Software-Assisted Pattern Recognition of Persistent Organic Pollutants in Contaminated Human and Animal Food.

Persistent Organic Pollutants (POPs) are a serious food safety concern due to their persistence and toxic effects. To promote food safety and protect human health, it is important to understand the sources of POPs and how to minimize human exposure to these contaminants. The POPs Program within the U.S. Food and Drug Administration (FDA), manually evaluates congener patterns of POPs-contaminated samples and sometimes compares the finding to other previously analyzed samples with similar patterns. This manual comparison is time consuming and solely depends on human expertise. To improve the efficiency of this evaluation, we developed software to assist in identifying potential sources of POPs contamination by detecting similarities between the congener patterns of a contaminated sample and potential environmental source samples. Similarity scores were computed and used to rank potential source samples. The software has been tested on a diverse set of incurred samples by comparing results from the software with those from human experts. We demonstrated that the software provides results consistent with human expert observation. This software also provided the advantage of reliably evaluating an increased sample lot which increased overall efficiency.

QUICK: Quality and Usability Investigation and Control Kit for Mass Spectrometric Data from Detection of Persistent Organic Pollutants.

Persistent organic pollutants (POPs) cause a significant public and environmental health concern due to their toxicity, long-range transportability, persistence, and bioaccumulation. The US Food and Drug Administration (FDA) has a program to monitor POPs in human and animal foods at ultra-trace levels, using gas chromatography coupled with mass spectrometry (GC-MS). Stringent quality control procedures are practiced within this program, ensuring the reliability and accuracy of these POP results. Due to the complexity of this program's quality control (QC), the decision-making process for data usability was very time-consuming, upward of three analyst hours for a batch of six extracts. We significantly reduced this time by developing a software kit, written in Python, to evaluate instrument and sample QC, along with data usability. A diverse set of 45 samples were tested using our software, QUICK (Quality and Usability Investigation and Control Kit), that resulted in equivalent results provided by a human reviewer. The software improved the efficiency of the analytical process by reducing the need for user intervention, while simultaneously recognizing a 95% decrease in data reduction time, from 3 hours to 10 minutes.

Application of a High-Resolution Quadrupole/Orbital Trapping Mass Spectrometer Coupled to a Gas Chromatograph for the Determination of Persistent Organic Pollutants in Cow's and Human Milk.

A quadrupole/orbital trapping mass spectrometer or Q-Exactive (QE) interfaced with a gas chromatograph (GC) was optimized for measuring polychlorinated dibenzo- p-dioxins, dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs) in foods. Figures of merit include (1) an instrument detection limit (IDL) for 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) of 9 femtograms (fg), (2) quantitative mass resolution from PCDD interferences (e.g., PCBs, methoxy-PCBs DDTs, polychlorodibenzylphenyl ethers, polychloroxanthenes, methyl-polychlorodibenzofuran, and polychlorodibenzothiophenes), and (3) mass accuracy <1 ppm at the IDL. The QE measured the concentrations of PCDD/Fs and PCBs in whole cow's milk with no known source of contamination (e.g., TCDD 33 fg/g fat). A National Institute of Standards and Technology (NIST) unfortified human milk standard reference material (SRM) 1953 was measured determining 27 PCDD/F and PCB congeners with an average difference of 7.6% from the certified results. The QE-GC is a benchtop instrument, easy to service, easy to operate, and requires no lock masses, mass preselection, or chemical ionization conditions. The QE-GC demonstrated that it can be an alternative to the double focusing magnetic sector instruments (sector) for the high-resolution measurement of PCDD/Fs and PCBs in dairy products.