I already reported what I believe to be a mistake. Here both smaczny and pomidor are either in the genitive case or in the animate/personal accusative case. It should obviously be the inanimate accusative for things like tomatoes. Treating the tomato as a living thing seems very colloquial at best and should not be featured here. But, that's my opinion.
This is not Genitive, it's an Accusative form of an animate noun, which is identical to Genitive.
English Wiktionary says that Accusative is "pomidor (in colloquial Polish also pomidora)". I'd say that this 'colloquial Polish' is in fact the norm. I have never heard "Jem pomidor" apart from discussions about grammar. Not once in my life.
Most vegetables and fruits are considered grammatically animate without any reason. Some other foods, and some beverages as well. Another group of such nouns are ones connected with technology. With the technology ones, the percentage of people treating them as animate will rather be smaller than those treating food as animate.