Halal sourcing has two separate problems, and buyers routinely solve only the first. The first is whether the product is genuinely halal in its ingredients and its production. The second, and the one that stops shipments, is whether the certificate that says so is recognised by the authority in the country you are selling into. Turkey is unusually well placed on both, because it has a large Muslim-majority domestic market where halal is the default rather than a special line, and because it built formal halal infrastructure rather than leaving certification to private bodies alone.
That infrastructure is the part worth understanding. The Standards and Metrology Institute for Islamic Countries, an OIC body based in Istanbul, publishes the OIC/SMIIC standards that an increasing number of member states use as their reference: OIC/SMIIC 1 for halal food itself, OIC/SMIIC 2 for the bodies that certify it and OIC/SMIIC 3 for the bodies that accredit those certifiers. Turkey created a public accreditation authority, HAK, as the sole body authorised to accredit halal conformity assessment bodies, and it began accepting applications in October 2019. The Turkish Standards Institution received the first accreditation in the world against OIC/SMIIC 2 at the end of that year.
The commercial consequence is that a Turkish certificate is more likely to sit inside a traceable accreditation chain than a certificate from a purely private scheme. It is not, however, a universal passport. Malaysia, Indonesia, the Gulf states and Singapore each maintain their own recognition lists, and Indonesia in particular has moved to a mandatory regime with a hard date. Getting the product right and getting the certificate accepted are two different projects, and both have to be finished before the goods move.