Foods produced in
      the West, such as gelatin
Question

                For a great time now my community and I have been concerned with the issue of foods such as Gelatin, mono and dyglycerides, pepsin and rennetAll these thing are in our foods today and yet we do not know what we can eat and the reason for each. PLease give me a very detailed response that could end this trouble.
Praise be to Allah.Allaah
      has blessed His slaves by creating for them all kinds of provision on
      earth, and He has permitted them to eat from that which is halaal
      (permissible) and good; this includes very many things, it is not limited.
      Allaah says (interpretation of the meaning):
“O mankind! Eat of that which is lawful and good on the earth, and follow
      not the footsteps of Shaytaan (Satan). Verily, he is to you an open
      enemy.” [al-Baqarah 2:168]
Allaah
      forbids a limited number of foods, as He says (interpretation of the
      meaning):
“Say (O Muhammad): “I find not in that which has
      been revealed to me anything forbidden to be eaten by one who wishes to
      eat it, unless it be Maitah (a dead animal) or blood poured forth (by
      slaughtering or the like), or the flesh of swine (pork); for that surely,
      is impure or impious (unlawful) meat (of an animal) which is slaughtered
      as a sacrifice for others than Allaah (or has been slaughtered for idols,
      or on which Allaah’s Name has not been mentioned while slaughtering).”
      [al-An’aam 6:145]
 The
      Prophet 
 (peace and blessings of Allaah be upon him) forbade the
      eating of every carnivorous animal that has fangs, and every bird which
      has talons. (Narrated
      by Muslim, 6/60)
 And
      he forbade the flesh of (domestic) donkeys (narrated
      by al-Mukhari in al-Fath, no. 4215).
 Of
      the foods which are to be found nowadays, some of them are clearly haraam,
      such as dead meat [from an animal which has died naturally as opposed to
      being slaughtered properly] and pork. Some foods may contain ingredients
      and derivatives which come from haraam sources, so we have to find out
      where they come from so that we may know what the ruling is concerning
      them. The gelatin which was mentioned in the question may originate from
      the skin, muscles and bones of haraam animals such as pigs. Hence gelatin
      which is derived from collagen which comes from pigs is haraam, because it
      is as if the pig had been turned into salt. The most correct view is that
      it is haraam even if it has been changed, so long as it originally came
      from a pig, which is haraam.
 The
      fats which are used in foods come either from vegetable sources or animal
      sources.
 If
      they come from vegetable sources they are halaal, so long as they have not
      been mixed with anything that is impure (najjis) or anything that could
      contaminate them. If they come from animal sources, they are either from
      animals that we are permitted to eat or animals that we are not permitted
      to eat. 
If
      they come from an animal that we are permitted to eat, then they come
      under the same ruling as the meat of that animal. 
If
      they come from an animal which it is haraam for us to eat – such as pigs
      – then we look at whether they are used in foods or for other purposes. 
If
      they are usedfor non-food
      purposes, e.g. many fats are used in making soap, then there is a
      difference of scholarly opinion, but the most correct view is that they
      are haraam. 
If
      they are used in foods, e.g., pig fat (lard) is used in making sweets and
      other foods, this is haraam. 
With
      regard to cheese: if it is made from the milk of an animal which we are
      not permitted to eat, then according to scholarly consensus it is not
      permissible to eat it. If it is made from the milk of an animal which we
      are permitted to eat, and it is known that it is made with rennet that has
      been derived from an animal slaughtered according to sharee’ah andit has not been mixed with any najaasah (impurity), then it may be
      eaten. 
If
      it was made with rennet derived from dead meat, there is a difference of
      scholarly opinion as to whether we may eat it, but the most correct view
      is that it is haraam. 
If
      it was made with rennet from a source which is inherently naajis (impure),
      such as rennet derived from pigs, then it should not be eaten. 
See
      Ahkaam al-At’imah fi’l-Sharee’ah al-Islamiyyah by al-Tareeqi,
      p. 482 
In
      many cases these matters are unclear to the Muslim (he does not know the
      source of food ingredients). In this case, it is better to fear Allaah and
      be cautious. Avoiding doubtful things may be preferable to using them in
      these circumstances, as stated in the hadeeth narrated by al-Nu’maan ibn
      Basheer (may Allaah be pleased with him) who said: I heard the Messenger
      of Allaah 
 (peace and blessings of Allaah be upon him) say – and
      al-Nu’maan pointed to hisears
      – “That which is lawful is plain and that which is unlawful is plain,
      and between the two of them there are doubtful matters about which not
      many people know. Thus he who avoids doubtful matters clears himself in
      regard to his religion and his honour, but he who falls into doubtful
      matters falls into that which is unlawful, like the shepherd who pastures
      around a sanctuary, all but grazing therein. Truly every king has a
      sanctuary, and truly Allaah’s sanctuary is His prohibitions. Truly in
      the body there is a morsel of flesh which, if it is sound, all the body issound and which, if it is corrupt, all of it will be corrupt. Truly
      it is the heart.”
(Narrated
      by Muslim, 1599).
From
      the above we learn that the basic principle concerning food is that it is
      halaal, apart from those things for which there is clear evidence (daleel)
      that they are haraam, such as dead meat, blood, animals sacrificed to
      other than Allaah and meat over which the name of Allaah was not
      pronounced at the time of slaughter. Concerning the foods mentioned in the
      question: if it is proven that they contain ingredients derived from
      haraam sources, it is necessary to avoid them, otherwise they need not be
      avoided. If you are not sure whether they contain anything haraam or not
      – without being paranoid or succumbing to the waswaas (insinuating
      whispers of the Shaytaan) – then it is preferable to avoid them as a
      precaution out of fear of Allaah.
And
      Allaah knows best.