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Herein, a well-designed hydrophilic tetracycline-imprinted polymer with high selectivity was synthesized with a three-dimensional carbon nanocomposite of graphene oxide (GO) and carbon nanotube (CNT) by a green synthesis method of freeze-drying. The synthesized materials with super selectivity, which could distinguish high similar structural analogues of tetracycline (TC) and oxytetracycline (OTC), and the maximum adsorption capacity for TC (MW 444.44, 19.31 mg g−1) was 3-fold greater than its structural analogue of OTC (MW 460.43, 6.48 mg g−1). The synthesized materials were characterized by Fourier-transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), and thermogravimetry analysis (TGA). The adsorption mechanism and adsorption performance of the synthesized materials were detailed studied via the adsorption isotherms, adsorption kinetics, competitive adsorption, and selective adsorption experiments. A method was established by using the synthesized materials as the adsorbent for solid-phase extraction (SPE) of TCs residues in food samples and then detected by high-performance liquid chromatography (HPLC). Under the optimum conditions, the detection limit of this method (MDL) was 0.127 μg kg−1. The extraction efficiency of this method was performed in three real samples (milk, chicken, and fish) that spiked with tetracycline of three levels (5, 10, 20 μg kg−1). The results showed good recoveries ranging from 85.58 ± 0.19 to 116.87 ± 8.92% (S/N = 3), respectively.

BACKGROUND Diethylstilbestrol (DES) residues are harmful to human health because of their potential carcinogenic properties. Therefore, it is important to develop a fast and efficient pretreatment method to prevent their harmful effects on human health and the environment. RESULTS In this paper, two types of magnetic molecularly imprinted polymers (MMIPs) of DES were prepared by bulk polymerization and the sol-gel method, respectively. The synthetic materials were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. Adsorption capacities of the bulk and sol-gel MMIPs were investigated. A rapid detection method was developed using the two types of MMIPs as sorbents, coupled to high-performance liquid chromatography, for the determination of DES residues in milk samples. Under optimized conditions, the limit of detection (S/N = 3) of both methods for DES was 2.0 μg L-1 ; and the linear response range to DES was 0.1-500 mg L-1 . The milk samples were analyzed according to this method with good recoveries of 88.3-97.6 and 90.5-103.5% for the two types of MMIPs, respectively. CONCLUSIONS The method described had high sensitivity and high selectivity, and could prove to be a new method for the rapid determination of DES residues in milk samples. © 2019 Society of Chemical Industry.

The reduction of salt (sodium chloride) in fermented sausages is motivated by the positive association between excessive intake of sodium and some diseases. However, pathogens control and shelf life of fermented sausages is of vital importance when salt is reduced. In this study, we investigated the impacts of an IIa bacteriocin-producing strain, Lactobacillus plantarum LPL-1, on the composition of bacterial community in low-salt fermented sausages by using a culture-independent high-throughput sequencing approach. Meanwhile, impacts of LPL-1 on physicochemical characteristics of low-salt fermented sausages were investigated. Our results showed that LPL-1 changed the bacterial community composition, reduced community diversity and inhibited the growth of spoilage bacteria during fermentation and ripening of low-salt fermented sausages. After fermentation, Lactobacillus was the most abundant genus with the proportion over 90% in sausages which inoculated with LPL-1. We predicted microbial metabolism related to nutrients transport and metabolism enhanced in sausages by inoculating with LPL-1. We also found that the decrease of pH and tyramine, putrescine and cadaverine and total biogenic amines content in sausages inoculated with LPL-1. These findings indicated that L. plantarum LPL-1 can be applied as starter culture to improve the safety of low-salt fermented sausages.