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Submitted to: Journal of Association of Official Analytical Chemists International
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/1/1998 Publication Date: N/A Citation: N/A Interpretive Summary: FSIS of the USDA requires that certain meat and poultry products be heat processed to specific internal temperatures. FSIS has requested new and/or improved methods for determining the end-point temperature (EPT) to which meat and poultry products have been heat processed. Acid phosphatase (ACP) is a heat liable enzyme present in poultry muscle which decreases in cooked(155F/68.3C to 165F/73.88C) breast and thigh meat. This method is applicable for the determination of acid phosphatase (ACP) in boneless broiler cooked marinated and non-marinated breast and thigh and a 50/50 blend of breast and thigh meat cooked in about 11 to 12 min. Results showed that marinated products and thigh meat had higher ACP activity than non-marinated and breast product. Consequently, it would be necessary to regulate these products separately. This assay could provide a rapid (3 min instrument--15 min sample preparation), sensitive, and easy-to-use assay for a HACCP quality assurance/process control monitoring program in cooked poultry for both poultry processors and FSIS. Technical Abstract: This method is applicable for the determination of acid phosphatase (ACP) activity in cooked boneless, non-breaded broiler marinated (83.65% meat) and non-marinated (100% meat) breast and thigh and a 50:50 blend of breast and thigh meat. This assay uses a self-indicating substrate which, when acted upon by ACP becomes a highly fluorescent compound. Cooked meat is added to distilled water in a 1:3 ratio and blended with a hand-held homogenizer, then centrifuged at 2500 RCF for 5 min. ACP is measured in the filtrate after mixing a 75 uL aliquot of the extract with a pH 5.00 buffer with substrate. The rate of fluorophore formation is monitored during a 3 min incubation (38C) period in a fluorometer and ACP activity in mU/kg of sample calculated. Three laboratories analyzed 6 cooked products. Five cooking temperatures were used to generate different ACP activity levels which was replicated twice with duplicate samples and duplicate sample tests representing 720 data points. Log 10 ACP activity (mU/kg of sample) performance repeatability and reproducibility standard deviations [s(r) and s(R)] and relative standard deviations [RSD(r) and RSD(R)] over 5 cooking treatments for 6 products were as follows: Marinated Breast; s(r)=0.02, s(R)=0.08, RSD(r)=0.60%, RSD(R)=2.12%: Non-marinated Breast; s(r)=0.02, s(R)=0.04, RSD(r)=0.66%, RSD(R)=1.29%; Marinated Thigh; s(r)=0.01, s(R)=0.01, RSD(r)=0.37%, RSD(R)=0.37%; Non-marinated Thigh; s(r)=0.02, s(R)=0.05, RSD(r)=0.53%, RSD(R)=1.43%; Marinated 50/50 Breast & Thigh; s(r)=0.01, s(R)=0.05, RSD(r)=0.36%, RSD(R)=1.31%; Non-marinated 50/50 Breast & Thigh; s(r)=0.01, s(R)=0.04, RSD(r)=0.32%, RSD(R)=1.12%. |
