Location: Quality & Safety Assessment Research
Project Number: 6040-42000-044-11-N
Project Type: Non-Funded Cooperative Agreement
Start Date: Feb 27, 2020
End Date: Sep 30, 2020
Semicarbazide (SEM) is a chemical biomarker to detect use of the restricted antibiotic, nitrofurazone. Research has indicated, however, that SEM may be developed in association with meat due to sources other than the use of nitrofurazone, such as environmental contaminants or by-products formed during food processing. The objectives of the current study are to determine: 1. Determine whether SEM may be detected in processed poultry products from birds not treated with nitrofurazone. 2. Determine what processing factor(s), such as exposure to various antimicrobial processing aids, temperature, pH, and time, may lead to the formation of SEM. 3. Determine what strategies may be employed during poultry processing to prevent formation of SEM.
Skin-on chicken breast meat samples will be removed from carcasses obtained at hot re-hang in a commercial slaughter plant. Breast meat with skin will be processed into a paste, divided into 2 g samples, and placed in 50 ml centrifuge tubes. Known concentrations (0, 0.5, 1, 2, 5, and 10 ppb) of semicarbazide (SEM) will be added to samples. Samples will be derivatized using 2-nitrobenzaldehyde, extracted using ethyl acetate, and the resulting residue prepared and analyzed in triplicate by LC-MS-MS. Laboratory-based experiments: A set of laboratory experiments will be designed to test for the formation of SEM during use of different combinations of antimicrobial processing aids and associated physical conditions. Initially, peptides and free creatine will be treated with various combinations of antimicrobials, pH’s, and exposure times to ascertain the effect of the treatment on individual amino acids present. Following treatment, peptides will be hydrolyzed and subsequently analyzed by HPLC to quantify changes in amino acid content. Treatment solutions will also be derivatized and analyzed by LC-MS-MS to quantify SEM produced as a result of treatments. This approach will allow us to determine which factors are likely to lead to SEM production. Once this is accomplished, a focused set of parameters will be applied to ground chicken meat samples as in Phase 1. The meat residue and supernatant will be analyzed for resultant SEM. Results from Phase 2 studies will be used to develop a model to describe what processing conditions (specifically chemical treatment) are expected to result in formation of SEM and what alterations to those conditions can be manipulated to prevent formation of SEM. Survey samples: Chicken meat samples will be collected in 20-24 poultry processors from across the U.S. The processors will include the 8 facilities “de-listed” by South Korea and 12-16 other facilities such that a diverse set of processing facilities will be included. Samples (legs quarters) will be collected on three different days spread across a two-week period. On each sample day, two samples will be collected, one shortly after startup and the second near the end of the processing shift (i.e. one sample soon after equipment sanitation was completed and one sample after processing has been ongoing for a long period). At each collection time, samples will be collected from at least four processing points in each processing plant, including: hot rehang, pre-chill, post-chill, and point of pack. Thus, the sampling plan will be: 24 plants x 3 sampling days x 2 sample times per day x 4 sample locations = 576 samples. For each sample, data relating to processing variables will also be collected. These data will include sample location, time, any and all processing aids and auxiliary chemicals applied, target concentration of processing aids, target pH, dwell time, temperature, application type (i.e. dip vs spray), and sanitation protocol and chemicals used in sanitation. Samples will be frozen and shipped with frozen cold packs to USNPRC for SEM analysis.