Kitchen waste disposal comes up in bathroom sink downstairs

[Josef]

I need to know if there is any type of piping configuration that I can do downstairs, to keep food particles from kitchen upstairs, from coming up into bottom of sink, without having to tear the wall out to see what kind of handy work was done in connecting sink to drain? And if I have to tear wall out what can I do?
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[bab]

Hi Joesef.R u in the uk. has tis problem just started.how long hve u lived there.

 

[Josef]

No I'm in the USA. Just moved in with my mother-in-law a few months back. This bathroom hasn't been used, everyone has been afraid of it. I guess because it is in the basement. I've been fixing it up, but everytime the garbage disposal is used upstairs in the kitchen you will find food particles that came up in the sink. Any ideas?[/b]