I agree working mums who are bf has to carry many bags to work. I carry pigeon freezer bag and tote bag. Avent manual pump attached to 330ml size bottle, one storage cup, nursing bra, bb romper, photo, small wash cloth and extra breast pads can all be squeezed inside.
I wear normal bra with padding type and place breast pads to absorb bm in case. Feel nursing bra is soft and no padding so nipples may protude out under the work clothes. Only during pumping, use nursing bra.
The ebm flows direct into the attached bottle and once done, I will place the items back into bag and put entire freezer bag inside the freezer compartment of fridge. 10am, 2pm, 5pm do the same thing. By then, entire bottle is full and will take bag home. Reach home, transfer into storage cups and place them in the fridge.
If mummies really like to sterilize, get the pigeon portable model. I used to do that for #1 but it's really too time consuming. So for #2, I just ensure everything stays in the office freezer.
Let's persevere to give our kids the best nutrition.