Teaching a solid 'leave it' to a Lab who thinks everything is food — progress is slow

This is the generalization problem and it's extremely common — 'leave it' in the kitchen is a different skill than 'leave it' outside in a dog's brain. You need to re-teach from scratch outdoors but you can compress it fast: start in your yard with boring distractions, then parking lots, then high-distraction parks. Use higher-value treats outside than inside (real chicken, cheese) because you're competing with dead birds. Also — 10-month-old Lab is peak impulse-control disaster age. This will genuinely get easier at 14-18 months just from maturation.

The management piece matters too while you're training: keep him on a short leash near anything gross so he can't self-reward by getting the thing before you can stop him. Every time he succeeds in eating the disgusting thing, it reinforces the behavior faster than your training can counteract.