When somebody mentions terrorism attack the attention is immediately concentrated on military type attacks such as bombs, kamikazes or similar kinds and nobody thinks about the possible existence of more sophisticated means such as the use of toxic gas or agents which may be transmitted by contaminated food, water and air and may interest a large number of people. This book intends to put the attention on this problem and to demonstrate how easy it is in particular to contaminate food. Four different sectors were analysed: bacteria, virus, parasites and pollutants and for each the possible agents and the facilities for creating diseases in many people through contaminated food are described. Also some species of common bacteria like Escherichia coli or Enterococci, present in many foods, may produce toxins, causing diarrhoea in a large number of persons as happened in China in 1991 when 224,000 persons were affected by contaminated ice cream. On the other hand parasites can also be transmitted by uncooked fish and reptile meat. New diagnostic methods are also illustrated which in comparison to traditional methods permits quick analysis of many samples.