My dad was factory production manager at Neilson's Ice-cream Factory in Gypsy Hill, West Norwood, and they all were extremely proud of making the best icecream in the UK at the time - supplying Fortnum and Masons, etc, as well as lots of icecream vans. I used to go to work with dad on Saturdays sometimes, aged 5-7 in 1957-59, when we lived nearby, and be left in his office, watching him through a window while he checked out the production line in a white lab coat and hat. He was fanatic about hygiene - which you had to be in the 1950s. Whenever there were tummy bugs about in London, we had to soak our hands in bowls of disinfectant each time we used the toilet, or went into the bathroom.
He liked to be there for the end/start of each shift - so in school holidays, whenever the weather was good, we saw very little of him, as production would go to three shifts, 7 days a week. I saw my first control charts in that office - funny that the same quality controls did not hit the NHS until the late 1990s. That factory was in an old bus or tram depot, but had an international reputation for it's efficient layout. A lot can go wrong if food production has to go through too many bends, or areas where it is difficult to keep the temperature right or bugs out. Neilson's were famous for bringing Dairy Icecream out of Cornwall, and won many awards at the annual Royal Dairy Show - Dad crowned the Dairy Queen a couple of times.
In 1963, Neilsons in the UK (still then part of the Westons Group) was taken over by Lyons Maid, who moved Neilson's production to their main factory in Greenford, Middlesex, where they quickly changed recipes, production techniques, etc. Dad left a few years on for a new icecream adventure. He stayed in different aspects of international icecream production until 5 weeks before he died aged 83 in 2008. Having started at 12 in his dad's icecream co (Greentrees, Romford), he'd worked for 71 years in icecream.