Chemical test for mammalian feces in grain products: collaborative study

Area of Science:

• Food Science
• Analytical Chemistry
• Microbiology

Background:

• Mammalian feces contamination in grain products poses a food safety risk.
• Accurate detection methods are crucial for ensuring the safety and quality of grain-based foods.
• Existing methods may require validation for broader application across diverse grain products.

Purpose of the Study:

• To validate the AOAC alkaline phosphatase method for detecting mammalian feces in seven additional grain products.
• To assess the method's efficacy and reliability beyond its initial application in corn meal.
• To provide a validated analytical procedure for improved food safety in the cereal industry.

Main Methods:

• Utilized the AOAC alkaline phosphatase method employing phenolphthalein diphosphate as a substrate.
• Separated fecal matter from grain products based on specific gravity differences in 1% test agar.
• Visualized fecal presence through the generation of a pink to red-purple color upon enzymatic activity.

Main Results:

• Collaborators achieved recovery averages ranging from 72.3% (oat bran) to 84.3% (semolina) at a 30-particle spike level.
• The method demonstrated a low average background of 0.4 positive reactions per food type.
• The method was reported as quick, simple, and easy to use by collaborators.

Conclusions:

• The alkaline phosphatase method is effective for detecting mammalian feces in brown rice cream, oat bran, grits, semolina, pasta flour, farina, and barley plus.
• The method's ease of use and speed make it suitable for routine food safety testing.
• The method has been approved interim official first action for the tested grain products, enhancing food safety protocols.