If the packaging of the food specifically states that it is "not suitable for microwaved cooking if heating," it is essential to follow those instructions to ensure safety. Ignoring such warnings can lead to adverse consequences, including the risk of fire, explosions, or uneven heating that may not kill harmful bacteria.
The reason some foods come with this warning is that their packaging or composition may not be microwave-safe. This can include materials that may melt, release harmful chemicals, or catch fire when exposed to microwave radiation.
Even if the food can be eaten hot or cold after refrigeration, it doesn't necessarily mean it can be safely heated in the microwave. The manufacturer likely designed the product to be consumed without microwave heating due to the specific materials used in the packaging or the composition of the food.
To heat the food safely, consider using other heating methods, such as conventional ovens, stovetops, or boiling water. Always refer to the package instructions for the recommended heating methods, and if in doubt, contact the manufacturer for clarification. Your safety should always take precedence, so it's best to heed any warnings or instructions provided by the food manufacturer.