Biogenic amine and microbiological profile of Serbian dry fermented sausages of artisanal and industrial origin and associated health risk

ABSTRACT

From the public health point of view, safety of dry fermented sausages is of concern due to possible presence of biogenic amines and some other food hazards. Taking into consideration that biogenic amines are chemical indicators of microbiological contamination, industrial and artisanal dry fermented sausages produced in Serbia were subjected to the microbiological and biogenic amine profiling. Microorganisms identified by MALDI-TOF MS included Cronobacter sakazakii and Listeria innocua, whereas the food pathogens were not detected. Biogenic amine content, determined by HPLC method in the range from 37.3 to 1186 mg/kg, was characterised as very low to low in 40% of the samples, moderate in 38%, high in 14% and very high in 8%. Risk assessment revealed that consumption of dry fermented sausages could cause histamine and tyramine intake up to 11.9% and 3.4% of threshold dose for healthy population, respectively. Adverse health effects would be rather unlikely for general population.     

Distance delivery of nutrition education.

Questions often arise about the quality of an educational experience in a distance format. Debate exists as to whether the relatively new format of on-line education can offer an equivalent learning experience for students, and the perception remains that virtual learning is impersonal. We examined students' experience in an introductory undergraduate nutrition course that had been remodelled as an asynchronous, active-learning, student-centred model. The investigation used the framework of instructional message design, a concept based on cognitive science principles, to highlight themes in student survey and focus group data. Results indicate that a motivating and accessible quality educational experience is possible in an on-line format through a student-centred model. Such a model provides a means to offer education to a diverse and larger audience. Further investigation is needed to determine faculty professional development needs and cost-effective ways to expand the model. Such a model provides alternatives to expand delivery to encourage interest in the field, and to provide continuing education for allied professionals and the general public.     

Evaluation of the vehicle inspection/maintenance program in the Metropolitan Area of Mexico City

The Inspection/Maintenance Program in the Metropolitan Area of Mexico City (MAMC) mandates a test every 6 months for all gasoline motor vehicles as one of the strategies to decrease emissions of vehicular pollutants. FTP-75 and ASM procedures were performed in our facilities to a fleet of 108 in-use motor vehicles before and after the approval of the I/M mandatory test When our laboratory-simulated ASM data were compared with those of the official certificate, a large difference was observed between them. On the other hand, audits at the test-only centers indicate poor maintenance of the analytical instruments and dynamometers. On the basis of our FTP results, an estimation of the emissions change for the MAMC fleet shows a net 4% decrease in CO emissions, while total hydrocarbons and NOx increased 9 and 8%, respectively. Our results indicate that the I/M system in the MAMC lacks the technical capability and investment to ensure that software and hardware are properly maintained, calibrated, and upgraded. Sometimes limited attention is paid to ensure adequate training of inspectors, auditors, and quality control staff.     

Environmental implications on the oxygenation of gasoline with ethanol in the metropolitan area of Mexico City

Motor vehicle emission tests were performed on 12 in-use light duty vehicles, made up of the most representative emission control technologies in Mexico City: no catalyst, oxidative catalyst, and three way catalyst. Exhaust regulated (CO, NOx, and hydrocarbons) and toxic (benzene, formaldehyde, acetaldehyde, and 1,3-butadiene) emissions were evaluated for MTBE (5 vol %)- and ethanol (3, 6, and 10 vol %)-gasoline blends. The most significant overall emissions variations derived from the use of 6 vol % ethanol (relative to a 5% MTBE base gasoline) were 16% decrease in CO, 28% reduction in formaldehyde, and 80% increase in acetaldehyde emissions. A 26% reduction in CO emissions from the oldest fleet (< MY 1991, without catalytic converter), which represents about 44% of the in-use light duty vehicles in Mexico city, can be attained when using 6 vol% ethanol-gasoline, without significant variation in hydrocarbons and NOx emissions, when compared with a 5% vol MTBE-gasoline. On the basis of the emissions results, an estimation of the change in the motor vehicle emissions of the metropolitan area of Mexico city was calculated for the year 2010 if ethanol were to be used instead of MTBE, and the outcome was a considerable decrease in all regulated and toxic emissions, despite the growing motor vehicle population.     

Evaluation of edible film-forming ability of pumpkin oil cake; effect of pH and temperature

This study was conducted to evaluate the feasibility of pumpkin oil cake (PuOC) to form biodegradable films. The effect of heating treatment and pH of film solutions on films properties was determined. Film with the highest tensile strength (TS) (68.08 MPa) and elongation to break (EB) (36.62%) was produced when pH was 12 and heating T 90 °C. The same showed the best permeability properties. The total soluble matter and soluble protein reached the highest value, when the film was prepared at pH = 12 and T = 50 °C. ABTS test indicated that the film produced at pH = 10 and T = 60 °C was the best regarding the radical scavenging activity. Moisture content had not been significantly affected by the pH and heating temperature, whereas swelling capacity could be measured only for film prepared at T = 80 and 90 °C. To affirm and explain the influence of pH and T, scanning electron microscopy (SEM) was used.     

Polyfluorinated compounds in residential and nonresidential indoor air

Indoor air concentrations of fifteen volatile per- and polyfluorinated compounds (PFCs) (five fluorotelomer alcohols (FTOHs), three fluorotelomer acrylates (FTAs), three perfluorinated sulfonamido ethanols (FASEs), and three perfluorinated sulfonamides (FASAs)) were determined in residential and nonresidential indoor air environments. Air samples were taken with passive samplers, consisting of XAD-4 impregnated polyurethane foam (PUF) disks in steel housings. Impregnated PUF disks were extracted by fluidized bed extraction (FBE) using methyl-tert-butyl ether/acetone (1:1) and analyzed by gas chromatography-mass spectrometry. Total PFC indoor air concentrations ranged from 8.2 to 458 ng m(-3). Individual PFC concentrations were between 42 pg m(-3) (6:2 FTA) and 209 ng m(-3) (8:2 FTOH). Concentrations of total FTOHs, FTAs, and FASAs + FASEs ranged from 0.2 to 152 ng m(-3) (FTAs), from 3.3 to 307 ng m(-3) (FTOHs), and from 4.4 to 148 ng m(-3) (FASAs + FASEs). Most elevated individual, group, and total PFC concentrations were detected in two stores selling outdoor equipment, one furniture shop, and one carpet shop. Indoor air concentrations were several orders of magnitude higher than published outdoor air concentrations indicating indoor air environments as sources for PFCs to the atmosphere. Concentrations were used to estimate human exposure to investigated PFCs.     

Polyphenol oxidase activity and implications on the quality of intermediate moisture and dried apples

This study aimed at investigating the water activity threshold for the polyphenol oxidase activity in Golden Delicious apple. Freeze-dried powders obtained from blanched and unblanched apples were equilibrated and stored at four water activity levels, ranging from 0.11 to 0.56, at 20 and 40 °C, to differentiate between nonenzymatic and enzymatic browning. The contents of hydroxycinnamic acids, phloridzin, catechin, epicatechin, polymeric flavan 3-ols, and 5-hydroxymethylfurfural, the antioxidant activity values, and the Hunter colorimetric parameters of apple products were analyzed. Results showed that no polyphenol oxidase activity occurred in unblanched dehydrated apples stored at water activity levels between 0.11 and 0.32. In this water activity range, blanching pre-treatment accelerated the Maillard reaction in the products stored at 40 °C, as observed from both higher 5-hydroxymethylfurfural formation and more intense red color development in blanched apples with respect to the unblanched ones. At the water activity level of 0.56, both increased redness and higher antioxidant degradation were observed in the unblanched apples with respect to the blanched apples, indicating that the threshold water activity for polyphenol oxidase was in the range 0.32–0.56. Among apple antioxidants, epicatechin was mostly affected by polyphenol oxidase activity, either by direct oxidation or by a coupled oxidation mechanism. Therefore, “mild” pre-heating treatments or no pre-treatments could be proposed when the apple is to be stored and used at water activity ≤0.32, whereas blanching should be applied for intermediate moisture apples or in food applications where moisture transfer from other ingredients could bring apples above this critical water activity level.     

A three-state model for DNA protein-coding regions

It is known that the protein-coding regions of DNA are usually characterized by a three-base periodicity. In this paper, we exploit this property, studying a DNA model based on three deterministic states, where each state implements a finite-context model. The experimental results obtained confirm the appropriateness of the proposed approach, showing compression gains in relation to the single finite-context model counterpart. Additionally, and potentially more interesting than the compression gain on its own, is the observation that the entropy associated to each of the three base positions of a codon differs and that this variation is not the same among the organisms analyzed.     

Interzonal air and moisture transport through large horizontal openings in a full-scale two-story test-hut: Part 1 – Experimental study

Moisture transport by convection through large horizontal openings in dwellings, such as staircases, could have significant impact on the level, variation and distribution of humidity in each zone of dwellings. Yet, most studies and simulation tools of heat, air and moisture transport in buildings do not consider nor properly model this phenomenon; the lack of experimental data is one of the main causes. The aim of this experimental investigation was to study the air and moisture transport through a horizontal opening in a full-scale two-story test-hut. This study extended the cases with buoyancy-driven flows that have been studied by a handful of existing investigations, to the cases of combined buoyancy airflows and mechanical ventilation and cases with warmer upper room than the lower rooms. The main investigated parameters were different ventilation strategies, ventilation rates, and temperature differences between the lower and upper rooms. In total, 20 cases were tested. Measurements of temperature, relative humidity and air velocity were carried out within both rooms and across the horizontal opening. The air and moisture exchange through the horizontal openings are investigated based on two quantities representing the phenomenon: (i) steady-state difference between the average humidity ratios of the two rooms at the end of the moisture generation period, and (ii) mass airflow rates through the opening. The results show that interzonal air and moisture exchanges through the horizontal openings are strongly linked to the temperature difference between the two rooms, and the mechanical ventilation significantly restricts the interzonal airflows in comparison with cases without mechanical ventilation.