Well, technically Mustaffa Centre is the biggest Halal supermarket with the biggest Halal Frozen Food Section. Just that they don’t put it in their branding that Halal is their primary selling point. They have other more compelling marketable selling points, and they are not dependent primarily on the Malay Muslim market for sales.
Mustaffa does not sell pork or alcohol in its supermarket.
They do however have in-house pharmacies that sell medication and health supplements. Medication and supplements if you understand fiqh are Halal because the intent of their creation is not to intoxicate or harm, but meant to heal and improve health by being used specifically through controlled processes of application or ingestion for their safest use for specific purposes. If you intentionally use such products wrongly or for purposes other than what it was specifically intended for, then that is not the problem of the product but the problem of the person’s niat and akal.
So to contend that Mustaffa might not be halal because it sells medications and health supplements that might not be accredited with Halal certification is not an argument of fiqh but an argument of personal orientation.
Not all products require a Halal certification to be Halal for human consumption. You want to have Halal certified boobs for breast milk is it? Or Halal certified water treatment plants and piping for Halal tap water? Your mother must call MUIS to certify her kitchen before you eat her food is it?
If you want to go along the extreme line of only buying food with Halal Certification or from a place with Halal certification then how to shop at NTUC Fairprice, Sheng Siong, Prime, Giant or Cold Storage because they all sell alcohol and pork? So the salary of the workers there also not Halal is it, because the shop they work at sells pork and alcohol? That ‘must have Halal certification for everything’ is a ridiculously unnecessary and extreme mindset to have.
Plastic is made from fossil petrochemicals which includes the decayed liquified carcasses of dinosaurs and ancient animals that include ancient pigs so does that mean you cannot use plastic bags to pack your food, basically it is wrapping your food in the repurposed decayed animal carcass of an animal that was not slaughtered but left to rot? Of course not right, the remains of these animals have been processed naturally and artificially to the point that they are seen as chemicals and not as animal products.
Let us all please use our akal and common sense. If a Muslim is the one buying the ingredients ensuring they are not Haram, preparing and cooking the food. And they have no intention of causing you harm or to cheat you, their intention is only to make food for you to enjoy consuming and make a clean living for themselves. That food you buy is Halal because of their niat and they tanggung (accepting accountability) for their product. And their income is Halal. You do not need a certificate to tell you that the food they make is Halal.