✅ Answer: This question is clarified by the following two principles:

1⃣مُحَمَّدُ بْنُ یَعْقُوبَ عَنْ مُحَمَّدِ بْنِ یَحْیَی عَنْ مُحَمَّدِ بْنِ الْحُسَیْنِ عَنْ عَلِیِّ بْنِ الْحَکَمِ عَنِ الْعَلَاءِ بْنِ رَزِینٍ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ عَنْ أَحَدِهِمَا أَنَّهُ سُئِلَ عَنِ الطَّعَامِ یُخْلَطُ بَعْضُهُ بِبَعْضٍ وَ بَعْضُهُ أَجْوَدُ مِنْ بَعْضٍ قَالَ إِذَا رُئِیَا جَمِیعاً فَلَا بَأْسَ مَا لَمْ یُغَطِّ الْجَیِّدُ الرَّدِی ءَ

Translation: Muhammad ibn Muslim narrated from one of the two Imams, Imam Baqir or Imam Sadiq (peace be upon them), that when asked about food (legumes) being mixed, where one type is superior to the other, the Imam replied: If both are visible, there is no problem, as long as the good quality does not cover the inferior quality.

📚 Al-Kafi, Vol. 5, p. 183

Translation: Halabi narrated that I asked Imam Sadiq (peace be upon him) about a person who has two types of food with different prices, one of which is better than the other. He mixes both and sells them at one price. The Imam replied: It is not appropriate to do so and deceive the Muslims unless he informs the buyer (discloses the truth to the buyer).

2⃣عَنْ عَلِیِّ بْنِ إِبْرَاهِیمَ عَنْ أَبِیهِ عَنِ ابْنِ أَبِی عُمَیْرٍ عَنْ حَمَّادٍ عَنِ الْحَلَبِیِّ عَنْ أَبِی عَبْدِ اللَّهِ قَالَ سَأَلْتُهُ عَنِ الرَّجُلِ یَکُونُ عِنْدَهُ لَوْنَانِ مِنْ طَعَامٍ وَاحِدٍ سَعَّرَهُمَا شتی وَ أَحَدُهُمَا أَجْوَدُ مِنَ الْآخَرِ فَیَخْلِطُهُمَا جَمِیعاً ثُمَّ یَبِیعُهُمَا بِسِعْرٍ وَاحِدٍ فَقَالَ لَا یَصْلُحُ لَهُ أَنْ یفعل ذلک یَغُشَّ به الْمُسْلِمِینَ حَتَّی یُبَیِّنَهُ

📚 Al-Tahdhib, Vol. 7, p. 34

Explanation: Based on the two narrations above, if, for example, high-quality and low-quality rice are mixed and both are fully visible and distinguishable, or if the seller informs the buyer, there is no issue. Otherwise, it would be considered deceit (cheating and fraud).

اللَّهُمَّ فَصَلِّ عَلَی مُحَمَّدٍ وَ آلِ مُحَمَّدٍ وَ عَجِّلْ لِوَلِیِّکَ الْفَرَجَ وَ الْعَافِیَةَ وَ النَّصْرَ