A standardized descriptive language for Cheddar cheese flavor was developed and validated. Representative Cheddar cheeses (240) were collected. Fifteen individuals from industry, academia, and government participated in a 3-d roundtable discussion to generate descriptive flavor terms. A highly trained descriptive panel (n = 11) refined the terms and identified references. Cheddar cheeses (24) were presented to the panel for validation with the identified lexicon. The panel differentiated the 24 Cheddar cheeses as determined by univariate and multivariate analysis of variance (P < 0.05). Twenty-seven terms were identified to describe Cheddar flavor. Seventeen descriptive terms were present in most Cheddar cheeses. A standard sensory language for Cheddar cheese will facilitate training and communication between different research groups.

The ability of reverse transcriptase PCR (RT-PCR) to detect viable Shiga-toxin-producing Escherichia coli (STEC) was investigated. Four primer sets, each targeting a specific region in the slt-II operon, were evaluated for their stringency and specificity for slt-II mRNA. STEC were evaluated for toxin expression under various conditions, including cell growth phase, growth medium, incubation temperature, and aeration. Following primer optimization, STEC were inoculated into Trypticase soy broth and cooked ground beef enrichments. Cells were harvested and RNA or DNA was extracted at 4, 8, 12, and 24 h. RT-PCR or PCR was conducted, and the products were visualized by gel electrophoresis and by Southern blots. mRNA targets were detected in 12-h cooked ground meat enrichments with an initial inoculum of 1 CFU/g. These results indicate that RT-PCR of E. coli slt-II mRNA is useful for detection of viable STEC in ground beef.Escherichia coli O157:H7 was first isolated as a human pathogen in 1982 and has since become a well-known agent of food-borne illness. Cases of hemorrhagic colitis, hemolytic uremic syndrome, and death have been reported following the consumption of raw or undercooked ground beef (8). Although most commonly associated with foods of animal origin, enterohemorrhagic E. coli (EHEC) may also be isolated from contaminated drinking water and acidic foods such as mayonnaise, salad dressings, and buttermilk (6,16,29). The infectious dose for E. coli O157:H7 and other serotypes of EHEC varies greatly between populations. For susceptible individuals such as the elderly and infants, the infectious dose may be as low as 10 cells (8).Without an animal model, there is much controversy over which virulence factors of EHEC contribute to human pathogenicity (8). EHEC produce Shiga-like toxins (SLTs) that characterize this group of pathogenic E. coli. Other virulence markers include intimin, hemolysin, and the locus of enterocyte effacement (8). Food-borne illnesses have occurred with isolates that possess all or only a few of these markers (8, 9). Possession of slt genes is a consistent virulence marker (1), but without evidence of human illness, E. coli possessing slt are often referred to as Shiga toxin-producing E. coli (STEC). Despite the fact that EHEC strains containing slt-I and slt-II have been isolated from patients with hemorrhagic colitis, studies have shown that strains possessing only slt-II are more frequently associated with human disease complications (8, 25).Molecular methods for the detection of E. coli O157:H7 are becoming more widely accepted as an alternative to traditional growth-based tests. The ability to specifically identify the presence of an organism within a fraction of the time required by standard approaches makes molecular tests ideal for use in food systems (2). A number of recent reports have applied molecular tools for specific detection of pathogenic E. coli in food systems (10,24,31,32). Most of these assays have used DNA as the target molecule; however, recent literature has sh...

The effects of contamination point (during fermentation versus postfermentation) and storage temperature (5 and 12 degrees C) were determined for survival of Escherichia coli O157:H7 in fermented buttermilk. E. coli O157:H7 was recovered from buttermilk inoculated during fermentation for 22 days and in buttermilk inoculated postfermentation for 32 days. For storage temperatures of 5 and 12 degrees C, D-values were lower for E. coli O157:H7 inoculated during fermentation (2.5, 2.2 days) than postfermentation (5.6, 4.8 days) (P < 0.05). Developed acidity in inoculated buttermilks was not different from controls (P > 0.05). The extended recovery of viable enterohemorrhagic E. coli O157:H7 from both processing scenarios indicates that the presence of E. coli O157:H7 in buttermilk is not limited to postprocessing contamination.