grocery budget responsibility

Would like some advice on how all of you allocate grocery budgets to your helper? is it everyday or weekly? i am not too confident if they can handle keeping so much money and be accountable efficiently. How does a full time couple delegate the grocery budgets to their helpers or for that matter, even stay at home but busy moms allocate budgets? does the budget also include mini bus/taxi usage to go upto say Wellcome/PnS? or do you buy her an octopus card? Pardon me for asking such details, but i just want to know if helpers are responsible enough to manage buying exactly what is needed in the house or do you have cases where they just go over board buying too much stuff (as its not their money anyways...so "why care" kind of attitude).

I actually got my DH a credit card (supplementary to mine) which has a low limit, around $10,000. Guess it is still a lot but she has been with me for a long time and I totally trust her. She does all the shopping mostly at ParknShop so it is easy to keep track of all receipts. I also give her some cash for buying things at the market. She writes everything down and I calculate everything in great detail. Never had a problem.