Babcock Bottle Certification Appparatus Performance Evaluation

Abstract

The use and performance of a computer-controlled apparatus for certification of Babcock bottles used for payment testing were evaluated. The apparatus delivered mercury into the bottle neck using a syringe mounted on a motorized pump. Syringe movement and the collection and calculation of data were controlled by computer. The apparatus was evaluated using four 8% milk bottles (total volume 1.600 mL; bottles rejected if deviation was ≥0.008 mL) and four 50% short-neck cream bottles (total volume 5.000 mL; bottles rejected if deviation was ≥0.050 mL). Six milk and 5 cream bottle trials were conducted; each bottle was read 5 consecutive times for each trial. As a percentage of the rejection criteria, average repeatability was 5–6% and reproducibility was 9–10%. These values were similar for both types of bottles. The evaluation of the apparatus demonstrated acceptable within- and between- days performance in relation to the rejection criteria and volumes measured. Because the apparatus creates a closed system during certification, an additional experiment was conducted with 50% short-neck cream bottles to determine the effect of internal pressure within a bottle on volume estimates. Four trials were conducted, as previously described, using 4 control and 4 experimental bottles. Volume between the 0 and 50% marks (5 mL) was determined. Holes were drilled in the experimental bottles to eliminate internal pressure for the final 2 trials. The estimated volume of bottles under pressure was 0.0054 ± 0.0012 mL greater than without internal pressure (i.e., about 11% of the rejection criteria). We concluded that any pressure effect was small relative to other factors that affect volume determination.

SVR Chemometrics to Quantify β-Lactoglobulin and α-Lactalbumin in Milk Using MIR

“…The Kjeldahl method was performed using a Foss KT 200 Kjeltec TM (Foss Analytics, Hilleroed, Denmark). The AOAC methods (991.22) and (998.06) were used to determine the protein nitrogen and casein nitrogen content in milk [29,49]. The set of Cornell reference samples was frozen and processed in batches of six.…”

Modified Versus Producer Milk Calibration: Mid-Infrared Analyzer Performance Validation

“…The program initially focused on systematic improvement of the accuracy of chemical reference methods that are used as the basis for calibration of MIR milk analyzers. The Babcock (Barbano et al, 1988;Lynch et al, 1995Lynch et al, , 1996Lynch et al, , 1997aLynch et al, , 2003, ether extraction (Barbano et al, 1988;Lynch et al, 1996Lynch et al, , 1997aLynch et al, , 2003, Kjeldahl (Barbano et al, , 1991Lynch et al, 1998;Lynch and Barbano, 1999), and total solids methods (Clark et al, 1989a,b) for milk analysis have been optimized to improve their within-(s r ) and between-(s R ) laboratory performance, and the method performance values are included in the AOACI (2000 (Lynch et al, 1994(Lynch et al, , 1997b.…”