In this recipe, we'll be examining an Escherichia coli cell membrane proteomics experiment. This will require a large file that was too big to host in this book's repository, so we'll use code to download it directly. Due to this, you will need to be online for this recipe to work. We'll also need a file of the target organism peptides, that is, the Escherichia_coli.pep.all.fa file, which can be found in the datasets/ch6 folder of this book's repository. Our main functions will come from the proteoQC library.