Our Staff


John Barnett

John E. Barnett (President) has over thirty years of marketing and management experience in the construction, environmental and laboratory industries. Mr. Barnett joined QuanTEM 20 years ago and through diligent focus on growth has built QuanTEM into the premier testing laboratory it is today. His successes at QuanTEM include expansion of laboratory services to include most Indoor Environmental Quality concerns, promoting training courses for the education of environmental professionals, and insisting on excellent customer service throughout the organization. His varied experience includes hazardous materials site testing, assessment, and remediation, business ownership and executive level business management.

Dr. Yomi Ajibode, Technical Manager

Yomi Ajibode

Dr. Yomi Ajibode (Technical Manager) obtained her Ph.D. in microbiology from the University of Arizona. She has worked in both laboratory and industrial settings of the food industry. With her manufacturing plant experience, she has implemented HACCP, GMP and Sanitation programs in the meat industry.

Prior to joining team at QuanTEM Food Safety laboratories, she worked at Sadler’s Smokehouse in Henderson Texas in the Quality Assurance department, where she designed, developed, and maintained a successful environmental monitoring program, microbiological food testing program emphasizing test and hold procedures as well as microbiological independence between lots, verification of the sanitation program, allergen testing program and validation. She maintained safe quality foods from raw meat receiving to finished product shipment by monitoring the critical control points (CCPs) during process flow and product specifications. She also conducted sensory evaluation of finished products prior to shipment to ensure flavor and texture profile using a team of experienced panelists. As the HACCP coordinator she maintained safe quality foods through management of the rework program, ensuring quality inspections and pre-shipment requirements were met and deviations from process flow minimized. She also managed the internal chemistry (analyses of salt, phosphate, pH, degree of saltiness of meat, and meat tenderness using the Mark-10) and microbiology laboratory (environmental samples, air quality monitoring) and utilized the Pathogen Modeling Program (PMP) for meat and packaged meat using the USDA PMP software. She also started a monthly newsletter for the company as the staff editor, a medium she used to convey importance of food safety and quality to employees.

Prior to joining the team at Sadler’s, Dr. Yomi Ajibode worked at the Tyson foods laboratory in Waterloo, Iowa where she conducted analyses of lard, flotation grease by determining free fatty acid, peroxide value, moisture and volatile analysis of tallow, lard and grease. Microbiological analysis on raw and cooked meat, pet food as well as environmental samples using approved methods. She also taught lecture and laboratory classes for environmental microbiology, Introductory Biology for Allied Health and Introduction to Microbiology at Pima Community College in Tucson Arizona prior to joining the team at Tyson Foods.

Dr. Ajibode has certifications in HACCP and Safe Quality Foods (SQF) and has completed the Better Process Control School (BPCS) for thermally processed acidified and low acid foods.

Ingrid Gumbs-Diaz, Resource Development Specialist

Yomi Ajibode

Ingrid Gumbs-Diaz (Resource Development Specialist) joined QuanTEM in June of 2014. She has 12 years of experience in sales and marketing, as well as over 6 years of experience in laboratory bench work. She has a degree in Biochemistry from Oklahoma State University and a Master’s in Business Administration from Oklahoma City University. She is originally from San Juan, Puerto Rico. Her passion for science and business has put her in a position to establish beneficial and long lasting relationships with existing as well as potential clients wherever she goes. She has been in the soda industry, meat industry, as well as biochemistry and environmental quality lab service industry.

Ingrid brings to QuanTEM an approach of reinventing customer relationships, and innovation, making them a part of the QuanTEM family. Customers receive more than just lab results when working with her and the lab team. They enjoy a great partnership, a sincere concern for their business, and customized service to help them succeed.


Jeff Mledush

Jeff Mlekush (Vice President) has over fourteen years of experience in asbestos, lead, industrial hygiene and indoor air quality. He joined QuanTEM in March 2000. He has a Geology degree from the University of New Mexico and a Master of Business Administration from Oklahoma Christian University. Prior to joining QuanTEM Laboratories, Mr. Mlekush was the Senior Project Manager for Acme Environmental, Inc., an environmental training and consulting firm in Albuquerque, New Mexico. He was also the Asbestos/Industrial Hygiene Manager for Assaigai Analytical Laboratories, Inc., an analytical laboratory and industrial hygiene firm in New Mexico and Texas.


Steven Karr

Steven Karr (Accounting Manager) joined the QuanTEM team in May of 2012. He has a degree in accounting from the University of Central Oklahoma and is currently pursuing a Master's in Business Administration. Prior to coming to QuanTEM Steven has 20 years' experience in accounting and business operations.