"西泽民凉拌菜" can be translated as "Xi Zemin's Cold Dish" (if referring to a specific dish created or associated with a person named Xi Zemin) or more generically as "Cold Dish by Xi Zemin" if emphasizing the originator. However, if "西泽民" is not a specific person's name but rather a brand or place name in this context, a more appropriate translation might be "Xizemin's Cold Dish" (assuming "Xizemin" is the correct pinyin representation of the Chinese characters and is used as a brand/place identifier).
In most casual or menu-based contexts, especially if the focus is on the dish itself rather than its originator, a simpler translation like "Cold Mixed Vegetables (Xizemin Style)" or "Xizemin's Special Cold Dish" could be used, depending on the specifics of the dish and the intended audience.
Since the exact nature of "西泽民" is not clear from the question, the most straightforward and general translation, assuming it's a brand or place, would be "Xizemin's Cold Dish".