Blood meal and blood products detection using Synchronous fluorescence spectroscopy

In Europe, ruminant processed animal proteins (PAPs) and blood products are not allowed to be used in feed for farmed animal. In contrast, blood meal and blood products of porcine origin are both authorised in aqua feed, whereas only porcine blood products are allowed to be used in feed intended for other non-ruminants.
Besides official methods (light microscopy and PCR), complementary methods are developed in order to refine the by-products identification. By-products derived from blood are one of these products for which additional information are needed. Indeed, these prohibited materials sometimes cannot be distinguished from those authorised (e.g. milk powder) using official methods.
The aim of this work was to develop a fast and easy method to detect blood meal and blood products. This study was based on the detection of hemoglobin in animal feed by synchronous fluorescence spectroscopy (SFS).
To achieve this goal, preliminary tests were carried out on reference material (hemoglobin and albumin purchased from Sigma Aldrich) in order to determine appropriate conditions (solvent) and parameters (offset values) for hemoglobin detection. Selected settings were then applied to analyse protein extracts of commercial feed material derived from blood. The results obtained on blood meal and blood products (hemoglobin powder and plasma powder) showed fluorescence spectral bands that characterise hemoglobin. In order to determine whether the method was fit for the purpose, real commercial compound feeds known to contain or to be free from blood products or blood meal were analysed. The Principal Component Analysis (PCA) applied to these spectra showed that it was possible to discriminate samples containing hemoglobin from those that do not contain. This result confirmed that SFS is a promising screening method for the detection of hemoglobin in animal feed.