In the Old Testament, The Bible forbids Israelites to eat unclean creatures. Unclean animals are:-
Deu 14:7 Nevertheless these you shall not eat of them that chew the cud, or of those who have the hoof cloven: the camel, and the hare, and the rabbit; because they chew the cud but don't part the hoof, they are unclean to you.
Deu 14:8 The pig, because it has a split hoof but doesn't chew the cud, is unclean to you: of their flesh you shall not eat, and their carcasses you shall not touch.
Lev 11:27 Whatever goes on its paws, among all animals that go on all fours, they are unclean to you. Whoever touches their carcass shall be unclean until the evening.
Lev 11:29 " 'These are they which are unclean to you among the creeping things that creep on the earth: the weasel, the rat, any kind of great lizard,
Lev 11:30 the gecko, and the monitor lizard, the wall lizard, the skink, and the chameleon.
Lev 11:39 " 'If any animal, of which you may eat, dies; he who touches its carcass shall be unclean until the evening.
Lev 11:41 " 'Every creeping thing that creeps on the earth is an abomination. It shall not be eaten.
Lev 11:42 Whatever goes on its belly, and whatever goes on all fours, or whatever has many feet, even all creeping things that creep on the earth, them you shall not eat; for they are an abomination.
Also, they were not to eat of animals that they normally would have been able to eat if they had died by themselves or been killed by other animals:-
Lev 22:8 That which dies of itself, or is torn by animals, he shall not eat, defiling himself by it. I am Yahweh.
HOWEVER, ALL of this about clean and unclean animals is changed in the New Testament.
The Apostle Peter (who really knew the [Old Testament] scriptures) had received a vision showing him both clean and unclean creatures, and he didn't know what it meant:-
Act 10:9 On the morrow, as they went on their journey, and drew nigh unto the city, Peter went up upon the housetop to pray about the sixth hour:
Act 10:10 And he became very hungry, and would have eaten: but while they made ready, he fell into a trance,
Act 10:11 And saw heaven opened, and a certain vessel descending unto him, as it had been a great sheet knit at the four corners, and let down to the earth: Act 10:12 Wherein were all manner of fourfooted beasts of the earth, and wild beasts, and creeping things, and fowls of the air.
Act 10:13 And there came a voice to him, Rise, Peter; kill, and eat.
Act 10:14 But Peter said, Not so, Lord; for I have never eaten any thing that is common or unclean.
Act 10:15 And the voice spake unto him again the second time, What God hath cleansed, that call not thou common.
Act 10:16 This was done thrice: and the vessel was received up again into heaven.
Act 10:17 Now while Peter doubted in himself what this vision which he had seen should mean, behold, the men which were sent from Cornelius had made enquiry for Simon's house, and stood before the gate,
Act 10:18 And called, and asked whether Simon, which was surnamed Peter, were lodged there.
Note especially verses 14 and 15: God tells Peter unclean animals were now clean.
Another translation makes this distinction a little clearer:-
Act 10:14 But Peter said, "Certainly not, Lord, for I have never eaten anything defiled and ritually unclean!"
Act 10:15 The voice spoke to him again, a second time, "What God has made clean, you must not consider ritually unclean!" (NET Bible)
This vision Peter saw was from God:-
Act 10:19 While Peter thought on the vision, the Spirit said unto him, Behold, three men seek thee.
Act 10:21 Then Peter went down to the men which were sent unto him from Cornelius; and said, Behold, I am he whom ye seek: what is the cause wherefore ye are come?
Act 10:22 And they said, Cornelius the centurion [he was a gentile] a just man, and one that feareth God, and of good report among all the nation of the Jews, was warned from God by an holy angel to send for thee into his house, and to hear words of thee.
Act 10:28 And he[Peter] said unto them, Ye know how that it is an unlawful thing for a man that is a Jew to keep company, or come unto one of another nation; but God hath shewed me that I should not call any man common or unclean.
Act 10:29 Therefore came I unto you without gainsaying, as soon as I was sent for: I ask therefore for what intent ye have sent for me?
Act 10:30 And Cornelius said, Four days ago I was fasting until this hour; and at the ninth hour I prayed in my house, and, behold, a man stood before me in bright clothing,
Act 10:31 And said, Cornelius, thy prayer is heard, and thine alms are had in remembrance in the sight of God.
Act 10:32 Send therefore to Joppa, and call hither Simon, whose surname is Peter; he is lodged in the house of one Simon a tanner by the sea side: who, when he cometh, shall speak unto thee.
Act 10:33 Immediately therefore I sent to thee; and thou hast well done that thou art come. Now therefore are we all here present before God, to hear all things that are commanded thee of God.
Act 10:34 Then Peter opened his mouth, and said, Of a truth I perceive that God is no respecter of persons:
Act 10:35 But in every nation he that feareth him, and worketh righteousness, is accepted with him.
The Jews were God's people, they were a Godly nation, and therefore everything else was not Godly: they were 'clean' and everybody else were 'unclean'.
God was telling Peter that just as there was now to be no clean and unclean foods, so there were to be no clean and unclean peoples: there was to be no distinction between Jew and Gentile - they were all the same to God:-
Rom 14:1 Now receive the one who is weak in the faith, and do not have disputes over differing opinions.
Rom 14:2 One person believes in eating everything, but the weak person eats only vegetables.
Rom 14:3 The one who eats everything must not despise the one who does not, and the one who abstains must not judge the one who eats everything, for God has accepted him.
Rom 14:4 Who are you to pass judgment on another's servant? Before his own master he stands or falls. And he will stand, for the Lord is able to make him stand.
Rom 14:5 One person regards one day holier than other days, and another regards them all alike. Each must be fully convinced in his own mind.
Rom 14:6 The one who observes the day does it for the Lord. The one who eats, eats for the Lord because he gives thanks to God, and the one who abstains from eating abstains for the Lord, and he gives thanks to God.
Rom 14:7 For none of us lives for himself and none dies for himself.
Rom 14:8 If we live, we live for the Lord; if we die, we die for the Lord. Therefore, whether we live or die, we are the Lord's.
Rom 14:9 For this reason Christ died and returned to life, so that he may be the Lord of both the dead and the living.
Rom 14:10 But you who eat vegetables only - why do you judge your brother or sister? And you who eat everything - why do you despise your brother or sister? For we will all stand before the judgment seat of God.
Rom 14:11 For it is written, "As I live, says the Lord, every knee will bow to me, and every tongue will give praise to God."
Rom 14:12 Therefore, each of us will give an account of himself to God.
(What had happened was that some were saying they were holier than someone else because they obeyed the distinction between clean and unclean meats).
Col 2:16 Let no man therefore judge you in meat, or in drink, or in respect of an holyday, or of the new moon, or of the sabbath days:
Col 2:17 Which are a shadow of things to come; but the body is of Christ.
In the Old Testament people were restricted to eating clean foods only because the ordinances were physical: in the New testament the ordinances were spiritual, so the obligatory physical restrictions were removed and instead made voluntary, so it was now permissible to eat anything including unclean foods .
It is the intent that is important: no distinction need now apply between clean and unclean foods; however, for health reasons it is better to eat clean rather than unclean foods.
Actually, nothing is changed in the New Testament! Using these verses in Acts to try and show that all food is now clean is a direct contradiction of Deuteronomy 12:32 and Proverbs 30:5-6, just to name a couple. It is very clear that God does not want us to add to or take away from His Word.
Without looking at the context of this story it is easy for one to assume that all food is now clean, but there are a couple of problems with this understanding.
First is that it implies that God changed his mind, but Malachi 3:6 tells us that He NEVER changes. That means if he says he doesn't want us to eat these animals because they are unclean, then he is not going to change His mind one day and change that. To say that He did away with our requirement to abstain from unclean animals is to say that He CHANGED, and we know that HE never changes.
Secondly, to interpret what ones wants to believe from Peter's vision would be adding to the Word and we know that adding to His Word is a violation and we are not permitted to do so. Two times Peter told the story of his vision and what it meant and neither time did he mention anything about food. For anyone to assume that this is the case makes them guilty of adding to the Word. I find it hard to believe that if this vision was in fact about eating clean and unclean animals that Peter would have mention something about food when he was telling people "HIS interpretation of HIS vision". God was using these animals as an example to show Peter that Gentiles were not unclean people.
At the time when Peter had this vision, Jews were forbidden from even entering the house of a Gentile. This was not a commandment of God, but was a man made law put in place by the Priest of the day. God was showing Peter that no man was unclean because He made all of us, not just the Jewish People.
It's very important to study scripture in the context of time and culture. These verses were written 1000's of years ago and we need to think about what they meant to their original audience FIRST, before we apply them to our 21st century mindset and lifestyles. That is the only way to get the context of what is being said and without context it is nearly impossible to ever truly understand the message that the Bible is trying to teach us.
There are no animals that all humans are commanded not to eat. The list of kosher animals and fish (Deuteronomy ch.14), and the list of non-kosher birds (ibid.), were commanded upon the Israelites only, not other nations.