I would love to suggest that disposable uniforms are useful, (as we sell them) but have to agree with the majority of comments above.
Disposable clothing is much more prone to damage, due to its low cost material, possibly increasing the risk of physical contamination, especially in environments such as butchery. Staff generally do not like wearing it as much as laundered uniform as it doesn't look smart.
At best, i would have thought that a disposable plastic apron would be the way to go. But laundering clothing will be much cheaper in the long term, as you may well find that each member of staff uses several aprins in a single shift.
If you're concerned about environmental impact of the detergents, several chemical suppliers provide biodegradable laundry detergents, which can now be used at low water temperatures. If you balance the cost and environmental impact of these more environmentally friendly detergents against the cost and impact of disposable clothing, the detergent is most likely to win out every time.