Dear madam,
It is possible sometimes that your salivary glands (organs that produce saliva) maybe producing less amounts of saliva. Another possibility is that the cleanliness of mouth is not maintained adequately leading to deposition of remnants of food on tongue and other areas of mouth leading to the present problem. Another problem might be that you maybe experiencing a problem with your intestines which can also lead to the present problem.
So kindly check with your dentist on possibilities and treatment options for your condition.
Next Steps
Visit a dentist nearby with all your previous medical records
Health Tips
Rinse your mouth after every time you eat something. That should help. All the best.