A spectroscopy-based proof-of-concept (POC) for developing loading of pathogen analyzer (LOPA) for dairy products
Lopamudra Roy,
Amrita Banerjee,
Nivedita Pan,
Ria Ghosh,
Susmita Mondal,
Monojit Das,
Md Nur Hasan,
Soumendra Singh,
Arpita Chattopadhyay,
Kallol Bhattacharyya,
Soumen Mondal,
Samir Kumar Pal
Affiliations
Lopamudra Roy
Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India; University of Calcutta, Department of Applied Optics and Photonics, JD-2, Sector-III, Salt Lake, Kolkata, West Bengal, 700 106, India
Amrita Banerjee
Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India; Department of Physics, Jadavpur University, 188, Raja Subodh Chandra Mallick Rd, Poddar Nagar, Jadavpur, Kolkata, West Bengal, 700032, India
Nivedita Pan
Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India
Ria Ghosh
Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India
Susmita Mondal
Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India
Monojit Das
Department of Zoology, Vidyasagar University, Rangamati, Midnapore, 721102, India; Department of Zoology, Uluberia College, University of Calcutta, Uluberia, Howrah, 711315, India
Md Nur Hasan
Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India
Department of Basic Science and Humanities, Techno International New Town Block, DG 1/1, Action Area 1 New Town, Rajarhat, Kolkata, 700156, India
Kallol Bhattacharyya
University of Calcutta, Department of Applied Optics and Photonics, JD-2, Sector-III, Salt Lake, Kolkata, West Bengal, 700 106, India
Soumen Mondal
Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India; Corresponding author.
Samir Kumar Pal
Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India; Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India; Corresponding author. Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Kolkata, 700106, India.
Detection of bacterial contamination in dairy products of daily use is a challenge worldwide. We have utilized Methylene Blue Reduction Test (MBRT) for quantification of the microbial count in dairy products (milk) and developed a proof-of-concept (POC) based on this for in-filed applications. In this study, we have used pasteurized milk contaminated with model bacteria Escherichia coli, and Staphylococcus aureus for the calibration and validation of the developed POC. The conversion of MB to Leuco-MB i.e., the colorimetric change due to the reduction of MB to Leuco-MB in presence of microbes has been utilized as the tool to detect presence of microbes in milk. The absorbance peak for methylene blue (MB) at 664 nm decreases significantly in presence of microbes and the blue color becomes faded. In our study, we have employed methylene blue (MB) discolouration phenomenon to estimate the microbial count in milk samples using our developed spectroscopy based POC. The limit of detection (LOD) and the limit of quantitation (LOQ) of the POC were found to be 0.32 CFU/mL and 0.97 CFU/mL. The end users of the developed POC are primarily those involved in the production, processing, testing, regulation, and research of dairy products to ensure they meet safety standards and protect public health. These include retailers, dairy farmers, dairy processors, quality control laboratories, regulatory agencies and research institutions. In our experiment, we have observed a significant change in MB absorption in the milk contaminated with microbes. The indigenously developed sensor strips designed for the working of the POC turn to colorless Leuco-MB compared to milk without the microbes. The analysis of the strips has been measured in the developed device.
