(sooo...what is this about Peter not liking Russians?)

"The General Director of the [First Cadet Corps of St. Petersburg] regularly reviewed reports dealing with the meals served in the corps’ dining hall. One such report, dated June 12, 1761, greatly upset the Grand Duke [Pyotr Fyodorovich]. This report was authored by Captain-Lieutenant Friedrich Ploetz. According to the report… out of 454 Russian cadets, only 424 came to dinner and 408 to supper. On the other hand, out of the 139 German cadets (those of Estonia and Livonian heritage, as well as children of foreign officers serving in Russia) none were absent at dinner and only 4 at supper. Captain-Lieutenant Ploetz explained the high attendance rate of the German cadets and the low attendance rate of the Russian cadets as follows: the food cooked for the German cadets was “good” but for the Russian cadets, both at dinner and at supper, the pea-and-fish soup had sand in it. Also, the pike, which was served for the Russian cadets as the main course, often had a stench. It should be noted that the German cadets sat separately in the dining hall and had their own tables. Many of the officers and teachers at the cadet corps were of German heritage and, thus, likely sympathized with the German cadets.

The Grand Duke decided to rectify the negative situation in the cadet dining hall with regard to the Russian cadets. Under his initiative, on June 30, 1761, the cadet corps director, A. P. Melgunov, promulgated a special directive which stated, that Major Nikolai Fyodorovich Lepunov had been in charge of the quality of the food served in the cadet dining hall, but he had allowed a situation where the cadets were served, especially on “fasting” days, with undercooked food and fish that had “a foul smell.” “His Imperial Highness has ordered” that from now on Captain Ungern-Sternberg would also oversee the quality of food served to the cadets. We have no doubts that Baron Karl Karlovich von Ungern-Sternberg would have fulfilled the Grand Duke’s order. That Captain, even then, was an example to other officers at the cadet corps of how to diligently perform one’s duties and obey the orders of those in higher stations."

O. P. Vedmin, Adjutant-General of Peter III - Karl Karlovich Ungern-Sternberg, p. 17-18. (translated from Russian)