Express it as your personal opinion.
I'm hesitant, too, to express mine. I might potentially be asked by DC Administrators to resign my account for its irresponsible and harmful heresy. Yes, there are good practices for food safety. But, the distinction has to be noted whether it is commercial or in the home.
At a restaurant, it's not a precautionary if, but an absolute when, you will some day serve a bad chicken. The difference in practicing food safety is whether one patron goes home with a queasy stomach or whether 300 people report sick, including 1 child who dies. The restaurant is boarded and all its well-meaning employees are blacklisted.
In my kitchen, if I should be so unlucky one day to buy, cook and eat a bad chicken, it makes absolutely no difference to me whether the side of salad I ate with it was cross-contaminated with sloppy food safety practice. Even if the dinner was prepared with level 2 hazmat standards, I'd still get sick from the meal.
At my home, as well as a circle of some friends who vary in their culinary skills, it is a given that we've gathered to share, whether its voluntary or inadvertent. That includes any misfortunes like salmonella.
Cook with her. But, if your urge to tell her how is insistent, I would google a list a excuses to cancel and cook more for yourself. Sorry, JD. I think tact is a virtue, but if it has motive, I think it's an affront to the person even if I believe the reason to be right. Don't give advice unless asked; always feel free to give opinion.