Suspicious blood (fresh or dried) stains on cooked food and food utensils that may result from finger cuts, open sores, nose bleeds or handling of raw meat, poultry etc alongside cooked food can be detected easily using reliable and fast methods. These screening methods include sensitive preliminary and confirmatory chemical analysis for the possible presence of blood.

1. Kastle-Meyer Test: This is a preliminary test and can detect blood in dilutions of one part per 1,000. Phenolpthalin is reacted with 3% hydrogen peroxide and blood on a dampened swab. The color change on the swab from clear to pink-red is indicative of a positive result.

2. Teichman Test: This is a confirmatory test and is extremely specific for only blood and is done using a microscope. A chemical mix of potassium compounds in acetic acid is reacted with the blood stain on a slide and a cover-glass is applied to it. The slide is gently warmed until bubbles appear and is then allowed to cool slowly. If blood is present, deep brown crystals and rhomboids appear.

3. Luminol Test: This test detects trace amounts of blood. An alkaline solution of luminol is mixed with peroxide reagent just before the test. Blood on paper or fabric is sprayed with a 2% solution of hydrochloric acid. After 15 mins, the blood is sprayed with 5 % sodium carbonate followed by the luminol-peroxide reagent in a dark room. When blood is present, the smallest droplets emit a blue light. If the luminiscence fades,it may be reproduced by allowing the objects to dry and again spraying with luminol-peroxide reagent.