Food should not reheat more than 1 time - Why ?

The quality decreases each time food is reheated because of changing in the moisture and sensory characteristic such as taste, texture and palatability.  Furthermore, Food poisoning bacteria will start to multiply when chilled food is reheated to temperatures above 5ºC. They will stop multiplying when the food reaches to above 60ºC.  When keeping of leftovers is unavoidable and cooked foods cannot be used within 4 hours, from the safety standpoint it may be refrigerated at ≤5°C for 3-4 days or frozen for longer storage rapidly. In this position the leftover foods that have been cooled rapidly should be reheated at least 73.8°C and hold at that temperature at least for 2 minutes before consumption. But, most people do not carefully measure internal temperature. On the other hand there are bacteria that produce toxins or spores in unsafe temperature that are harmful to human health. While the bacteria are killed during reheating, the toxins and spores are unaffected by the heat. So, the best practice is only reheating perishable food once after it has been cooked.

To maintain good quality of food and to prevent bacteria from producing toxins which cause food poisoning or intoxication..

While reheating the bacterial spores present in the food may germinate. So when you reheat it for the second time, these bacteria will die and they will release some toxins from their body. These toxins can't be removed and will cause foodborne intoxication.

First of all you need to let it cool down, before putting it in the fridge. If you put hot food in a fridge all that does is raise the temperature inside the fridge and turn it into the perfect incubator for bugs - which is not great for the food that is already in the fridge.

You should only reheat leftovers once. The more times food is cooled and reheated the greater the potential for food poisoning as bacteria may multiply because the food is cooled too slowly, and might survive because the food isn't reheated properly.

As long as you reheat the leftovers to at least 165°F each time, the food's technically safe to eat. However, the thing to keep in mind is that each reheat results in a decrease in the quality of the food: things get overcooked, dry out, or there's a big change in texture.

It's best practice to just reheat the amount you think you'll eat in one sitting and err on a smaller portion to begin with. Remember, you can always reheat more if you're still hungry!

Also remember that leftovers should be eaten with four days, so if you don't think you'll finish them within that time period, consider freezing the leftovers instead.