Adulterants in Whiskey: Detection and Identification by Principal Component Analysis

Model adulterants such as gasoline, phenol, rubber hose, and hair were added to whiskies to prepare adulterated samples. Methylene chloride extracts of these and of the unadulterated whiskies were separated by capillary column GC. Principal Component Analysis was applied to the gas chromatograms, and the resulting scores were used to decide upon product acceptability. Using a series of standards, scores were also the basis for identification of adulterants in rejected samples. In the largest of three data sets, decisions were correct for over 95% of samples, and all adulterated samples were correctly identified.     

A COMPARATIVE STUDY OF HEAT PENETRATION DATA USING REMOTE SENSORS AND NEEDLE OR ROD-IN-TUBE THERMOCOUPLES

Using 5% w/v bentonite suspension as model food, studies were conducted to evaluate the performance of internally mounted remote sensors relative to thermocouples in 300 × 407 cans. These studies were done to essentially evaluate the impact of remote sensors on heat penetration parameters, mainly j_h (the lag factor) and f_h (the heating rate index), for different retort rpm, container headspace (HS) and mode of agitation in FMC's Steritort (FMC Food Tech, Madera, CA) and/or the Allpax R&D retort (Model 2402, Covington, LA). The criterion used for evaluating the performance of the sensors was the Ball process time (B_b), which combines both j_h and f_h. Generally, some variations in heat penetration data were observed between remote sensor types and thermocouples. With some exceptions, calculated mean B_b values for the remote sensors and thermocouples were statistically insignificant (P > 0.05). The exceptions depended on the remote sensor type and mode of container agitation, but generally, variations in measured parameters from that of the reference thermocouple were attributed to container HS, retort rpm, sensor configuration and mounting fixture design. For axial agitation in the Steritort using 300 × 407 two‐piece cans, the average Ball process times were generally higher (i.e., longer process times) for thermocouples compared to the remote sensors with the percentage difference ranging from 2 to 7%. The range was 2 to 8% for end‐over‐end agitation with water immersion, and 1 to 6% for still cook in steam using the Allpax R&D retort using 300 × 407 three‐piece cans. Given the unusually high percentage differences found for some of the experimental conditions, caution must be exercised in using these variations as correction factors in adjusting remote sensor data without a thorough understanding of the behavior and interaction of that specific sensor with HS and retort rpm.     

ELEMENTARY SCHOOL DIFFICULTIES OF LOW‐INCOME LATINO AND AFRICAN AMERICAN YOUTH: THE ROLE OF GEOGRAPHIC CONTEXT

Do the geographic contexts in which disadvantaged children are raised influence whether they have difficulties in elementary school? We address this question by estimating Cox proportional hazard models with instrumental variable measures of context, using data for 410 low‐income Latino and African American children who lived in Denver public housing before age six. The Denver Housing Authority's procedure for allocating families to dwellings mimics random assignment, thus offering an unusual natural experiment for measuring context effects isolated from geographic selection bias. We find that several socioeconomic and demographic contextual indicators are statistically and substantively important predictors of low‐income Latino and African American children's difficulties in elementary school, though sometimes in nonlinear and interactive ways. Generally, the hazard of being assigned to special education classes, suspended, or forced to repeat a grade is greater in neighborhoods with higher occupational prestige and percentages of immigrants and lower in those with higher percentages of African American residents.     

THE NEW DISTRICT OF COLUMBIA: WHAT POPULATION GROWTH AND DEMOGRAPHIC CHANGE MEAN FOR THE CITY

The District of Columbia was a magnet for new residents in the first part of the twenty‐first century. Drawn by good jobs, new condos, and burgeoning entertainment districts, the city attracted thousands of young professionals who might have otherwise settled in the region's suburbs. At the same time, some of the District's longer‐term residents are leaving the city. The growing population provides a boon to the city, but is also leads to an increasing social, economic, and cultural divide. Between 2000 and 2010, the District of Columbia gained nearly 30,000 people. The 5.2% population growth in the last decade marks a turnaround for the city, which has lost residents in every decade since 1950. Population growth was fueled by an influx of white residents and an unprecedented loss of African Americans. This article explores the population and demographic trends in the District of Columbia between 2000 and 2010 by examining the socioeconomic characteristics of the city's in‐migrants, out‐migrants, and non‐movers to explore evidence of gentrification. Using microdata from the 2006–2010 American Community Survey, this research also uses logistic regression to analyze the factors associated with out‐migration from the city and movement within the city.     

INHIBITION OF SALMONELLA TYPHIMURIUM ON POULTRY BY THE LACTOPEROXIDASE SYSTEM1

The antibacterial activity of the lactoperoxidase (LP) system on the growth and survival of a naladixic acid resistant strain of Salmonella typhimurium on poultry was determined. The LP system treatment, which consisted of lactoperoxidase (1 μg/ml), potassium thiocyanate (5.9 mM), and hydrogen peroxide (2.5 mM) (final concentrations) in water, reduced the level of Salmonella on inoculated chicken legs. The magnitude of reduction was dependent on temperature and time. For a water temperature of 25C and a time of 30 min, a 13.2% reduction was seen, as compared to a water temperature of 60C and a time of 15 min which showed a 80.6% reduction. In a 48 h shelf-life study, the LP system controlled growth of psychrotrophic bacteria on chicken legs. Hunterlab color values (L, a, b) for chicken thigh skin and oxidative deterioration as measured by TBA values for chicken thigh meat did not significantly differ (p < 0.01 and p < 0.05, respectively) between control and treated thighs.     

PROTEOLYTIC ACTIVITY OF LACTOBACILLUS SAKEI, LACTOBACILLUS FARCIMINIS AND LACTOBACILLUS PLANTARUM ON SARCOPLASMIC PROTEINS OF PORK LEAN

The aim of this study was to assess the proteolytic activity of Lactobacillus sakei (DSM 6333), L. plantarum (B21), and to a lesser extent, L. farciminis (DSM 20184) on meat sarcoplasmic proteins. The protein composition was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and capillary electrophoresis after incubation of meat extract inoculated with bacteria. All strains showed proteolytic activity: a band about 94 kDa disappeared in samples inoculated with L. farciminis and L. plantarum and strongly decreased in those inoculated with L. sakei. The intensity of the bands with a molecular weight between 94 and 38 kDa decreased in all samples. Capillary electrophoresis analysis ascertained the disappearance of the fractions corresponding to 8.64 and 8.66 min retention time in all samples. The bands corresponding to 94 kDa and 38 kDa were, respectively, identified as glycogen phosphorylase muscle isoform and glyceraldehyde 3-phosphate dehydrogenase, by in situ digestion of protein gel bands and peptide map analysis using Matrix Assisted Laser Desorption/Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS).     

DIFFERENTIAL SCANNING CALORIMETRY DETECTION OF HIGH OLEIC SUNFLOWER OIL AS AN ADULTERANT IN EXTRA-VIRGIN OLIVE OIL

Differential scanning calorimetry (DSC) was employed to detect high oleic sunflower oil (HOSo) as an adulterant in extra-virgin olive oil (EVOo) by means of cooling and heating thermograms. Addition of HOSo did not significantly alter cooling profiles of EVOo except for onset temperature of crystallization, which was significantly shifted toward lower temperature at 40% of adulterant addition. At the same percentage of adulteration, the heating profile of EVOo was significantly changed as the major endotherm broadened and the minor event became smaller and less evident. Cooling thermograms of pure oils and their admixtures were deconvoluted into three constituent exothermic peaks in an attempt to detect addition of HOSo at levels lower than 40%. Thermal properties of the two lower-temperature exotherms (area percentage, offset temperature and range of transition) were significantly changed at ≥ 20% of HOSo substitution, suggesting that DSC can be employed to detect this oil as an EVOo adulterant.

PRACTICAL APPLICATIONS

Adulteration of extra-virgin olive oil (EVOo) with cheaper oils from other vegetable sources or seeds, as well as with lower quality olive oils, is a serious concern for oil suppliers and consumers and requires the use of new analytical techniques for their detection. Differential scanning calorimetry (DSC) exhibits some advantages over the classical analytical methods as it does not require sample preparation and use of solvents, thus resulting in a reduced environmental impact. Results suggested that its application to the detection of EVOo adulteration with high oleic sunflower oil, a vegetable oil largely employed for this type of fraud, is promising with the support of the deconvolution analysis of cooling thermograms.