Surely you'll be supplied with warm clothing, gloves, boots etc? The only time I've worked in a cold indoor environment [freezer at an Antarctic research unit], all staff had to wear fur lined hooded suits and boots. You won't be in the chiller for 8 hours a day, as you'll have meal and toliet breaks.
Just keep sweets in an easily accessible pocket. If you take your test meter into chiller, then keep it in a pocket close to your body to keep it warm. I find that a breast pocket is ideal for this purpose when I'm working outdoors in cold weather on races, for example, which can mean being outdoors for several hours through the night in Lakes District / Peak District / Howgills in January.