日本黄曲霉1#菌株与苏-16菌株性能的对比

将日本黄曲霉1^#株与苏-16黄曲霉菌株进行了性能对比。结果表明，日本黄曲霉1^#的糖化酶活力比苏-16低16．7％，液化力略高，但酸性蛋白酶活力是苏-16的4倍。为了有利于黄酒生产，建议用日本黄曲霉1^#菌株代替苏-16菌株培养麦曲。(丹妮)     

福建醇化烟叶仓库空气中真菌多样性研究

为研究烟叶醇化仓库空气中真菌的多样性,选取龙岩东肖、龙岩红炭山、厦门东孚3座烟叶仓库1~5楼层的空气为研究对象,于2019年1—12月利用空气采样法对仓库各楼层空气中真菌进行月度采集、分离、鉴定。结果表明：（1）3座仓库各楼层空气中真菌的含量均呈现夏季多而其他季节少的规律,东肖、红炭山仓库空气中真菌的含量高于东孚仓库,其最高值分别是东孚仓库的10.9倍和9.4倍。（2）3座仓库空气中共分离获得835株真菌,归属于3个门、10个纲、54个属、158个种,且优势菌属为Penicillium、Cladosporium和Aspergillus,菌株数量占仓库空气中分离所得总菌株数比例大于10%的菌种为P.citrinum、P.corylophilum、C.halotolerans、C.cladosporioides和C.tenuissimum。韦恩图分析结果表明,东肖、红炭山、东孚仓库空气中分离获得的真菌种类数分别为68、92、68。其中,3座仓库共有的真菌为20种,东肖、红炭山、东孚仓库特有的真菌种类数分别为26、45、37。（3）一年中,仓库空气中真菌种类在冬季相对较多,而在春末夏初相对较少。C.cladosporioides、C.tenuissimum和P.citrinum是仓库空气中较为稳定存在的真菌菌种。     

制曲车间空气微生物及其对曲药质量的影响研究

研究了制曲车间不同环境场地、不同制曲季节及发酵室不同部位的空气微生物种群和数量差异及其对曲药质量的影响。结果表明:各环境场地间的微生物数量差异显著,不同环境场地优势微生物种群不同,对曲药质量有明显影响。     

Degradation of condensed tannins by rumen microbes exposed to quebracho tannins (QT) in rumen simulation technique (RUSITEC) and effects of QT on fermentative processes in the RUSITEC

In an earlier study it was observed that the rumen microbes from cattle which had never consumed tannin-containing diets do not have enzymes for degrading condensed tannins. In this study, rumen microbes were exposed to small amounts of quebracho tannins for 8 days using a rumen simulation technique (RUSITEC). The levels maintained in the RUSITEC were 0.1, 0.2 and 0.4 mg of the spray-dried quebracho powder (SDQT) per ml of the medium. After 8 days of tannin exposure, the liquor containing ‘exposed/adapted’ microbes from RUSITEC was incubated for 40 h without and with purified tannins of quebracho and Dichostachys cinerea leaves in in vitro gas method. There was no degradation of condensed tannins. The enzymes for degradation of condensed tannins were not induced in rumen microbes by exposure to different concentrations of tannins for 8 days in the RUSITEC. In the RUSITEC, SDQT significantly reduced the number of total protozoa, entodiniomorphs and holotrichs; effect was higher on holotrichs. There was no significant change in the levels of short chain fatty acid but the molar proportion of propionate was significantly higher and of butyrate significantly lower at 0.4 mg SDQT ml^?1. Significantly lower levels of ammonia in the medium was also observed on injection of tannins. Microbial mass production, calculated using ¹⁵N incorporation, was similar at 0.1 and 0.2 mg SDQT ml^?1 but significantly lower (13%) at 0.4 mg SDQT ml^?1. The dry matter digestibility of the feed (80% hay and 20% barley) was not significantly affected by SDQT.     

A microwire sensor for rapid detection of Escherichia coli K-12 in fresh produce

A rapid immunofluorescence method for foodborne pathogens in food systems using microwire sensor coupled with high frequency alternating current was developed. The method was intended to enrich and quantify E. coli cells internalized in baby spinach leaves. The targeted bacterial cells in the sample solution were captured on microwires in a diameter of 25 μm, and were bound to fluorescein isothiocyanate (FITC) labeled polyclonal E. coli antibodies. Fluorescent images of the FITC antibodies were obtained using a fluorescence microscope equipped with a charge-coupled-device (CCD) camera, and the fluorescent intensity (FI) was quantified through image processing. The capture of E. coli K-12 in PBS buffer was optimized when the electric field was generated at the frequency of 3 MHz and 20 Vpp with bacterial concentration of 10⁷ CFU/mL. The detection limit of our sensing device was determined to be 10³ CFU/mL. Field emission scanning electron microscopy (FESEM) was used to validate and visualize E. coli cells captured on the tip surface. The sensitivity and specificity of the developed sensor has been successfully validated by testing E. coli internalized in baby spinach leaves. The immunofluorescence detection has been completed within 15 min. Moreover, it was found that the enrichment process of E. coli cells using the dielectrophoretic force was rarely affected by food particles, which proved the sensing selectivity. The developed sensor is expected to meet the steady demand for a simple, rapid, highly sensitive detection approach to quantify the targeted microbes in food systems.

Industrial Relevance

There has been an increase in the number of foodborne illnesses linked to the consumption of fresh and minimally processed fruits and vegetables. Some E.coli strains such as E.coli O 157:H7, can cause a variety of diseases, including diarrhea, urinary tract infections, respiratory diseases, meningitis and more. In general, consumers wash the fresh produces under cold running tap water to remove any lingering dirt on the surface of the produces before eating or preparing. However, how do the consumers know if there is any possible pathogen hiding inside of the fresh produce after rinsing? It was reported from many researchers that, the E.coli internalization, which may occur when fresh produces intake E. coli containing water or manure from the soil, would be a main cause of the foodborne illness outbreak. To ensure the safety of drinking water, E.coli concentration cannot be higher than 1 CFU/mL. How can we detect such a low level of E.coli in an easy yet efficient way? To our knowledge, none of the traditional detecting approaches such as cultural based method, polymerase chain reaction(PCR), surface plasmon resonance (SPR) biosensor, and Latex Agglutination, has performed perfectly. Hence, a rapid and accurate technique for detecting foodborne pathogens in fresh produce is urgently needed in order to secure the food safety.To overcome this issue, a simple detection method for foodborne pathogens in food systems using the microwire sensor coupled with high frequency alternative current was developed. The sensitivity and specificity of the developed sensor have been successfully validated by testing with E. coli internalized inside baby spinach leaves. It was found that spinach particles rarely affect the performance of our sensing device, which shows a promising prospect of its application in food industries.     

高温堆积发酵工艺在浓香型双沟大曲酒生产中的应用

采用高温堆积发酵工艺生产浓香型双沟大曲酒，通过对堆积发酵过程中糟醅的水分、温度、淀粉、糖分、酸度变化规律的探索和堆积过程中微生物消长规律进行研究。结果表明，应用高温堆积发酵新工艺，不仅丰富了微生物的种类和数量，同时增加其代谢产物的种类和含量，增加了白酒中的香味成分，所产酒的香气更加幽雅、细腻；口味更醇甜、绵软、丰满、味长；且己酸己酯的含量增加了60～80mg／100mL。     

Chemometric Classification of L-Tryptophan Lots from Genetically Modified Bacillus amyloliquefaciens Strains

Four types of L-tryptophan lots produced by genetically modified B. myloliquefaciens strains II-V, which consisted of case-associated (11) with manifestations of EMS, control (16), and other lots (11), were compared by multivariate computer recognition programs (chemometrics) including HCA, PCA, KNN and SIMCA, as well as PLS. In HCA data analysis lots from strains III and V formed discrete clusters, and in PCA and SIMCA, both lots formed separated groups. Lots from strains II and IV were included in a group of lots from strain III. This indicated strains II and IV too were closely related to strain III. When strain vs case-associated control or other lots were compared by four methods, SIMCA provided adequate strain separation and strains were well grouped in case-associated or control lots.     

控制杂菌污染,提高酯化酶粗酶制剂的质量

在浓香型大曲酒生产中的酯化酶粗酶制剂生产过程易遭受杂菌污染而使酒质低下。该文用黄水调节培养基pH值的方法来控制杂菌污染。结果表明，用100％黄水调节培养基：pH值可使酯化率达到35．5％，合格率达100％，且无杂菌污染情况，感官鉴定良好。用于大生产中出酒率为39．0％，优质品率为26．4％，合格品率为78％。     

河南臭豆豉发酵微生物的分离鉴定

为了改变河南臭豆豉目前的现状,加速臭豆豉产品的工业化进程,从河南不同地区采集了5种农户自然发酵的臭豆豉样品,利用平板稀释分离实验,对自然发酵制成的臭豆豉的微生物组成进行了分析.结果表明:河南臭豆豉自然发酵的主要微生物为细菌类,经分离纯化、鉴定后,初步确定为枯草芽孢杆菌和地衣芽孢杆菌.     

Transport and fate of Cryptosporidium parvum oocysts in intermittent sand filters

The transport potential of Cryptosporidium parvum (C. parvum) through intermittent, unsaturated, sand filters used for water and wastewater treatment was investigated using a duplicated, 2³ factorial design experiment performed in bench-scale, sand columns. Sixteen columns (dia=15 cm, L=60 cm) were dosed eight times daily for up to 61 days with 65,000 C. parvum oocysts per liter at 15°C. The effects of water quality, media grain size, and hydraulic loading rates were examined. Effluent samples were tested for pH, turbidity, and oocyst content. C. parvum effluent concentrations were determined by staining oocysts on polycarbonate filters and enumerating using epifluorescent microscopy. At completion, the columns were dismantled and sand samples were taken at discrete depths within the columns. These samples were washed in a surfactant solution and the oocysts were enumerated using immunomagnetic separation techniques.The fine-grained sand columns (d₅₀=0.31 mm) effectively removed oocysts under the variety of conditions examined with low concentrations of oocysts infrequently detected in the effluent. Coarse-grained media columns (d₅₀=1.40 mm) yielded larger numbers of oocysts which were commonly observed in the effluent regardless of operating conditions. Factorial design analysis indicated that grain size was the variable which most affected the oocyst effluent concentrations in these intermittent filters. Loading rate had a significant effect when coarse-grained media was used and lesser effect with fine-grained media while the effect of feed composition was inconclusive. No correlations between turbidity, pH, and effluent oocyst concentrations were found. Pore-size calculations indicated that adequate space for oocyst transport existed in the filters. It was therefore concluded that processes other than physical straining mechanisms are mainly responsible for the removal of C. parvum oocysts from aqueous fluids in intermittent sand filters used under the conditions studied in this research.