Microbiology testing detects, counts, and identifies bacteria, yeasts, molds, viruses, and parasites in products, raw materials, water, and production environments. Food, pharmaceutical, cosmetic, medical device, and environmental sectors rely on it to release products and meet regulatory requirements.
A 2025 CDC-led study estimated that seven major pathogens caused about 9.9 million domestically acquired foodborne illnesses in the US in 2019. Meanwhile, the standards behind sterility, endotoxin, and rapid testing have moved faster in the past two years than in the previous decade. Those changes now reach from method selection to the way buyers qualify a contract microbiology lab.
Key takeaways
- Culture-based methods remain the reference. Compendial and reference methods anchor release decisions. Rapid methods must show equivalence through validation.
- USP <86> became official in May 2025. Recombinant factor C and recombinant cascade reagents now have a compendial route alongside LAL.
- USP <72> and <73> became official on August 1, 2025. They describe respiration-based and ATP-based tests for short-life products such as cell therapies.
- EU GMP Annex 1 has required a contamination control strategy since August 25, 2023. Environmental monitoring data now carries more weight in sterile release.
- Accreditation scope tells buyers more than accreditation alone. An ISO/IEC 17025 scope that names the method and matrix confirms the lab can run the exact test.
What Does Microbiology Testing Cover?
Most microbiology work falls into five categories. Each one supports a specific decision: Release a lot, verify a process, or investigate a failure.
| Test category | Question it answers | Common standards | Main sectors |
|---|---|---|---|
| Pathogen detection | Is a named pathogen present? | FDA BAM, ISO 6579-1 (salmonella), ISO 11290-1 (listeria) | Food, feed, cosmetics |
| Microbial enumeration | How many viable organisms are present? | USP <61> and <62>, ISO 4833-1, ISO 21149 | Nonsterile drugs, food, cosmetics |
| Sterility and bioburden | Is the product sterile, and what load enters sterilization? | USP <71>, ISO 11737-1 | Injectables, ophthalmics, medical devices |
| Endotoxin and mycoplasma | Are pyrogens or cell-culture contaminants present? | USP <85>, <86>, and <63> | Parenterals, biologics, devices |
| Environmental and water monitoring | Is the facility or water system under control? | EU GMP Annex 1, USP <1116>, EPA coliform methods | Cleanrooms, food plants, drinking water |
Food programs center on salmonella testing, listeria testing, and shelf-life studies. Pharmaceutical and device programs lean on sterility, bioburden, and endotoxin testing. Utilities and municipalities rely on water microbiology, led by coliform and E. coli indicators.
Culture-Based vs. Rapid Methods: How Do They Compare?
Culture-based methods grow organisms on agar or in broth, then count or identify them. They detect only living cells, which is why most reference methods still rely on them. The tradeoff is time. Sterility tests under USP <71> incubate for 14 days, and food pathogen confirmation often takes several days.
Rapid microbiological methods (RMMs) shorten that window, but “rapid” rarely means minutes. Most food pathogen PCR assays still need an enrichment step. DNA-based tests can also detect dead cells. Labs, therefore, pair rapid screens with culture confirmation of presumptive positives.
| Method | What it detects | Typical time to result | Main limitation |
|---|---|---|---|
| Plate count or broth culture | Viable organisms | 2–7 days; 14 days for sterility | Slow; misses viable but nonculturable cells |
| Real-time PCR | Target DNA or RNA | Same day to 2 days, including enrichment | Can detect dead cells; positives need confirmation |
| Immunoassay (ELISA, lateral flow) | Target antigens | 1–2 days, including enrichment | Lower specificity than PCR |
| ATP bioluminescence | Microbial ATP | Days rather than weeks for sterility-type tests | Product cells also produce ATP |
| Respiration-based (CO2 sensing) | Metabolic CO2 | Days rather than 14 days | Compendial use limited to short-life products |
| MALDI-TOF mass spectrometry | Protein profile of an isolate | Minutes per isolate | Needs a pure colony; depends on the spectral library |
| Whole genome sequencing | Full genome of an isolate | Several days after isolation | Cost and bioinformatics capacity |
Times are indicative and vary by matrix, organism, and validated method.
Regulators accept alternative methods once they are validated. For pharmaceuticals, a non-USP <71> sterility method counts as an alternative and must be validated under USP <1223> to show equivalence. For food, ISO 16140-2 sets the protocol for validating proprietary methods against a reference method. Its second edition reached the committee draft stage in 2026.
Which Standards Changed in 2025 and 2026?
Five developments now shape how manufacturers specify microbiology tests and qualify labs.
| Effective date | Standard or rule | What changed | Who it affects |
|---|---|---|---|
| July 20, 2028 (compliance) | FSMA 204 Food Traceability Rule | Compliance date moved from January 20, 2026; Congress also barred earlier enforcement | Firms handling foods on the Food Traceability List |
| December 29, 2025 (missed) | MoCRA cosmetic GMP rule | FDA has not proposed the rule and lists it as a long-term action | Cosmetic manufacturers and importers |
| August 1, 2025 | USP <72> and <73> | Respiration-based and ATP-based tests for short-life products became official | Cell and gene therapy, compounding, radiopharmaceuticals |
| May 2025 | USP <86> | Recombinant reagents for bacterial endotoxins became official as an alternative to USP <85> | Parenteral drug and device manufacturers |
| August 25, 2023 | EU GMP Annex 1 | Facility-wide contamination control strategy required for sterile products | Sterile manufacturers supplying the EU |
The endotoxin change carries the widest reach. USP states that firms using limulus amebocyte lysate (LAL) face no change under USP <86>. Switching to a recombinant reagent, however, remains a method change that runs through each firm’s change control.
The cosmetics gap matters for contract labs too. With no federal GMP rule in place, many brands treat ISO 22716 as the working benchmark. Preservative efficacy testing (USP <51> or ISO 11930) and microbial limits testing remain the core lab work.
Why Does Demand for Microbiology Testing Keep Growing?
Antimicrobial resistance is one key driver. The WHO’s 2025 global surveillance report found that one in six laboratory-confirmed bacterial infections in 2023 resisted antibiotic treatment. Between 2018 and 2023, resistance rose in more than 40% of the antibiotics monitored. That trend sustains demand for susceptibility testing, surveillance, and organism identification.
Short-life therapies are another. Cell and gene therapies often reach patients before a 14-day sterility test can finish, which explains the push behind USP <72> and <73>. Food outbreaks add a third pressure, as recent Cyclospora cases in fresh produce show. Many manufacturers outsource this work because in-house labs rarely cover every method, matrix, and organism.
How Do Buyers Evaluate a Microbiology Testing Lab?
Quality and procurement teams commonly review the following criteria before awarding microbiology work.
| Criterion | What it shows |
|---|---|
| ISO/IEC 17025 scope naming the method and matrix | The lab is accredited for the exact test, not just microbiology in general |
| FDA registration and cGMP status | Eligibility for pharmaceutical release testing under 21 CFR Part 211 |
| Method suitability and validation records | Results hold for the specific product, including preservative neutralization |
| Proficiency testing results | Performance against peer labs on blinded samples |
| Controls in the lab’s own test environment | Sterility results are not compromised by lab contamination |
| Identification capability (MALDI-TOF, sequencing) | Capacity to support out-of-specification and root-cause investigations |
| Turnaround and presumptive-positive alerts | Speed of escalation when a screen flags a pathogen |
| Data integrity controls | Audit trails and electronic records aligned with 21 CFR Part 11 |
For a structured supplier review, see our guide to contract laboratory vendor audits. Our certificate of analysis guide explains what each COA field should show.
Connect on Contract Laboratory
Contract Laboratory connects manufacturers with labs that run pathogen, sterility, endotoxin, bioburden, and environmental monitoring tests across food, pharmaceutical, cosmetic, and device matrices.
Submit a lab request and compare proposals on method, accreditation scope, and turnaround.
Manufacturers regularly post microbiology projects on the platform. Labs that publish their accreditation scope and method capabilities will stand out as standards shift toward rapid and recombinant methods.
Browse open lab requests or register your lab to respond.
This article was created with the assistance of Generative AI and has undergone editorial review before publishing.
Sources and Further Reading
- Scallan Walter EJ, et al. Foodborne Illness Acquired in the United States—Major Pathogens, 2019. Emerging Infectious Diseases. 2025;31(4).
- World Health Organization. WHO warns of widespread resistance to common antibiotics worldwide. October 13, 2025.
- US Pharmacopeia. Chapter for endotoxin testing using non-animal derived reagents published for early adoption. November 1, 2024.
- Reply to “Finding the middle way: rethinking cGMP for sterility testing of cellular therapy products”. PubMed Central.
- US Pharmacopeia. 〈72〉 Respiration-Based Microbiological Methods for the Detection of Contamination in Short-Life Products (PF briefing).
- European Pharmaceutical Review. Revised Annex 1 now effective. August 25, 2023.
- US FDA. FSMA Final Rule on Requirements for Additional Traceability Records for Certain Foods.
- ISO. ISO 16140-2:2016, Microbiology of the food chain — Method validation — Part 2.
- ISO. ISO/CD 16140-2, second edition (under development).
- Argents. MoCRA Requirements for Cosmetics Importers: 2026 Guide.
Frequently Asked Questions (FAQs)
Microbiology testing detects, counts, and identifies microorganisms in products, raw materials, water, and production environments. It supports product release, process validation, and contamination investigations across food, pharmaceutical, cosmetic, device, and environmental sectors.
It depends on the test. Plate counts usually take two to seven days. Compendial sterility testing under USP <71> takes 14 days. PCR-based pathogen screens often return results within one to two days, including enrichment.
USP <85> covers bacterial endotoxin tests using LAL reagents derived from horseshoe crab blood. USP <86>, official since May 2025, covers recombinant factor C and recombinant cascade reagents. USP treats <86> methods as alternatives to <85>.
Yes, once validated. Pharmaceutical firms typically validate alternative methods under USP <1223> to show equivalence to the compendial method. Food methods are commonly validated under ISO 16140-2 or through AOAC programs. USP <72> and <73> now describe compendial rapid tests for short-life products.
Bioburden testing counts the viable microorganisms on a product before sterilization, often under ISO 11737-1 for devices. Sterility testing checks whether a finished product contains any viable microorganisms after sterilization or aseptic processing.
Common tests include total aerobic counts, yeast and mold counts, specified organism tests, and preservative efficacy testing under USP <51> or ISO 11930. FDA has not yet issued the MoCRA GMP rule, so many brands follow ISO 22716.
A microbiology COA typically lists the lot number, the method cited, the result with units or a detection statement, the limit or specification, test dates, and the lab’s accreditation details. Labs typically flag presumptive and confirmed results separately.