Hi. My 10 Month Old Son Just Drank About 30

Hi. My 10 month old son just drank about 30 cc of spoiled formula milk prepared about 10 hrs back. This happenned 1hour back. Residual milk in the bottle suggests that it had started to sour. However, he drank it out of the sipper with satisfactory acceptance. problem is that he is recovering from dengue with falling platelet (1.2 lakhs)and absolute neutrophil counts(740) Please help!!!