No abstract

Chinese chive ( Allium tuberosum Rottler) has potential risks associated with pathogenic bacterial contamination as it is usually consumed raw. In this study, we investigated the microbiota of Chinese chives purchased from traditional markets and grocery stores in March (Spring) and June (Summer) 2017. Differences in bacterial diversity were observed, and the microbial composition varied across sampling times and sites. In June, potential pathogenic genera, such as Escherichia , Enterobacter , and Pantoea , accounted for a high proportion of the microbiota in samples purchased from the traditional market. A large number of pathogenic bacteria ( Acinetobacter lwoffii , Bacillus cereus , Klebsiella pneumoniae , and Serratia marcescens ) were detected in the June samples at a relatively high rate. In addition, the influence of the washing treatment on Chinese chive microbiota was analyzed. After storage at 26°C, the washing treatment accelerated the growth of enterohemorrhagic Escherichia coli (EHEC) because it caused dynamic shifts in Chinese chive indigenous microbiota. These results expand our knowledge of the microbiota in Chinese chives and provide data for the prediction and prevention of food-borne illnesses.

This work demonstrates an application of ultrafast laser processing to engrave a grid pattern for evaluating mechanical properties. No observable changes in the material properties caused by laser engraving were confirmed if the grid pattern is engraved with laser energy of 0.21 μJ/pulse and pulse repetition rate of 1 kHz. The shape changes of grid pattern directly reveal whether the deformation accompanied with stretching is uniaxial or not. By analyzing the optical images of the grid pattern, Poisson ratio, Young’s modulus, and shear modulus of poly(dimethylsiloxane) (PDMS) with a weight percent of curing agent of 9% were estimated to be 0.49989 ± 0.00111, 1.45 ± 0.01 MPa, and 0.725 MPa, respectively. The comparison of the current results with the literature values suggests that the proposed method is appropriate to provide quantitative mechanical properties of soft materials with high accuracy.

Chicory leaves (Cichorium intybus) are widely consumed due to their health benefits. They are mainly consumed raw or without adequate washing, which has led to an increase in food-borne illness. This study investigated the taxonomic composition and diversity of chicory leaves collected at different sampling times and sites. The potential pathogenic genera (Sphingomonas, Pseudomonas, Pantoea, Staphylococcus, Escherichia, and Bacillus) were identified on the chicory leaves. We also evaluated the effects of various storage conditions (enterohemorrhagic E. coli contamination, washing treatment, and temperature) on the chicory leaves’ microbiota. These results provide an understanding of the microbiota in chicory and could be used to prevent food-borne illnesses.