Fluorescence in situ hybridization (FISH) is a cytogenetic technique used to detect and localise the presence of
specific DNA sequences11. In situ hybridization (ISH) was initially and independently developed by Pardue and
Gall12 and by John et al.13 within the context of intact cytological preparation. The DNA probes were radiolabelled
and the detection was carried out by autoradiography. In the FISH procedure, radioactivity was replaced
with fluorescence14. FISH protocols are now based on the specific hybridization of a fluorescently labelled probe
with its complementary target sequence15. Hybrids formed between the probes and their DNA targets are detected
using fluorescence microscopy.
FISH is widely used for several applications in clinical diagnosis and research16, as well as for the detection and
localisation of genomic aberrations, gene mapping17, the localisation of gene expression18 and microbiological
diagnosis15. Microbiological diagnosis is used in food safety to detect microbial contaminants19.
The study reported in this paper proposes a new detection method for feed analysis based on the specificity and
flexibility of DNA labelling combined with the sensitivity of microscopy. It describes the development of fluorescently
labelled probes for the specific identification of bovine and ruminant bones and an original FISH
protocol adapted for bone particles that have not undergone the usual demineralisation step. The study also