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The use of organochlorine and organophosphorus pesticides has been prohibited due to their highly toxicity. In recent years, pyrethroids (PYRs) have been widely used in agricultural production and the environment due to their high efficiency and stability, but the residual hazards caused by their frequent use have become increasingly prominent. 3-Phenoxybenzoic acid (3-PBA) is one of the major metabolites of PYRs, which is an environmental estrogen with great potential harms. Pesticide residues have seriously affected people’s production and life, which has attracted extensive attention from researchers. PYRs and 3-PBA degrading bacteria have been widely reported, and microbial and enzymatic degradation is recognized as an effective method for reducing or removing pesticide residues from agricultural products and the environment. The continuous development of genetic engineering and molecular biology technology provides a new way to explore methods for reducing pesticide residues. In this article, we summarize the basic properties and residual hazards of PYRs and 3-PBA, and we review the current status of PYRs residues in agricultural products and the environment as well as recent progress in research on the modes of microbial metabolism and the mechanisms of microbial adsorption and degradation of PYRs. Moreover, we give an outlook on enzymes degrading PYRs and their genetic engineering in order to provide a reference for solving the problem of pesticide residues in agricultural products and the environment.

ObjectiveTo establish a culture-dependent rapid detection method for gas-producing spoilage bacteria in vinegar.MethodsOne kind of medium was screened out from six candidate media and modified. Then its specificity， accuracy， and sensitivity were determined， on which a detection method was proposed. This method was subsequently applied to assess heat sterilization conditions and preservative concentrations for vinegar products and to verify the detection effectiveness of vinegar products.ResultsA modified MRS medium that could specifically detect gas-producing spoilage bacteria in vinegar samples was proposed， with which negative results were obtained targeting at other 12 spoilage bacteria isolated from vinegar. The established method was adopted to examine 75 unknown vinegar samples and plastic bottle incubation method was used as control. Consistent results were obtained using both methods， however the detection rate of established method was 3-5 times faster than control， with a detection limit （initial bacterial count） ranging from 1 CFU to 10 CFU. The larger bacterial load is， the shorter detection time would be. And it will take only 1-2 d for high-contamination vinegar samples. Results also showed that sterilization at 75-85 ℃ for 5-15 min could effectively kill the gas-producing spoilage bacteria that is recalcitrant to common preservatives within their maximum allowable concentrations. The verification was in agreement with the actual situation.ConclusionThe constructed method features fast， specific， accurate， and sensitive. This study sheds light on detection and comprehensive control of gas-producing spoilage bacteria for vinegar enterprises.

Phenolic acid decarboxylase (PAD) (lyase, EC 4.1.1.102) catalyzes the conversion of phenolic acids such as coumaric acid, ferulic acid, caffeic acid, and glucosic acid that are widely distributed in plants into 4-vinyl derivatives. 4-Vinyl derivatives are not only high-grade fragrances, but also key precursors for the synthesis of other spices such as vanillin. Food spices are mainly chemically synthesized in the current market. By contrast, the biosynthesis method, which is characterized by single precursor substances, mild conditions and environmental friendliness, has broad application prospects, and biosynthesized spices are regarded as being equivalent to natural products. Therefore, using PAD for the biosynthesis of 4-vinyl derivatives is of great significance to supplementing the production pathway of this type of fragrance. In this article, PAD derived from microorganisms are summarized from five aspects: origins, molecular structure, catalytic mechanism and structure-function correlation, catalytic properties, and techniques to improve the catalytic efficiency.

Pyrethroids (PYRs) are widely used as pesticides due to low toxicity and high efficacy; however, PYRs residues have caused increasingly serious environmental and food safety problems. 3-Phenoxybenzoic acid (3-PBA), one of the major intermediate degradation products of PYRs, is more stable and toxic than the parent pesticides, and its residue can further aggravate environmental and agricultural product pollution. In recent years, filamentous fungal degradation of PYRs and 3-PBA has been reported, and research on this topic mainly focuses on strain screening, degradation characteristics, degradation pathways and localization of degradation enzymes. Unfortunately, key enzymes and their encoding genes involved in the degradation process are rarely reported. With the development of sequencing technology, molecular biology technology has provided a new strategy to mine PYR-degrading enzymes and their encoding genes in filamentous fungi. In this article, the basic properties, residues status and hazards of PYRs and 3-PBA are described. The filamentous fungi capable of degrading PYRs and 3-PBA, and their degradation pathways and degrading enzymes are reviewed. In addition, future prospects for the development of methods for screening and verification of degrading enzymes and their encoding genes are discussed. We expect that this review will provide a theoretical basis for understanding the degradation pathways and mechanisms of PYRs and 3-PBA by filamentous fungi and provide a reference for reducing residual pesticides in the environment and agricultural products.

China is a big producer and consumer of grains and oils. The development of high-yield grains is closely related to chemicals such as pesticides. With the improvement of people’s living standards, residents’ requirements for foods have changed from ‘security of output’ to ‘equal emphasis on quality and output’. In order to strengthen the management of grain quality and safety, it is urgent to comprehensively understand the status of pesticide pollution in grains and develop more efficient, convenient and rapid detection technologies. This paper briefly summarizes the characteristics of pesticides and pesticide residues, analyzes the current status of the use and residues of pesticides in raw materials for grains and oils in China, reviews the existing rapid detection methods and technologies for pesticide residues in grains, and compares the advantages and disadvantages of various rapid detection methods and products. This review is expected to provide a reference for quality inspection during grain purchase.

Chinese traditional fermented seasonings, essential to the culinary heritage of China, are produced through fermentation, resulting in a diverse range of unique flavors and aromas. The microorganisms involved in fermentation play significant roles in shaping the quality of these traditional fermented seasonings. The production of traditional fermented seasonings is affected by various biological and abiotic factors, presenting challenges concerning product quality and safety. This review investigates the impact of bioaugmentation technology on key Chinese traditional fermented seasonings, such as vinegar, soy sauce, sufu, doubanjiang, dajiang, and douchi. Additionally, the challenges and constraints linked to the implementation of bioaugmentation technology are discussed. The potential of bioaugmentation is highlighted by its ability to shorten the fermentation time, optimize raw material utilization, improve nutritional value, and enhance the quality parameters of these seasonings. This paper demonstrates an interesting convergence of traditional culinary heritage and contemporary technological advancements. [ABSTRACT FROM AUTHOR]

Histamine (HIS) is primarily formed from decarboxylated histidine by certain bacteria with histidine decarboxylase (hdc) activity and is the most toxic biogenic amine. Hdc, which is encoded by the hdc gene, serves as a key enzyme that controls HIS production in bacteria. In this paper, we characterized the changes in microbial and biogenic amines content of traditional Sichuan‐style sausage before and after storage and demonstrated that Enterobacteriaceae play an important role in the formation of HIS. To screen for Enterobacteriaceae with high levels of HIS production, we isolated strain RH3 which has a HIS production of 2.27 mg/mL from sausages stored at 37°C for 180 days, using selective media and high‐performance liquid chromatography. The strain RH3 can produce a high level of HIS after 28 h of fermentation with a significant hysteresis. Analysis of the physicochemical factors revealed that RH3 still retained its ability to partially produce HIS in extreme environments with pH 3.5 and 10.0. In addition, RH3 exhibited excellent salt tolerance (6.0% NaCl and 1.0% NaNO2). Subsequently, RH3 was confirmed as Enterobacter hormaechei with hdc gene deletion by PCR, western blot, and whole‐genome sequencing analysis. Furthermore, RH3 exhibited pathogenicity rate of 75.60% toward the organism, indicating that it was not a food‐grade safe strain, and demonstrated a high level of conservation in intraspecific evolution. The results of this experiment provide a new reference for studying the mechanism of HIS formation in microorganisms. Practical Application: This study provides a new direction for investigating the mechanism of histamine (HIS) formation by microorganisms and provides new insights for further controlling HIS levels in meat products. Further research can control the key enzymes that form HIS to control HIS levels in food. [ABSTRACT FROM AUTHOR]