We weren't strict at all and never restricted any foods. We did wait until after 6 months (really the risk of allergies is in starting any solids before 6 months). After 6 months, you can give them anything and you shouldn't delay offering any particular foods. That's actually way outdated advice. There is lots of scientific evidence to support that offering all foods is less likely to lead to allergies. For example, kids who have things like nuts withheld as babies (post-6 months) are actually more likely to develop a nut allergy later in life. So I wouldn't restrict or delay anything as long as your LO is 6 months. The only things we didn't feed were added sugar, salt, honey (risk of botulism before 1 year) and whole nuts (choking risk before they have all their molars), but obviously none of that was related to allergies. Our daughter's first meal was roasted carrots and parsnips, mash and a yorkshire pudding, so obviously a mix of lots of different types of foods. The only time I'd delay offering any food is if you or your partner have an allergy to it.
If you are going to have an allergic reaction, more than likely you'll be able to pinpoint what it is fairly easily. Our daughter had a suspected reaction to pumpkin seeds (pumpkin seed butter) - within 2 hours of eating them, her face swelled up, she was covered in a rash, puffy eyes and projectile vomiting. It happened twice and it was really obvious what caused it (it was the only thing she'd had in common on those two occasions). On advice of GP, we avoided it until after a year and then re-introduced it. She was fine. No reaction now. I have no idea if it was a true allergic reaction or maybe a strange reaction to food poisoning if it had gone bad (she'd had it before several times with no problems). Anyway, it was easy to work out and easy to eliminate until we were ready to try it again. It didn't change how we generally offered new foods though.