This special issue of the Frontiers Report focuses on the potential environmental, health, social and animal welfare implications of the uptake of novel meat and dairy alternatives, in particular... Show moreThis special issue of the Frontiers Report focuses on the potential environmental, health, social and animal welfare implications of the uptake of novel meat and dairy alternatives, in particular novel plant-based, fermentation-derived and cultivated products. A team of interdisciplinary experts has assessed the available evidence on the impacts of these alternatives in comparison with their conventional counterparts, identifying pertinent considerations for policymakers involved in regulating, investing in or providing other support for novel meat and dairy products and highlighting research gaps. Show less
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to... Show moreOptical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data. Show less
