The identification of an accidental introduction may be based upon the type of foreign matter involved (e.g., an insect likely to be living amongst the field crop before harvest), or knowledge of the food processing involved (e.g., presence of burnt food material). The identification of deliberate contamination is much more specific, but could involve, for example, evidence of tampering with the packaging. The judgement as to whether there is strong evidence that foreign matter has been introduced accidentally or deliberately is made by the examining laboratory based on history of the incident and laboratory analysis.