What about food with unclear ingredients or E-numbers?

Doubtful: be careful Food & drink Quran · 1 Hadith · 1

Short answer

If you do not know whether an ingredient is lawful, the matter is doubtful. The Prophet ﷺ taught that between the clear lawful and the clear unlawful are doubtful matters, and whoever avoids them has protected his religion. Check the label, look up the source of codes such as E471 or E441, or contact the maker. If it stays unclear, leave it.

Evidence

Quran

ٱلَّذِينَ يَتَّبِعُونَ ٱلرَّسُولَ ٱلنَّبِىَّ ٱلْأُمِّىَّ ٱلَّذِى يَجِدُونَهُۥ مَكْتُوبًا عِندَهُمْ فِى ٱلتَّوْرَىٰةِ وَٱلْإِنجِيلِ يَأْمُرُهُم بِٱلْمَعْرُوفِ وَيَنْهَىٰهُمْ عَنِ ٱلْمُنكَرِ وَيُحِلُّ لَهُمُ ٱلطَّيِّبَٰتِ وَيُحَرِّمُ عَلَيْهِمُ ٱلْخَبَٰٓئِثَ وَيَضَعُ عَنْهُمْ إِصْرَهُمْ وَٱلْأَغْلَٰلَ ٱلَّتِى كَانَتْ عَلَيْهِمْ ۚ فَٱلَّذِينَ ءَامَنُوا۟ بِهِۦ وَعَزَّرُوهُ وَنَصَرُوهُ وَٱتَّبَعُوا۟ ٱلنُّورَ ٱلَّذِىٓ أُنزِلَ مَعَهُۥٓ ۙ أُو۟لَٰٓئِكَ هُمُ ٱلْمُفْلِحُونَ ﴿١٥٧﴾

Those who follow the messenger, the Prophet who can neither read nor write, whom they will find described in the Torah and the Gospel (which are) with them. He will enjoin on them that which is right and forbid them that which is wrong. He will make lawful for them all good things and prohibit for them only the foul; and he will relieve them of their burden and the fetters that they used to wear. Then those who believe in him, and honour him, and help him, and follow the light which is sent down with him: they are the successful.

Hadith

1 Sahih al-Bukhari 52

Narrated An-Nu'man bin Bashir: I heard Allah's Messenger (ﷺ) saying, 'Both legal and illegal things are evident but in between them there are doubtful (suspicious) things and most of the people have no knowledge about them. So whoever saves himself from these suspicious things saves his religion and his honor. And whoever indulges in these suspicious things is like a shepherd who grazes (his animals) near the Hima (private pasture) of someone else and at any moment he is liable to get in it. (O people!) Beware! Every king has a Hima and the Hima of Allah on the earth is His illegal (forbidden) things. Beware! There is a piece of flesh in the body if it becomes good (reformed) the whole body becomes good but if it gets spoilt the whole body gets spoilt and that is the heart

Arabic text (with chain of narrators)

حَدَّثَنَا أَبُو نُعَيْمٍ، حَدَّثَنَا زَكَرِيَّاءُ، عَنْ عَامِرٍ، قَالَ سَمِعْتُ النُّعْمَانَ بْنَ بَشِيرٍ، يَقُولُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏ "‏ الْحَلاَلُ بَيِّنٌ وَالْحَرَامُ بَيِّنٌ، وَبَيْنَهُمَا مُشَبَّهَاتٌ لاَ يَعْلَمُهَا كَثِيرٌ مِنَ النَّاسِ، فَمَنِ اتَّقَى الْمُشَبَّهَاتِ اسْتَبْرَأَ لِدِيِنِهِ وَعِرْضِهِ، وَمَنْ وَقَعَ فِي الشُّبُهَاتِ كَرَاعٍ يَرْعَى حَوْلَ الْحِمَى، يُوشِكُ أَنْ يُوَاقِعَهُ‏.‏ أَلاَ وَإِنَّ لِكُلِّ مَلِكٍ حِمًى، أَلاَ إِنَّ حِمَى اللَّهِ فِي أَرْضِهِ مَحَارِمُهُ، أَلاَ وَإِنَّ فِي الْجَسَدِ مُضْغَةً إِذَا صَلَحَتْ صَلَحَ الْجَسَدُ كُلُّهُ، وَإِذَا فَسَدَتْ فَسَدَ الْجَسَدُ كُلُّهُ‏.‏ أَلاَ وَهِيَ الْقَلْبُ ‏"‏‏.‏

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This is general information, not a fatwa. For your own situation, ask a qualified scholar.