Hello, my name is***** and I have over 20 years of experience as a veterinarian.
I am sorry to hear that your kitty Jack ingested food that may have been exposed to fumes from a flea bomb.
The good news is that is was in a different room and hopefully not much of the spray ended up on the food. I wouldn't feed him any more of it though.
Most flea bombs contain pyrethrins and these can be toxic for cats. The are much more sensitive to these insecticides than dogs are.
If this is a pyrethrin based product common symptoms of this toxicity are drooling, nausea, diarrhea, dilated pupils, tremors, incoordination and in very severe cases seizures.
The problem with this toxin is if they start to experience symptoms and cannot eat and drink they get very dehydrated and worsen quickly.
If the tremors are very bad they can cause an increase in body temperature and muscle toxins which can cause brain damage and kidney failure.
So if their body temperature rises and they are tremoring consistently we put them on fluids to bring down the body temperature and flush out the muscle toxins.
If actual seizures occur he will need intravenous medication for that.
At home one thing that can be done is decontamination. If it has been less than 6-8 hours you can give activated charcoal at a dose of 1GRAM (NOT MILLIGRAMS) per pound of body weight orally. This will absorb some of the toxins and decrease his ability to absorb and digest the toxin.
Nursing care is important too. That includes keeping him quiet and away from stairs so he doesn't fall and hurt himself, and helping him eat and drink if he is uncoordinated. Keep an eye on body temperature. We need to get concerned if he has a rectal temperature more than 103.5F. Keep him in a quiet area as the more he is stimulated the more likely it is he will tremor or seizure.
If he seizures he must be seen by a veterinarian.
There is nothing that you can do at home for that.
As far as how long his symptoms will last, that will depend upon how much he ingested.
Usually symptoms last 2 to 3 days if the exposure is small.
If this is an extreme exposure then symptoms can last a couple weeks.
Very rarely there is long term damage.
My hope is that his exposure was so small he won't show any symptoms, but I wanted to give you possible symptoms of toxicity so you know what to watch for and get him examined and treated should they occur.
Please let me know if you have any further questions.