They tried to sweep up the rice between weddings to reuse it and throw it again. But it didnt matter to get all of it up until later just to save time on fully cleaning the whole hall until it would be used as the mess hall later. Which saved even more time since they didn't need to bring any more for the rice pudding for desert.
The screenshot didn't upscale very well, but it got the job done. Go figure, using tape instead of film would result in this choppy mess. Friggin' cheap ass Paramount.
To be clear, I wasn't criticizing your picture. It's got lots of pixels and stuff. It was more a comment on the set design/maintenance corners that were cut because "no one will see that at 480i resolution. Now we've got 1080 remasters and allllll kinds of stuff are being revealed lol.
Or each grain of rice is a Q, just paying a visit. An ensign tried to vacuum up the rice before the ceremony and was turned into a bowl of petunias, so Janeway took the hint and left the rice alone.