The danger of mycotoxin contamination entering the food supply through post-harvest infection is of perennial concern to food safety experts. To explore the distribution of Penicillium expansum and diffusion of its mycotoxin, patulin, in blue mold-damaged pears, Pyrus bretschneideri Rehd. cv. Yali obtained from markets and orchards in China were artificially inoculated with P. expansum and assayed for patulin accumulation and degree of fungal colonization. The inoculated pears were incubated until the lesions were 5, 10, 20, or 30 mm in diameter. We sampled tissue at a range of distances from the lesion, measured the spread of Penicillium by plate colony-counting methods, and used UHPLC-MS/MS to detect and quantify the patulin concentration. More P. expansum colony-forming units were isolated from pears with a higher degree of decay. Farther from the lesion, the fewer P. expansum colonies were observed, and the lower the patulin content detected. We found a significant difference in the patulin content between samples due to lesion size, and also in tissue sampled 10 mm away from the lesion. In consideration of this finding, to ensure food safety, we recommend that when a blue mold rot lesion on pear is 5, 10, or 20 mm in diameter, 20, 30, and 40 mm beyond the lesion should be removed, respectively. If a lesion surpasses 30 mm in diameter, the whole pear should be thrown away.

This paper reviewed management of pesticide residues in China including laws and regulations, the supervision system, the standard system, and the quality and safety of agricultural products. The process of establishment and internationalization of standards for pesticide residues were also discussed. Results indicate that the progress of the management of pesticide residues has been steadily made in China. However, the following aspects which refer to updates to regulations, supervising efficiency, standard system, risk assessment, international cooperation and communication, should be further improved. China should draw lessons from international experience, and then establish its own management system, which focuses on pesticides controls by strictly following relevant laws and technical standards to ensure the quality and safety of agricultural products.

The aim of this work was to assess the effect of applying three different doses of fluxapyroxad on microbial activity, community structure and functional diversity as measured by respiration, microbial biomass C, phospholipid fatty acid (PLFA) and community-level physiological profiles (CLPPs). Our results demonstrated that substrate-induced respiration (on day 15) and microbial biomass C (on days 7 and 15) were inhibited by fluxapyroxad, but stimulation was observed thereafter. In contrast, fluxapyroxad addition increased the basal respiration and metabolic quotients (qCO2) and respiratory quotients (QR). Analysis of the PLFA profiles revealed that the total and bacterial biomass (both Gram-positive bacteria (GP) and Gram-negative bacteria (GN)) were decreased within the initial 15 days, whereas those as well as the GN/GP ratio were increased at days 30 and 60. Fluxapyroxad input decreased the fungi biomass but increased the bacteria/fungi ratio at all incubation time. Moreover, high fluxapyroxad input (75 mg fluxapyroxad kg–1 soil dry weight) increased the microbial stress level. A principal component analysis (PCA) of the PLFAs revealed that fluxapyroxad treatment significantly shifted the microbial community structure, but all of the observed effects were transient. Biolog results showed that average well color development (AWCD) and functional diversity index (H´) were increased only on day 60. In addition, the dissipation of fluxapyroxad was slow in soil, and the degradation half-lives varied from 158 to 385 days depending on the concentration tested.

In this study, the hydrolysis of the insecticide ethiprole in buffered solutions at pH 4.0, 7.0 and 9.0, respectively, and the degradation and adsorption-desorption behaviors of ethiprole in five agricultural soil samples from China were investigated. The half-lives under anaerobic conditions were faster than that in the aerobic experiment. Ethiprole was relatively stable under both acidic and neutral conditions while it was readily hydrolyzed under alkaling condition. The sorption of ethiprole on five soils was well described by the linear and Freundlich equation and mainly governed by soil organic matter. The exothermic process of ethiprole adsorption can also be well explained by physical adsorption. A weak adsorption capacity was observed in all soils, which could readily lead to leaching problems.

2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), the dominant benzoxazinoid hydroxamic acid in maize (Zea Mays L.), serves as important factors of resistance against insects and microbial diseases, allelochemicals used in competition with other plants. In this paper, a novel and simple method for the isolation and purification of DIMBOA from maize seedlings was developed. Frozen shoots from 7-d-old maize seedlings (1 000×g) were firstly defrosted and then were directly homogenized and extracted with ethyl acetate. The macerate was allowed to stand at room temperature (25±2)°C for 1 h to allow enzymatic release of DIMBOA from DIMBOA-glucoside. Then the ethyl acetate phase was filtered, dried and evaporated to dryness. The resulting light-tan, semicrystalline residue was stored at -20°C for 24 h. Upon recrystallization from acetone-hexane, a relative higher yield (0.58 g) of pure DIMBOA crystals was obtained compared with the yield afforded by Woodward methodology (0.26 g).