The horse meat scandal was about 6-7 years ago now and affected several supermarket chains - it was down to unscrupulous suppliers. No doubt they're behind bars now?
Since then, very great care has been taken by Aldi and all other supermarkets to ensure that beef is indeed beef and nothing else!
The worst part of the scandal wasn't just that time-expired Dobbin had been burgered, it was that certain veterinary drugs had entered the food chain.