Surah No. 5, Al Maaeda, Ayat No. 5
الْيَوْمَ أُحِلَّ لَكُمُ الطَّيِّبَاتُ وَطَعَامُ الَّذِينَ أُوتُواْ الْكِتَابَ حِلٌّ لَّكُمْ وَطَعَامُكُمْ حِلُّ لَّهُمْ
وَالْمُحْصَنَاتُ مِنَ الْمُؤْمِنَاتِ وَالْمُحْصَنَاتُ مِنَ الَّذِينَ أُوتُواْ الْكِتَابَ مِن قَبْلِكُمْ إِذَا
آتَيْتُمُوهُنَّ أُجُورَهُنَّ مُحْصِنِينَ غَيْرَ مُسَافِحِينَ وَلاَ مُتَّخِذِي أَخْدَانٍ وَمَن يَكْفُرْ بِالإِيمَانِ
O فَقَدْ حَبِطَ عَمَلُهُ وَهُوَ فِي الآخِرَةِ مِنَ الْخَاسِرِينَ
This day good things are made lawful for you. The food of those who have received the Scripture is lawful for you, and your food is lawful for them. And lawful are the pure women of the believers and the pure women of those who received the Scripture before you, when you give them their bridal money (Mehr) and live with them in honour, not to seek only pleasure , nor taking them as secret companions. Who rejects the faith, all his work will go in vain and he will be the loser in the Hereafter.
In the past ,we were allowed to marry pure girls of those people who were given Scriptures (Holy Books). In present circumstances, the Jews and Christians, though they are the possessors of the holy books but they have totally ignored the guidelines and started eating flesh of swine, started drinking alcohol and left the purity. Therefore marriage of a believer with their girls is not good so also marriage of Muslim girl with their boys should also be avoided, as there is danger of losing faith of boys and girls of the believers. ( Tafsir of Maulana Abdul Karim Parekh " Tashrihul Quran 5:5 ). Food of such people should also be avoided as there is a 100% possibility of contamination of Pork and Wine in their food articles.