J. David Legan, PhD
Director of Science
David earned his Ph.D. in Food Technology from the University of Reading in the UK by modeling the ecology of mixed microbial populations, and then moved to Campden BRI in a variety of microbiological food safety research and client service roles. During that time, he was project lead for the Bacillus component of the UK’s pathogen modeling program. He moved again to Nabisco Research in New Jersey where he ran the corporate microbiology lab and developed a program of preservation technology development and microbial modeling. After the Kraft Foods acquisition, he moved to Chicago to work on Food Safety and Preservation research, and through modeling and validation studies:
- Optimized Oscar Mayer’s use of lactate and diacetate and their naturally cultured alternatives as Listeria-control agents in Ready to Eat meats
- Specified process conditions central to Oscar Mayer’s commercial launch of High Pressure Pasteurization of naturally cured RTE meats
David had responsibility for the Kraft cultures R&D group, developed a partnership to explore microwave sterilization leading to several patents, and led a program that developed an internal proprietary natural antimicrobial commercialized in several Kraft products. Technologies from his group supported approximately $4 billion in annual sales.
After years as a microbiology "client", he is now back in the "provider" role as Director of Science at Eurofins Microbiology Laboratories, Inc., by way of the Covance Food Solutions group based in Madison, WI, which he joined in 2016. In this role, he ensures appropriate method validation, explores new testing technologies, and fields multiple complicated food microbiology questions.
Products that his team has evaluated or developed and launched include:
- The 3M MDS platform in the Madison microbiology laboratory
- Flow cytometry for enumeration of probiotics
- Strain-level confirmation of probiotic identification using the polymerase chain reaction (PCR)
- Next-generation sequencing using the Oxford Nanopore Technologies GridION sequencing platform for microbial identification and microbiome analysis
Below are resources from David:
This article describes the basics of flow cytometry in its application to probiotic enumeration, including a comparison between flow cytometry and traditional plate count methods, afu vs cfu, advantages and disadvantages of flow cytometry, marketplace examples and investigative case studies.
Andrzej Benkowski, Technical Manager, Eurofins Microbiology Laboratories Inc, is one of the authors of this article from Frontiers in Microbiology, discussing enumeration techniques for probiotic and postbiotic analytical methods.
This poster discusses research with the purpose of demonstrating a proof of concept for a reliable methodology evaluating postbiotic materials as characterized by inanimate cells by flow cytometry.
In a recent webinar, experts answered some FAQs about probiotic enumeration, with a focus on the applications of flow cytometry to probiotic products. This blog provides an overview of the questions and answers, including the benefits of flow cytometry, how it compares to plate counts, and considerations for testing.
This is a follow up on our very successful previous webinar session where we discussed what is flow cytometry, advantages and disadvantages of flow cytometry, and marketplace examples and investigative case studies. Original airdate August 8, 2023.
Flow cytometry provides rapid, accurate, and powerful results for probiotic brands and manufactures. This case study demonstrates how flow cytometry can assist with low-cell count investigations by reveling the number of live, injured, and dead cells.
Probiotic enumeration is a key component of a probiotic testing scheme. Traditional plate count methods can provide inaccurate results, especially considering non-culturable cells. This case study demonstrates how flow cytometry can determine an accurate cell count, even of non-culturable, live cells.
Combining multiple strains of bacteria in a single probiotic product is a popular way to increase its health benefits. Flow cytometry provides a method for enumerating individual strains or species with accurate total bacteria counts. This case study demonstrates how flow cytometry can assist with multi-species enumeration when plate count methods provide low counts.
Microencapsulated cells provide a way to introduce probiotics into new products, like drinks. However, plating methods often fail to recover live cells in this form. Flow cytometry provides rapid, accurate, and powerful results for the enumeration of microencapsulated probiotics. This case study demonstrates how flow cytometry can assist with microencapsulated enumeration in a drink product.
Postbiotics are increasing in popularity, but are difficult to enumerate with traditional plating methods. Flow cytometry provides an avenue for measuring the dead or inactive cells in postbiotic products. This case study demonstrates how flow cytometry can assist with postbiotic enumeration when plate methods result in low cell counts.
