively. A cost estimate of WSM suggests that this medium could result in lower production costs for thraustochytrid biomass and lipids and contribute to the effective reduction in saline diary process waste water.

Production of apple-based baby food: changes in pesticide residues.

Apples represent the main component of most fruit-based baby food products. Since not only fruit from organic farming, but also conventionally grown fruit is used for baby food production, the occurrence of pesticide residues in the final product is of high concern. To learn more about the fate of these hazardous compounds during processing of contaminated raw material, apples containing altogether 21 pesticide residues were used for preparation of a baby food purée both in the household and at industrial scale (in the baby food production facility). Within both studies, pesticide residues were determined in raw apples as well as in final products. Intermediate product and by-product were also analysed during the industrial process. Determination of residues was performed by a sensitive multi-detection analytical method based on liquid or gas chromatography coupled with mass spectrometry. The household procedure involved mainly the cooking of unpeeled apples, and the decrease of residues was not extensive enough for most of the studied pesticides; only residues of captan, dithianon and thiram dropped significantly (processing factors less than 0.04). On the other hand, changes in pesticide levels were substantial for all tested pesticides during apple processing in the industrial baby food production facility. The most important operation affecting the reduction of residues was removal of the by-products after pulping (rest of the peel, stem, pips etc.), while subsequent sterilisation has an insignificant effect. Also in this case, captan, dithianon and thiram were identified as pesticides with the most evident decrease of residues.

Comparison of diazinon toxicity to embryos of Xenopus laevis and Danio rerio; degradation of diazinon in water.

The aim of this study was to determine the toxic effect of diazinon (organophosphate insecticide) to embryos of Xenopus laevis and Danio rerio. The 96-h LC50 values showed higher toxicity of diazinon for X. leavis in standard solution (9.84 mg/L) compared to the pond water (12.64 mg/L). Teratogenic index for diazinon was 1.3 and 1.6, respectively. The 96-h LC50 diazinon values demonstrated similar sensitivity of embryos D. rerio (8.21-9.34 mg/L) and X. laevis in standard test solutions. Our results reflect that direct application of diazinon into the water can be associated with significant risks to aquatic organisms.