Production of shelf-stable ranch dressing using high-pressure processing.

High-pressure processing (HPP) can reduce or eliminate microorganisms of concern in food without deteriorating product quality; however, quality benefits must justify the substantial capital investment for the utilization of this technology. HPP is particularly a beneficial preservation technology for products damaged by thermal treatments or when product quality could be improved by reformulation to raise pH or eliminate chemical preservatives. The primary objectives of this study were to determine the efficacy of HPP to protect premium ranch dressing (pH 4.4) from microbial spoilage and to assess changes in physical, chemical, and sensory attributes throughout the product's shelf life. In inoculated-packages studies, the efficacy of HPP was measured against ranch dressing spoilage organisms: Pediococcus acidilactici, Lactobacillus brevis, and Torulaspora delbrueckii. HPP treatment (600 MPa, 3 min) decreased population of P. acidilactici, the most pressure-resistant spoilage organism tested, by >or= 6.4 log CFU/g. During a shelf-life study of edible product, treating ranch dressing at 600 MPa for 5 min effectively prevented microbial spoilage throughout the storage period (26 wk at 4 and 26 degrees C). The pH and emulsion stability of ranch dressing were not adversely influenced by HPP. Extended storage of HPP product for 16 to 26 wk at 26 degrees C resulted in a decrease in consumer acceptance and significant changes in color and organic acid profile (specifically, increased pyroglutamic acid). These changes were consistent with those expected during extended storage of commercially available products. HPP may be used to produce premium ranch dressing, with defined shelf-life and storage conditions, without significantly changing product attributes.

Outbreak of tick-borne relapsing fever at the north rim of the Grand Canyon: evidence for effectiveness of preventive measures.

An outbreak of tick-borne relapsing fever (TBRF) originating at the North Rim of Grand Canyon National Park was investigated in 1990. To determine risk factors for the disease, almost 7,000 parties of visitors were surveyed; over half responded, representing > 10,000 people. Fifteen cases of confirmed or probable TBRF were identified in visitors and 2 in employees. All patients except one experienced symptoms after overnight stays in a group of cabins that had not been rodent-proofed after a TBRF outbreak in 1973 (relative risk for visitors [RR] 8.2, 95% confidence interval [CI] 1.1-62). Seven cases of TBRF were associated with a single cabin (RR 98, 95% CI 30-219). Structural flaws and rodent nests were common in the implicated cabins and rare in unaffected cabins. This investigation suggests that measures to rodent-proof cabins at sites where TBRF is endemic prevent reinfestation of cabins by infected rodents and tick vectors, thereby preventing the spread of disease in humans.

Predictors of cesarean section delivery among college-educated black and white women, Davidson County, Tennessee, 1990-1994.

Cesarean section delivery increases the cost, morbidity, and mortality of childbirth. Cesarean section rates vary nationwide with the highest rates occurring in the southern United States. The Department of Health and Human Services has published year 2000 objectives that include a 15% reduction in the cesarean section rate. This study identified factors contributing to cesarean section delivery among a cohort of college-educated black and white women in Davidson County, TN. Logistic regression models were applied to Linked Infant Birth and Death certificate data from 1990-1994. Data on singleton first births for 606 black women and 3661 white women completing 16 years of education were analyzed. College-educated African Americans were at a significantly higher risk of cesarean section delivery than whites. This difference could not be accounted for by controlling for all other variables. The geographic differences in cesarean section rates in this country may be the result of varying in provider practice styles, perceptions, or attitudes. Improving the health of women and children will require establishing a system of maternity care that is comprehensive, case-managed, culturally appropriate, and available to all women.

Two-fiber spectroscopic probe with improved scattered light rejection.

Our angled two-fiber probe design for in situ spectroscopic measurements (e.g., fluorescence, phosphorescence, or Raman) through a sapphire window has been modified to provide improved rejection of scattered excitation light while maintaining good efficiency of collection of the desired signal. The improvement is achieved by changing the probe axis to an off-normal configuration to minimize back reflection from window surfaces while maximizing the overlap of the light cones of the excitation and collection fibers at the outer window surface where the sample is in contact with the window. The results of laser-induced fluorescence measurements on phenol solution and sand samples, demonstrating the improved performance of the new probe, are reported. Up to 90-fold improvement in the fluorescence/scattered light ratio has been observed with the new probe.

Predictors of infant mortality among college-educated black and white women, Davidson County, Tennessee, 1990-1994.

Strategies to reduce US infant mortality rates often focus on the black-white disparity in rates. Linked Infant Birth and Death Files for Davidson County, Tennessee, from 1990 through 1994 were used to determine infant outcomes for infants born to college-educated white and black women. Risks for adverse outcomes were identified by comparing infant deaths to live births using logistic regression analyses. The following variables entered the logistic model process: maternal and paternal age; race and education; nativity status; maternal risk factors; interpregnancy interval; parity; infant gender; tobacco or alcohol use; number of prenatal visits; trimester in which prenatal care began; marital status; gestational age; and birthweight. After adjustment for the effects of the other variables, a gestational age < 28 completed weeks of gestation was the most significant independent predictor of infant death. Black race was not identified as a significant predictor of infant mortality. Regardless of race, a decrease in infant mortality rates among college-educated women in this country depends on the prevention of preterm births. Strategies to diagnose early preterm labor must proceed from a comprehensive maternal care program for all women. Open channels of communication between patient and provider will form the cornerstone for preterm prevention-intervention programs. Analysis of state and local infant mortality data may identify regional differences in infant mortality rates and differences in risk factors associated with adverse infant outcomes.