About Us
Our Team is a select group of experienced chemists and professionals 
that hold themselves and others to the highest quality and scientific standards. 
Our staff comes with extensive backgrounds working at both other cannabis labs
 and across many other scientific industries. 
Pacific Star Labs takes pride in only hiring the most competent team members,
providing first-class training, and professional development opportunities. 
By valuing quality over quantity, 
Pacific Star Labs offers not only premier lab testing services, 
but also exceptional customer service above-and-beyond the industry norm.

Our Team
David Winternheimer, PhD, PPM -- General Manager

David has founded and advised more than 8 start-ups over the past decade in business development leadership positions, enabling many of them to achieve profitability and/or exit opportunities in their first years of operation. In addition to deep experience in sales/marketing, he also provides technical expertise to the team. David received his PhD in organic chemistry from UCLA and his Postdoctoral Professional Masters in Bioscience Management (PPM) from the Keck Graduate Institute of Applied Life Sciences.

Sam Alcantar, BS -- Lab Director

Sam was one of the early scientists at one of the first cannabis testing labs in California, and has experience operating or advising additional cannabis labs with all California-mandated analytical chemistry assays. With over 5 years of experience testing cannabis, he is a true expert in the field. Sam received his BS in chemistry from UCSB where he contributed to publications on thin films and nano-electronics.

James Borgese, BS -- Lead Scientist

James is one of the first chemists to have worked in heavy metal (ICP-MS) analysis in cannabis. As lead scientist, he is responsible for much of Pacific Star Labs’ method development/validation and continues to contribute to method optimization. James attended UC Berkeley and received his BS in chemical engineering from CSU Long Beach.

Sheryl Silverman, BS -- Microbiology & Quality Managers

Sheryl has over a decade of experience in research using PCR with a background in molecular genetics. She also has over 5 years of experience in managing ISO quality systems. As both microbiology and quality managers, she oversees microbial contamination testing and the full quality management system. Sheryl received her BA in chemistry with a minor in biology from Arcadia University. 

Tommie Griffin, BS -- Chemist I

Tommie has an extensive background in cannabis (both in-field cultivation and lab testing) with experience validating and operating cannabis testing procedures in both Northern and Southern California. Tommie is cross-trained on all analytical methods at Pacific Star Labs. He received his BS in Biochemistry from Humboldt State University.

Lucia Hernandez, BS -- Lab Assistant

Lucia is well versed in ISO 17025 processes through her tenure working at Eurofins, a leading environmental testing lab in the USA. She supports the team from sample accession through analytical batch preparation. She received her BS in biology from CSULA.
RJ Fenske -- Director of Marketing

RJ is an engagement specialist focused on people’s core needs, emotions and behavioral decisions. He brings an extensive background in digital media marketing and strategic development to improve user engagement across all mediums. He builds and nurtures the complex cross-functional groups through an ever evolving digital landscape. With a diverse background ranging from the entertainment industry, big pharma, biotech startups and health & wellness. He is devoted to enhancing global collaboration to empower better user experiences and accelerate the development of products that serve people's true needs.

Pacific Star Labs

621 W Rosecrans Ave, Suite #104
Gardena, CA  90248

(310) 538-2094

About Us
Our Team is a select group of experienced chemists and professionals that hold themselves and others to the highest quality and scientific standards. Our staff comes with extensive backgrounds working at both other cannabis labs and across many other scientific industries. Pacific Star Labs takes pride in only hiring the most competent team members,
providing first-class training, 
and professional development opportunities. By valuing quality over quantity, Pacific Star Labs offers not only premier lab testing services, but also exceptional customer service above-and-beyond the industry norm.
Our Team
David Winternheimer, PhD, PPM General Manager
David has founded and advised more than 8 start-ups over the past decade in business development leadership positions, enabling many of them to achieve profitability and/or exit opportunities in their first years of operation. In addition to deep experience in sales/marketing, he also provides technical expertise to the team. David received his PhD in organic chemistry from UCLA and his Postdoctoral Professional Masters in Bioscience Management (PPM) from the Keck Graduate Institute of Applied Life Sciences.

Sam Alcantar, BS 
Lab Director
Sam was one of the early scientists at one of the first cannabis testing labs in California, and has experience operating or advising additional cannabis labs with all California-mandated analytical chemistry assays. With over 5 years of experience testing cannabis, he is a true expert in the field. Sam received his BS in chemistry from UCSB where he contributed to publications on thin films and nano-electronics.
James Borgese, BS
Lead Scientist
James is one of the first chemists to have worked in heavy metal (ICP-MS) analysis in cannabis. As lead scientist, he is responsible for much of Pacific Star Labs’ method development/validation and continues to contribute to method optimization. James attended UC Berkeley and received his BS in chemical engineering from CSU Long Beach.
Sheryl Silverman, BS Microbiology & Quality Managers
Sheryl has over a decade of experience in research using PCR with a background in molecular genetics. She also has over 5 years of experience in managing ISO quality systems. As both microbiology and quality managers, she oversees microbial contamination testing and the full quality management system. Sheryl received her BA in chemistry with a minor in biology from Arcadia University. 
Tommie Griffin, BS
Chemist I
Tommie has an extensive background in cannabis (both in-field cultivation and lab testing) with experience validating and operating cannabis testing procedures in both Northern and Southern California. Tommie is cross-trained on all analytical methods at Pacific Star Labs. He received his BS in Biochemistry from Humboldt State University.

Lucia Hernandez, BS -- 
Lab Assistant
Lucia is well versed in ISO 17025 processes through her tenure working at Eurofins, a leading environmental testing lab in the USA. She supports the team from sample accession through analytical batch preparation. She received her BS in biology from CSULA.
RJ Fenske 
Director of Marketing
RJ is an engagement specialist focused on people’s core needs, emotions and behavioral decisions. He brings an extensive background in digital media marketing and strategic development to improve user engagement across all mediums. He builds and nurtures the complex cross-functional groups through an ever evolving digital landscape. With a diverse background ranging from the entertainment industry, big pharma, biotech startups and health & wellness. He is devoted to enhancing global collaboration to empower better user experiences and accelerate the development of products that serve people's true needs.

Pacific Star Labs

621 W Rosecrans Ave, Suite #104
Gardena, CA  90248

(310) 538-2094