Thornton Laboratories
Thornton Laboratories Testing and Inspection Services, Inc.


Thornton Laboratories page outlining service options including Microbiological Testing and Fertilizer Testing.


Microbiological Testing

We provide a range of services to meet your needs for Safety audits, HACCAP protocols, and your in-house QC criteria. Our microbiology department performs the following tests using methodology from BAM, USDA, AOAC, USP, EPA:

Laboratory techniques include MPN, Membrane filtration, MUG/MMO, CFU and VIA. As part of our Quality Assurance program, we participate in the AOAC Laboratory Proficency Testing Program (M01)



Food Safety Audits / HACCAP:

  • Total Aerobic Plate Counts
  • Yeast & Mold Counts
  • Coliforms - Total, Fecal, E. coli
  • Salmonella
  • Listeria spp.
  • Listeria monocytogenes
  • Staphylococcus aureus
  • E. coli 0157H7

               USP 61:

  • Total Aerobic Plate Counts
  • Total Yeast & Mold Counts
  • Escherichia coli
  • Salmonella
  • Pseudomonas aeruginosa
  • Staphylococcus aureus


Organic based fertilizer requirements:

  • Salmonella
  • Fecal coliforms
  • Escherichia coli
  • Total Plate Counts




Fertilizer Testing

We provide an extensive range of analytical services to meet the needs for new fertilizer product labeling registration, production monitoring / QC product development. Chemical and physical testing is also provided for other agronomic related materials - Limestone, Coated Slow Release (CSR) products, Pesticides & Herbicides. Continued involvement with The Association of Fertilizer & Phosphate Chemists (AFPC) and state regulators (AAPFCO) enables us to inform our clientele of regulatory issues that may affect the marketplace.

We maintain membership in the following organizations - TFI, AOAC, FFAA. Analysis of Fertilizer products conform to the methodology of AOAC, AFPC, FDACS, ASTM, ISO/CEN, EPA.

When the need arises, Thornton Laboratories can provide assistance with new method development and validation -SLV for peer review and publication.


Fertilizer Analytical Services:

  • Nitrogen
  • Available Phosphate (P2O5)
  • Potassium (K2O)
  • Calcium
  • Magnesium
  • Copper
  • Iron
  • Manganese
  • Zinc
  • Chloride
  • Sulfate
  • Boron
  • Ammonia -nitrogen
  • Nitrate -nitrogen
  • Urea

Non-Nutritive Metals for State Registration:

  • Arsenic
  • Cadmium
  • Chromium
  • Cobalt
  • Lead
  • Mercury
  • Molybdenum
  • Nickel
  • Selenium


  • Fecal coliforms
  • Salmonella

For additional testing requirements and information please contact us!


Please use these forms when submitting samples: