A recent technique for the detection of Bacillus cereus in milk

Elgushi, Ahmed Mohammed; Mohammed, Hamdi Abdelsamei; Elbarbary, Hend Ahmed; Elmasry, Dalia Mohammed; El-Husseini, Dalia Mostafa

doi:10.21608/ejchem.2023.228683.8411

A recent technique for the detection of Bacillus cereus in milk

Document Type : Original Article

Authors

¹ Biotechnology Department, Animal Health Research Institute, Agriculture Research Center, Dokki, Egypt.

² Food Hygiene and Control Department, Faculty of Veterinary Medicine, Benha University, Egypt.

³ Nanomaterials Research and Synthesis Unit, Animal Health Research Institute, Agriculture Research Center, Dokki, Egypt.

⁴ Nanomaterials Research and Synthesis Unit, Animal Health Research Institute, Agriculture Research Center, Dokki, Egypt

10.21608/ejchem.2023.228683.8411

Abstract

The occurrence of Bacillus cereus in milk and dairy products is attributed to deficient hygiene protocols, consequently resulting in two gastrointestinal illnesses: rare emetic sickness and diarrheal illness triggered by enterotoxins. The current study aimed to overcome the limitations of PCR in detecting low bacterial concentrations through the incorporation of unmodified gold nanoparticles (GNPs) in PCR. Bacillus cereus in milk was analyzed using the GNPs-assisted PCR method to detect the Nhe A gene in comparison to conventional PCR and Sybergreen qPCR. The NheA gene is a key virulence factor that encodes a protein involved in the generation of non-hemolytic enterotoxins. The result showed adding GNPs to PCR reactions boosted DNA yields and enabled detection down to 102 copies of Bacillus cereus DNA, versus 103 with standard PCR. GNP-PCR detected Bacillus cereus for spiked milk samples at 102 CFU/ml, while conventional PCR required 103 CFU/ml. Sybrgreen qPCR also achieved detection at 102 copies and 102 CFU/ml for spiked milk. GNP-PCR specifically amplified Bacillus cereus, not other bacteria like Bacillus subtilis, E. coli, Staphylococcus aureus, Listeria monocytogenes, and Salmonella, demonstrating assay specificity. Overall, GNPs improved PCR sensitivity for Bacillus cereus detection.

Keywords