So the aliens develop a food additive that will kill the entire population of earth. Now all they need is a way to put the additive into food that is distributed around the world. They should have bought stock in McDonald's but they decided to do it the villain way, by infiltrating a food processing center and spraying the additive on the food. Very implausible.
The food that they choose is miracle grain which is impervious to anything. It is developed by famous billionaire Marcus Mason (similar to Elon Musk). Mason is played by Alex Cord, who also played Michael/Archangel on "Airwolf." Mason is a billionaire seeking to make more billions by feeding the hungry. He is counting on the USA and other nations to be shamed into paying what he wants.
The alien Advocates happen to be watching the news when Mason announces his super-grain, and they just finished their poisonous food additive. A match made in hell? A couple of scenes of the aliens torturing humans and using them for testing poisons is pretty good. The people that wrote this show put a lot of effort into showing how evil the aliens were.
Once the aliens decide to poison the entire world population by using the miracle grain, they immediately take over the body of Marcus Mason's mistress, and then Mason, and then his wife. Then the aliens bring in more aliens to run the company, they take over the grain lab and start spraying the grains with poison. We are talking maybe 15 trays of grain?
A few days later, several ships full of thousands of crates of poisoned grain are about to leave port, when the good guys finally figure it out, and go after Mason. How did 15 trays of poisoned grain become several cargo ships full of grain, in a couple of days? Lazy writing.
Once again, in spite of the pompous Blackwood nearly missing the boat on what the aliens were doing, the good guys mostly win. It seems like every time Norton the internet whiz figures out what the aliens are doing, either Blackwood or Ironhorse refuses to cooperate, and then they spin their wheels until it becomes an emergency.
A lot of loose ends are never tied up in regards to all the aliens that were running the company, and the poisonous seed formula, etc. This episode is part of a trend of lazy writing on this show, where the aliens create a really dumb plan, and it almost succeeds because the "pathetic humans are so stupid."