Tantrums reaching a new level?

[minibmw2010]

DS is 2.5, not massively vocal yet, some words, maybe about 20. Has had a few tantrums but they're generally over soon enough if I put him down and ignore.

Tonight -

I'm still recovering from a shocking visit to Asda earlierto pick up snacks for car journey tomorrow. DS didn't want to get in trolley and it went downhill from there ... He went berserk, absolutely no other word for it, purple in the face, noises I've never heard before and kept trying to reach me. I kept him at arms length because he kept hitting me. He was obv starving as hadn't eaten dinner (am trying to be strong with if you won't eat you get no extra but he's uninterested by food so that's a struggle). Desperately upsetting. Lots of ladles walking last giving me consoling smiles/glances while lots of old people & men walked past tutting!! Ignored him till he calmed down and he grabbed me and cuddled me and kisses me ??

What should I be doing?

Maybe it was just a simple one-off case of him feeling really peed off that he was surrounded by food in a supermarket and was hungry?

Not saying you're doing anything wrong at all (I haven't got to that stage so definitely can't judge) but from his point of view it might have felt a bit like his nose was being rubbed in it - imagine if you couldn't eat before having a blood test or something and someone was eating some lovely buttery toast in front of you!