Not giving brand names of products

Until these past 3 nights of primetime TPIR with "Survivor", "Big Brother", and "The Amazing Race", I haven't watched the show for at least 2 years or so. I noticed that they showed the products but George (the announcer) never mentioned the brand names. It sounded really weird because they used to fully describe each product ("a sixteen ounce box of Rice-A-Roni, the San Francisco treat", etc.). I did hear George say "Cuisinart" for a product and they said the makes of the cars but that's about it. If there was a problem with them SAYING the brand name, it seems that they would also cover said name on the product but they didn't do that. Have they ever explained why they don't say the brand names? Just curious.