Their 5 stars hotels can make Singapore 5 stars hotels look like fading stars! You do not have to worry about this.
On the whole, water and food in the hotels are OK. I had diarrhoea from food eaten in 5 stars hotel in HK,and London! So your luck or misfortune in case the food handlers were sick!
But DO NOT drink water from the streets. I would suggest drinking bottled water from proper vendors. But I had water from Sikh temples and was OK!