Ruling on eating in the mosque
Nothing prohibits eating of food in the mosque as long as it will not be messed up (dirty) or release bad odor as a result of doing so. Moreover, those who stay in the mosque for I’tikaaf eat their food there and present Iftaar (food for breaking fast) for those who are fasting in many mosques without difficulty or blame. This can be found in the ruling of Imam Nawawi, ‘Verdict No. 76’ that eating in the mosque is allowed, nothing prohibits it. However, it is important for the one eating to spread something so as to maintain and guard the mosque from droppings of small pieces of food and the like. And that there shouldn’t be bad odors like garlic and onion. If not, it is disliked.