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While it is improbable that food particles are navigating their way through your eustachian tube, you could have a blockage in the nasal passage preventing equilibration of pressure between the middle ear and the nasal passages.
As your livelihood depends upon your hearing, ask for a referral to an ENT specialist
. They have the special tools needed to visualize the nasal sinuses
and can help diagnose the true reason for your difficulties.
In the meantime, as flushing
alleviates your symptoms temporarily, continue. You may be able to "flush" the foreign body that you believe is causing your symptoms.