Microbiological quality assessment of the poultry broiler starter feed

The poultry feed industry has grown as a large-scale industry in Sri Lanka. Amidst the growth in the industry, producing high quality and safety feed is important. Biological contaminants; bacteria and fungi are the key causes for feed deterioration, and diseases in poultry. Thus, this study aimed to investigate the microbiological quality of 32 broiler starter feed samples, considered to one feed brand, collected from eight feed distributors and their 24 feed-supplying farms in Kurunegala district. The samples were processed for detection of Enterobacteriaceae (ENT) count, aerobic plate count (APC), and Salmonella spp as per the ISO and SLS guidelines. Lacto Phenol Cotton Blue (LPCP) staining was performed to identify the fungi species. According to the EU safety levels, the ENT, APC, and moulds of poultry feed should be present below 300 cfu/g, 1.0×10⁶ cfu/g, and 1.0×10⁶ CFU/g respectively, and Salmonella should be absent as per both EU and ISO standards. The ENT of one sample at the distributor stage exceeded 300 CFU/g. None of the samples were positive for Salmonella. The APC varied between 4.3×10³ and 1.9×10⁵ CFU/g, giving the mean APC of 6.4×10⁴ CFU/g and 1.3×10⁵ CFU/g at distributor and farm levels. Aspergillus spp, Penicillium spp, and Rhizopus spp were identified from the cultured feed at the distributor stage and the count varied between 1.0×10² and 3.0x10² CFU/g whereas Mucor, Cladosporium spp, and Scopulariopsis spp, were additionally identified from farm level feed samples, and count varied between 1.0×10² and 2.1×10³ CFU/g. The TBC and the fungi count were significantly different (P< 0.0001 and P=0.01) at the farm stage. Although the TBC and the fungi count at the farm stage are within the safety levels, there is suggestive biological contamination. Further, the diversity of the moulds present in the feed samples indicates the environmental contamination of the processed feed.