What does that even mean?
I strongly suspect McDonalds can't change their processes and supply chain quite that quickly, nor are they likely to take the PR hit now.
McDonalds doesn't use either one, and stopped using the "pink slime" stuff in 2011: https://www.cnet.com/news/pink-slime-in-burgers-mcdonalds-hi...
> "McDonald's does not use lean beef trimmings treated with ammonia, what some individuals call 'pink slime,' in our burgers, and hasn't since 2011," McDonald's website also stated.