|HAN, LIJUN - China Agricultural University|
|JOHNSTON, JOHN - Food Safety Inspection Service (FSIS)|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2015
Publication Date: 11/5/2015
Publication URL: http://handle.nal.usda.gov/10113/62934
Citation: Lehotay, S.J., Sapozhnikova, Y.V., Han, L., Johnston, J.J. 2015. Analysis of nitrosamines in cooked bacon by QuEChERS sample preparation and gas chromatography – tandem mass spectrometry with backflushing. Journal of Agricultural and Food Chemistry. 63:10341-10351.
Interpretive Summary: For food safety purposes, the USDA Food Safety and Inspection Service (FSIS) needed to conduct a new risk assessment of nitrosamines in cooked bacon. However, FSIS did not have current monitoring results to determine consumer exposure, which was needed for the assessment. The previous monitoring method could no longer be used because the instrumentation was not available. We developed a new method of analysis to meet FSIS needs, and used the method to analyze the 5 nitrosamines of interest in 48 cooked bacon samples collected from around the country. Method validation results were acceptable, and the nitrosamine concentrations found demonstrated that nitrosamines in cooked bacon do not pose a significant consumer risk that warrants their further monitoring in the National Residue Program at this time.
Technical Abstract: Nitrites are added as a preservative to a variety of cured meats, including bacon, to kill bacteria, extend shelf-life, and improve quality. During cooking, nitrites in the meat can be converted to carcinogenic nitrosamines (NAs), the formation of which are mitigated by the addition of anti-oxidants. In the past, the United States Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) monitored NAs in pan-fried bacon, but FSIS terminated monitoring of NAs in the 1990s due to the very low levels found. FSIS recently chose to conduct a risk assessment of NAs in cooked bacon to determine if current levels warrant routine monitoring of NAs again. To meet FSIS needs, we developed, validated, and implemented a new method of sample preparation and analysis to test cooked bacon for 5 NAs of most concern, which consist of N-nitroso -dimethylamine, -diethylamine, -dibutylamine, -piperidine, and -pyrrolidine. Sample preparation was based on the QuEChERS (quick, easy, cheap, effective, rugged, and safe) approach and analysis by gas chromatography – tandem mass spectrometry. Ruggedness was improved markedly in the analysis of the complex fatty extracts by backflushing the guard column, injection liner, and half of the analytical column after every injection. Validation results were acceptable with recoveries of 70-120% and <20% RSDs for the 5 NAs, with a reporting limit of 0.1 ng/g. NA concentrations in 48 samples were all <15 ng/g, with most <1 ng/g and many <0.1 ng/g. Also, microwave cooking of bacon gave slightly lower concentrations overall compared to pan-frying.