The issue of halal meat is one of importance in Islam, however in recent times with the advent of modernisation Muslims have gone away from tradition methods of slaughtering. This has now caused much confusion, with differing opinions as to what is considered halal meat.
When there is confusion on any Islamic matter, we should always refer back to Allah and His Messenger, as Allah (swt) says,
فَإِن تَنَازَعْتُمْ فِي شَيْءٍ فَرُدُّوهُ إِلَى اللّهِ وَالرَّسُولِ
Ya ayyuha allatheena amanoo ateeAAoo Allaha waateeAAoo alrrasoola waolee al-amri minkum fa-in tanazaAAtum fee shay-in faruddoohu ila Allahi waalrrasooli in kuntum tu/minoona biAllahi waalyawmi al-akhiri thalika khayrun waahsanu ta/weelan
(And) if you differ in anything amongst yourselves, refer it to Allah and His Messenger [Surah An Nisa’ 4:59]
There are numerous verses (ayaat) and prophetic narrations (ahadith) commanding Muslims to eat that which is lawful (halal) and to leave that which is unlawful (haram).
Allah (swt) says in the Qur’an
يَا أَيُّهَا النَّاسُ كُلُواْ مِمَّا فِي الأَرْضِ حَلاَلاً طَيِّباً
Ya ayyuha alnnasu kuloo mimma fee al-ardi halalan tayyiban wala tattabiAAoo khutuwati alshshaytani innahu lakum AAaduwwun mubeenun
O mankind! Eat of that which is lawful and good on the earth [Surah Al Baqarah 2:168]
يَا أَيُّهَا الَّذِينَ آمَنُواْ كُلُواْ مِن طَيِّبَاتِ مَا رَزَقْنَاكُمْ
Ya ayyuha allatheena amanoo kuloo min tayyibati ma razaqnakum waoshkuroo lillahi in kuntum iyyahu taAAbudoona
O you who believe! Eat of the lawful things that We have provided you with [Surah Al Baqarah 2:172]
يَسْأَلُونَكَ مَاذَا أُحِلَّ لَهُمْ قُلْ أُحِلَّ لَكُمُ الطَّيِّبَاتُ
Yas-aloonaka matha ohilla lahum qul ohilla lakumu alttayyibatu
They ask you (O Muhammad SAW) what is lawful for them (as food). Say: “Lawful unto you are At-Tayyibaat (all kind of Halal foods) [Surah Al Maidah 5:4]
The Messenger (saw) said:
إِنَّ اللَّهَ طَيِّبٌ لاَ يَقْبَلُ إِلاَّ طَيِّبًا
“Allah is pure and only accepts that which is pure” [Sahih Muslim] #2393
الْحَلاَلُ بَيِّنٌ وَالْحَرَامُ بَيِّنٌ
“That which is lawful is clear and that which is unlawful is clear” [Sahih Muslim] #4178
So it is common knowledge that Muslims only eat or drink that which is halal, to the point even the disbelievers (kuffar) have come to know that alcohol and pork is prohibited for a Muslim. As this is one of the topics known by necessity;
Many food types are halal in their original state such as fruits, vegetables, and sea food, other food type such as meat from chicken, sheep or cattle are only lawful if killed or slaughtered in the right manner.