I found this glitch in 0.50 patch by accident few days ago.
It requires a disinfectant spray and an item you want to consume (food, morphine, water bottle or canteen). Open inventory and start consuming an item, for example, you press "eat all" on rice. While the character is performing the animation you use disinfectant spray on some other (or the same) item in your inventory. After the animation is finished, rice will not disappear from your inventory and you can use it again. Same happens with morphine, bandages etc.