I don't know if you will be involved in the business on a day to day basis or if you want to start the same as a side thing - if its the latter I would advice you think very carefully about it.
they both involve highly perishable products, for the milk my take is you buy the milk on an order basis, get guys you can supply to first before bringing in the milk but its very risky, the milk supplied in the initial containers is the best because after the first container is done water is used to miraculously increase the milk quantity.
for the chips take care so that you do not end up spending more keeping the chips warm - at times it might be better to dip them in oil on an order basis.
they are interesting businesses but very challenging at the scale you are looking to start at.