Weird problem with curry sauce For a family get-together, I bought 20 large containers of curry sauce from my favourite Indian restaurant - 15 Dansak and 5 Korma. I collected the sauces on Thursday evening. The containers were all hot to the touch. Then I un-wrapped and diced the appropriate amount of chicken thigh fillets. These were bought the day before, well in date and stored in the fridge. I browned off the chicken in batches with a little ghee and garlic. Then I put all the chicken in a big pan and boiled in water for around 25 minutes. Then I tipped all the sauces into two separate pans - one Dansak and one korma. The sauces were still quite warm. I then added the cooked chicken to the sauces, put the lids on and stored them in a very cold greenhouse overnight.

The following evening I took them to the party venue and warmed them up, simmering for a while, to be ready for the guests. Around 3 hours later almost all the Korma had gone, along with some of the  Dansak. At this point I decided to try some of the Dansak. Putting it in a bowl with some rice I noticed a very slight sour smell. I took a couple of mouthfuls and then I had a good sniff of what was left in the pan. Again it smelled a tiny bit funny so... To be on the safe side I removed the pan from the buffet and put it in the kitchen. Half an hour later I asked my friend to come to the kitchen to have a smell and tell me what he thought. Now it smelled pretty bad. It wasn't on any heat but was sort of fermenting by itself, with little light coloured bubbles. It smelled pretty bad (sour) so I put the pan outside. I was now quite worried that I might have poisoned some people. I went back and had a smell of what was left in the pot of Korma. This smelled just fine.

A couple of hours later I went outside to dispose of the contents of the Dansak pot. Now  smell was absolutely disgusting. Holding our noses, my friend and I tipped it into a double plastic bag and we could see that it was actually separating and was really horrible.

This was a couple of days ago. To my relief no-one has become sick. I can still 'taste' the horrible smell.

I have done this exact same thing several times before, with no problems at all. I just wonder if anyone might know what could have caused this to happen this time. It's really bugging me.
I think the times you did it with no troubles you used smaller portions, right? These big portions simply do not cool down quickly enough, and the temperature stays too long in the danger zone, say between thirty and sixty celsius. Bacteria grow very quickly around these temps, and so they spoiled your curries. Their waste is lactic acid or alcohol and carbondioxide, and that were the bubbles and the smell. You solve it by cooling down rapidly, so in smaller portions. The other option is that it stayed too long in the danger zone on the buffet, it was the last to go. Probably both... buffets are dangerous in the best of circumstances...in that case you also have to serve smaller portions on the buffet next time.