Just pack some extra and hand it out to your co-workers. A bite from a tasty sandwich will kill all negative comments.
Last year, I did some teaching in a class with refugees. Schools don't provide lunches here, so all had to bring their own. I've tasted the most exotic food last year - and they were all happy and proud to give me a small bite. As well as they shared lunches (= tastes from their homeland!).
Menno