Microbiological Investigations & Risk Assessment

Investigating causal factors and assessing potential health risks are fundamental components of accurately assessing microbial contamination. Exponent’s practitioners are skilled in conducting microbial investigations, assessing microbial risk, and communicating sometimes sensitive findings to clients, regulators, and community stakeholders. We consult on a wide array of issues from biological fouling to mold contamination, and our team of scientists and engineers includes nationally recognized experts in diverse fields such as chemical, environmental, and mechanical engineering; clinical microbiology; ecology; environmental and industrial microbiology; epidemiology; food safety; industrial hygiene; occupational and environmental medicine; genetics and genomics; statistics; and toxicology. Several of our scientists are former USDA or FDA employees who can help clients interact with regulatory and public health personnel. Exponent can further assist in recall decision-making and management, root-cause analysis and corrective actions, and consequent litigation and insurance claims.
Microorganisms can be found in all natural environments. Sometimes, they have beneficial roles, including the degradation of harmful materials and antibiotic synthesis. Microorganisms are detrimental, however, when present in the wrong place or at high concentrations. Deleterious effects from microbial contamination can occur across a wide variety of industrial settings and commercial products, and the effects from contamination can vary dramatically.

Exponent practitioners regularly perform microbiological investigations and risk assessments in the following areas:

Biological Fouling and Biocorrosion

Biological fouling, or biofouling, can be broadly defined as damage to engineered materials and processing systems that is mediated by living organisms. Oil production and distribution systems are particularly vulnerable to biofouling, and biofouling can reduce the efficiency of some plant operations, such as the cooling of process waters at utilities and industrial facilities. Drinking water systems and aquifer storage and recovery wells are also vulnerable to biofouling if proper procedures are not followed to keep microbial growth in check. At Exponent, we have assisted many clients in assessing sources of biofouling and implementing measures to remediate that fouling.

Industrial and Consumer Product Contamination

Biological, chemical, and pharmaceutical contamination is frequently associated with plant shutdowns and product recalls. Problems can result from mechanical failures, contaminated raw materials or product, materials deterioration, design defects, shipping conditions, or improper Standard Operating Procedures (SOPs) and Good Manufacturing Practices (GMPs), affecting products including foods, chemical, pharmaceuticals, medical devices, and many other consumer products. Exponent scientists and engineers can work closely with client facilities engineers, QA/QC professionals, and production staff to investigate process and product contamination events and ensure that client SOPs are properly developed and implemented.


Foodborne hazards include microbiological agents that can adulterate products and result in harm. As scientific breakthroughs improve analytical method sensitivity and provide better traceability of products across the supply and distribution chain, growers, processors, retailers and food service operators need experts to assist in addressing allegations that products made people sick. Our team understands how to communicate issues using a science-based approach, and we have the experience, skills, and staff to address foodborne illness allegations, having worked on many high-visibility microbial outbreaks.


Mold and mold spores are ubiquitous in the natural environment and commonly found in homes, office buildings, and industrial facilities. The mere presence of mold and mold spores alone is not necessarily problematic; however, excess moisture can lead to the amplification of fungi and molds. A broad range of health problems, including allergies, infections, and toxic effects, have been alleged to be related to mold exposures. Exponent consultants use a multi-disciplinary team approach to investigate the genus and species of the contaminating mold or molds, the level of mold found in products or the built environment, the amount of product in distribution, the targeted consumer population, and reports of alleged illness. Health hazard evaluations enable our clients to make informed recall and regulatory notification or remediation decisions.

Public Health Outbreaks

Exponent staff provides reactive assistance with public health outbreaks, with experience supporting public health outbreak investigations of anthrax, Coccidioides (cause of Valley Fever), Coxiella burnetii, Hanta virus, Legionella, and Noro virus, among others. Exponent also provides pro-active public health services including corporate and government pandemic and epidemic planning and corporate risk management.

Water and Wastewater

Microbial contamination of industrial water, drinking water, recreational waters, and storm water can result in significant economic, environmental, and public health impacts. Public health impacts might include harmful algal blooms or exceedances of water quality criteria for fecal indicator bacteria in public recreational areas. Land application of wastewater treatment biosolids and soil amendments can pose potential risks to the ecosystem from microorganisms including bacteria, enteric viruses, and other enteric parasites when not effectively managed. Exponent scientists and engineers have extensive experience in characterizing issues of bioburden (and other contaminants), Legionella and other microbial sampling, risk assessment and development of Legionella system management plans, reviewing system designs, evaluating targeted preventive and treatment options, and developing effective land application and soil amendment strategies.

Environmental Microbiology

Microbial biodegradation of contaminants and microbial bioremediation are common uses of microorganisms. Such techniques have been used at CERCLA sites and at sites impacted by oil releases. Next-generation genetic methods can help users better understand the species present and processes used in ecological settings to drive cleanup of impacted environments. A pivotal technological advance in the usefulness of genetic methods has been the DNA sequencing revolution. Applications of these techniques to sequence targeted DNA in a species of interest or in an entire microbial community can enable cutting-edge evaluation and remediation of natural, impacted, or manufactured environments.



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