Lady GaGa's father is furious after his restaurant's hygiene rating was downgraded.

Joe Germanotta was so angry he took to Twitter to vent his frustrations and reveal the hygiene inspector's identity after his New York eatery Joanne Trattoria was shifted down from an A rating, partly because there was a ''bad potato'' on the premises.

He wrote: ''Great story of NYC making progress, money and corruption. We had a bad potato in a bin with 40 good potatoes.

''It wasn't being served to a customer, it was raw, and when the inspector pointed it out we threw it away. How many bad veggies do you toss?

''Regardless, the inspector gave us 7 points for a bad potato in a storage bin on our health department inspection, that shifted us from an A to a B or Grade Pending, inspector said it was our choice. (sic)''

Joe then posted a list of all the violations his restaurant - which features recipes created by Gaga, real name Stefani Germanotta - received and slammed the inspector for his ''harsh'' assessment.

He tweeted: ''Here's my violations at 10:40 pm after the kitchen has been closed for 40 minutes. Potato Peeler 5 points - We were cleaning

''Bad Potato in storage bin - 7 points - It wasnt being served

''Ice Scoop not in a storage holder, it was in the dish machine - 5 points

''Wash hands sign at waiters station - 2 points - I'll put one up tomorrow, but we use this as a water station, not a hand sink.

''He took our A and left B or Grade Pending sign, our choice to display. Seems a little harsh. (sic)''

Last year, Gaga said her father's restaurant was to blame for her putting on weight because every time she visits she can't help but indulge in the ''freaking delicious'' pizza and pasta he serves up.