Analysis of Salmonella serotypes from selected carcasses and raw ground products sampled prior to implementation of the Pathogen Reduction; Hazard Analysis and Critical Control Point Final Rule in the US

In July 1996, the US Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS), published the Pathogen Reduction; Hazard Analysis and Critical Control Point (HACCP) Systems final rule to improve food safety of meat and poultry products. The final rule established, among other requirements, pathogen reduction performance standards for Salmonella for food animal carcasses and raw ground products. The final rule is to be fully implemented in three stages in successively smaller federally inspected meat and poultry slaughter and processing establishments. Implementation began in January 1998 and was completed in January 2000. Samples of carcasses of four species of food animals (cattle, swine, chickens, turkeys), and raw ground product from each of these species, were collected by FSIS from establishments prior to implementation of the final rule and cultured for Salmonella. This paper reports Salmonella serotype results of samples collected from June 1997 through August 1998. These results represent a baseline for future comparisons.     

Quantitative probing the interfacial structure of TPO/CPO blends by transmission electron microscopy via EDX

High-resolution scanning transmission electron microscope (HR STEM) measurements were performed on a thermoplastic polyolefin (TPO) substrate coated with chlorinated polyolefin (CPO). This CPO was a maleated chlorinated polypropylene containing 21.8 wt% Cl. The TPO investigated was a blend of high-modulus isotactic polypropylene (iPP) with a crystalline ethylene-butene copolymer (EB9) containing 9 wt% butene. For these injection-molded samples, examined ca. 10 mm from the mold gate, a stratified morphology found at TPO surface consisting of thin fibers of EB9 trapped in a transcrystalline iPP matrix, with crystalline lamellae propagating from the matrix across the EB9 domains. This structure was unperturbed when the plaques were coated (from tetrahydrofuran solution) with a 5 μm layer of CPO, but underwent changes of increasing severity when subjected either to a dry bake at 120 °C or annealing at 120 °C in the presence of xylene vapor. The interfacial structure between the CPO and the TPO was probed by TEM with energy dispersive X-ray imaging (EDX). The elemental chlorine across the interface gave good fits to a tan h function, and the interface thickness increased from 23 ± 2 nm to 28 ± 1 nm upon annealing at 120 °C for 30 min. After annealing in the presence of xylene vapor, this value increased to 50 ± 4 nm. As reference points, we determined an interface thickness of 29 ± 3 nm for the CPO-EB interface and 15 ± 2 nm for the interface between CPO and iPP.     

Structure/property relationships in flexible alkoxysilane automotive coatings

Flexible automotive coatings are susceptible to scratch and mar damage, especially during finishing and assembly operations. One-component (1K) flexible clearcoats exhibit very good scratch and mar resistance, but unfortunately suffer from poor durability and environmental etch resistance. Two-component clearcoats offer improvements in both etch and durability, but at the expense of scratch and mar. In this paper, the concept and properties of 1K flexibilized silane clearcoats for use on automotive plastics will be introduced and their structure/property relationships examined as they apply to scratch and mar. The role of coating crosslink density, toughness, glass transition temperature (T_g), and surface profile on the scratch damage of coated plastic substrates will be described. In addition, a new scratch methodology, termed Scratcho, is utilized to determine relative scratch performance and is compared to conventional scratch resistance testing. Results to date indicate that hardness, as affected by the glass transition temperature, and crosslink density, as it contributes to higher essential work values, both affect resultant scratch propensity of the flexible coatings. The relative ranking of different coating systems employing alternate crosslinkers (e.g., isocyanate and melamine) is also presented and compared to the newly developed silane crosslinked coatings. Presented at the 28th International Waterborne, High-Soids, and Powder Coatings Symposium, Feb. 21–23, 2001, in New Orleans. LA. 377 Fairall St., Ajax, Ont., L1S 1R7, Canada. 401 Southfield Rd., P.O. Box 6231, Dearborn, MI 48121-6231.