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Three major outbreaks of salmonellosis linked to consumption of peanut butter during the last 6 years have underscored the need to investigate the potential sources of Salmonella contamination in the production process flow. We conducted a study to determine the prevalence and levels of Salmonella in raw peanuts. Composite samples (1,500 g, n = 8) of raw, shelled runner peanuts representing the crop years 2009, 2010, and 2011 were drawn from 10,162 retained 22-kg lot samples of raw peanuts that were negative for aflatoxin. Subsamples (350 g) were analyzed for the presence of Salmonella and enterohemorrhagic Escherichia coli. Salmonella was found in 68 (0.67%) of 10,162 samples. The highest prevalence rate (P0.05) was for 2009 (1.35%) compared with 2010 (0.36%) and 2011 (0.14%). Among four runner peanut market grades (Jumbo, Medium, No. 1, and Splits), Splits had the highest prevalence (1.46%; P0.05). There was no difference (P0.05) in the prevalence by region (Eastern versus Western). Salmonella counts in positive samples (most-probable-number [MPN] method) averaged 1.05 (range, 0.74 to 5.25) MPN per 350 g. Enterohemorrhagic E. coli was found in only three samples (0.030%). Typing of Salmonella isolates showed that the same strains found in Jumbo and Splits peanuts in 2009 were also isolated from Splits in 2011. Similarly, strains isolated in 2009 were also isolated in 2010 from different peanut grades. These results indicated the persistence of environmental sources throughout the years. For five samples, multiple isolates were obtained from the same sample that had different pulsed-field gel electrophoresis types. This multistrain contamination was primarily observed in Splits peanuts, in which the integrity of the kernel is usually compromised. The information from the study can be used to develop quantitative microbial risk assessments models.

Fresh beef products, such as steaks, may become contaminated with potential specified risk materials (SRMs), such as central nervous system tissue, during the fabrication of bone-in loin subprimals. The objective of this study was to evaluate current and alternative cutting methods that could be used to minimize the transfer of nervous system tissue (NST) tissue during preparation of steaks from bone-in short loins. Bone-in short loins were cut according to three methods. (i) Cutting method I-The vertebral column bones were removed prior to cutting the loin into steaks from the medial (vertebral column) to lateral (flank) side. (ii) Cutting method II--The loin was cut into steaks from the vertebral column side to the flank side prior to removal of the vertebral column bones. (iii) Cutting method III--The loin was cut into steaks from the flank side to the vertebral column side prior to removal of the vertebral column bones. Results indicated that surface areas along the vertebral column cutting line had detectable (0.10 and 0.22% NST/100 cm2) and, thus, higher potential SRM contamination than resulting steak surfaces or the cutting blade. Overall, there were no detectable (0.10% NST/100 cm2) differences in NST contamination of steaks produced by the three cutting methods. Immunohistochemical evaluation of areas on excised and ground steak surfaces indicated that regardless of cutting method, there was generally "no" to "moderate" staining, suggesting that detectable (0.137 to 0.201% NST) contamination from these samples was most likely due to peripheral nerve detection. These results imply that steaks may be cut from bone-in short loins prior to removal of the vertebral column bones without affecting the transfer of NST to resulting steaks at concentrations0.10% NST/100 cm2.

This communication deals with a longitudinal evaluation of C-reactive protein (CRP) analysis during a one-year period using a single lot of liquid control sera (3 levels) (BIOREF-CRP levels 1, 2 and 3) in different laboratories. A total of 652 sets of data were returned from 20 participating laboratories using 13 different reagent-measuring device combinations. The use of the control materials was defined in a standard operating procedure. Data was returned to the organizers on a monthly basis and questions could be asked or problems presented during the evaluation period. Although the performance of different reagents varied, the control materials were shown to be stable over the whole of the evaluation period when stored at 4-7 degrees C in a refrigerator/cold room. Typical problems were encountered, examples of which are presented here in graphical and tabular form.

Fresh beef samples (n = 1,022) obtained from two processing plants in the Midwest (July to December 2003) were analyzed for levels of microbial populations (total aerobic plate count, total coliform count, and Escherichia coli count) and for the presence or absence of E. coli O157:H7 and Salmonella. A fresh beef cut sample was a 360-g composite of 6-g portions excised from the surface of 60 individual representative cuts in a production lot. Samples of fresh beef cuts yielded levels of 4.0 to 6.2, 1.1 to 1.8, and 0.8 to 1.0 log CFU/g for total aerobic plate count, total coliform count, and E. coli count, respectively. There did not appear to be substantial differences or obvious trends in bacterial populations on different cuts. These data may be useful in establishing a baseline or a benchmark of microbiological levels of contamination of beef cuts. Mean incidence rates of E. coli O157:H7 and Salmonella on raw beef cuts were 0.3 and 2.2%, respectively. Of the 1,022 samples analyzed, cuts testing positive for E. coli O157:H7 included top sirloin butt (0.9%) and butt, ball tip (2.1%) and for Salmonella included short loins (3.4%), strip loins (9.6%), rib eye roll (0.8%), shoulder clod (3.4%), and clod, top blade (1.8%). These data provide evidence of noticeable incidence of pathogens on whole muscle beef and raise the importance of such contamination on product that may be mechanically tenderized. Levels of total aerobic plate count, total coliform count, and E. coli count did not (P > or = 0.05) appear to be associated with the presence of E. coli O157:H7 and Salmonella on fresh beef cuts. E. O157:H7 was exclusively isolated from cuts derived from the sirloin area of the carcass. Salmonella was exclusively isolated from cuts derived from the chuck, rib, and loin areas of the carcass. Results of this study suggest that contamination of beef cuts may be influenced by the region of the carcass from which they are derived.

Preevisceration carcass washing prior to bung bagging during beef slaughter may allow pooling of wash water in the rectal area and consequent spread of potential pathogens. The objective of this study was to compare protocols for bung bagging after preevisceration washing with an alternative method for bung bagging before preevisceration washing for the potential to spread enterohemorrhagic Escherichia coli, E. coli O157:H7, and Salmonella on carcass surfaces. The study evaluated incidence rates of pathogens in preevisceration wash water (10 ml) samples (n = 120) and on surface (100 cm2) sponge samples (n = 120) in the immediate bung region when bagging occurred before (prewash bagging) and after (postwash bagging) preevisceration washing. Surface sampling from postwash bagging yielded incidence rates of 58.3, 5, and 8.3%, whereas wash water sampling yielded 28.3, 1.7, and 5% for enterohemorrhagic Escherichia coli, E. coli O157:H7, and Salmonella, respectively. Surface sampling from prewash bagging yielded incidence rates of 35, 1.7, and 0%, whereas wash water sampling yielded 18.3, 0, and 8.3% for enterohemorrhagic Escherichia coli, E. coli O157:H7, and Salmonella, respectively. Results of this research indicate that the rectal area is a significant source of pathogen contamination on carcasses and that wash water is an important mechanism for potential transfer of pathogen contamination from the rectal area. Results from this study suggest that bung bagging, as proposed in this study, before (prewash bagging) rather than after (postwash bagging) preevisceration washing was generally more effective in controlling pathogen contamination and potential spread from the rectal area of carcasses.

A modified pararosaniline colorimetric method for more precise determination of formaldehyde in aqueous solution is described. Unlike earlier methods, the use of hazardous mercury reagent is not required. The optimization of reagent concentrations, the effect of varying temperature, and potentially interfering compounds are reported. Comparative data on the analysis of aqueous formaldehyde solutions shows that the modified pararosaniline method is more sensitive, more reproducible, and easier to use than the widely accepted chromotropic acid method. The slopes of the calibration lines are 0.533 AU mL ..mu..g/sup -1/ (absorbance units per (microgram per milliliter)) for the pararosaniline and 0.233 AU mL ..mu..g/sup -1/ for chromotropic acid. Both methods were used to determine indoor formaldehyde levels in two energy-efficient homes, and the findings are compared.

For determining formaldehyde, the Intersociety Committee of the American Public Health Association recommends a method using chromotropic acid (CA), and for determining total aliphatic aldehydes a method using 3-methyl-2-benzothiazolone hydrazone (MBTH). In field studies, the use of these separate methods involves performing many tasks in parallel and in duplicate. Inspection of the chemistry underlying the MBTH method suggested that the CA method might be successfully applied to MBTH-containing samples, provided that MBTH did not act as an interferent. We applied the recommended CA method to water and 0.05% MBTH impinger solutions from parallel sampling trains at six field sites, and found the mean formaldehyde levels to differ on the average by 5%. Having established that a single MBTH sample can yield both the formaldehyde and total aliphatic aldehyde contents of a sampled atmosphere we devised a combined method with improved techniques that streamlined laboratory analysis by maximizing procedural overlap.