Listeria monocytogenes in Milk Products

peer-reviewedMilk and milk products are frequently identified as vectors for transmission of Listeria monocytogenes. Milk can be contaminated at farm level either by indirect external contamination from the farm environment or less frequently by direct contamination of the milk from infection in the animal. Pasteurisation of milk will kill L. monocytogenes, but post-pasteurisation contamination, consumption of unpasteurised milk and manufacture of unpasteurised milk products can lead to milk being the cause of outbreaks of listeriosis. Therefore, there is a concern that L. monocytogenes in milk could lead to a public health risk. To protect against this risk, there is a need for awareness surrounding the issues, hygienic practices to reduce the risk and adequate sampling and analysis to verify that the risk is controlled. This review will highlight the issues surrounding L. monocytogenes in milk and milk products, including possible control measures. It will therefore create awareness about L. monocytogenes, contributing to protection of public health

Air quality impacts of liquefied natural gas in the South Coast Air Basin of California

The effects of liquefied natural gas (LNG) on pollutant emission inventories and air quality in the South Coast Air Basin (SoCAB) of California are evaluated using recent appliance emissions measurements by Lawrence Berkeley National Laboratory and the Southern California Gas Company (SoCalGas), and use of a state-of-the-art air quality model. Pollutant emissions can be impacted by LNG operation because of differences in composition and physical properties including the Wobbe index, a measure of energy delivery rate. Various LNG distribution scenarios are evaluated to determine the potential impacts of LNG. Projected penetration of LNG in the SoCalGas pipeline network in SoCAB is expected to be limited, which could cause increases in overall (area-wide) emissions of nitrogen oxides that are smaller than 0.05%. Based on the photochemical state of the South Coast Air Basin of California, any increase in NOx is expected to cause an increase in the highest local ozone concentrations, which is observed in model results. However, the magnitude of NOx emissions increases due to LNG use is determined to be within the uncertainty range of natural gas combustion sources and would not be discernible with the existing monitoring network

Development and assessment of a physics-based simulation model to investigate residential PM2.5 infiltration across the US housing stock

The Lawrence Berkeley National Laboratory Population Impact Assessment Modeling Framework (PIAMF) was expanded to enable determination of indoor PM concentrations and exposures in a set of 50,000 homes representing the US housing stock. A mass-balance model is used to calculate time-dependent pollutant concentrations within each home. The model includes size- and species-dependent removal mechanisms. The particle model was applied to the housing samples of the Relationship of Indoor, Outdoor, and Personal Air (RIOPA) and The Detroit Exposure and Aerosol Research Study (DEARS) studies to compare model- and measurement-based estimates of indoor PM of outdoor origin. Model-derived distributions of infiltration factors (ratio of indoor PM of outdoor origin to outdoor PM ) are compared to measurement-based distributions obtained in studies conducted in 11 US cities. 2.5 2.5 2.5 2.

Indoor particle counts during Asian dust events under everyday conditions at an apartment in Japan

[Objective]Asian dust storms originating from arid regions of Mongolia and China are a well-known springtime phenomenon throughout East Asia. Evidence is increasing for the adverse health effects caused by airborne desert dust inhalation. Given that people spend approximately 90 % of their time indoors, indoor air quality is a significant concern. The present study aimed to examine the influence of outdoor particulate matter (PM) levels on indoor PM levels during Asian dust events under everyday conditions. [Methods]We simultaneously monitored counts of particles larger than 0.3, 0.5, 1, 2, and 5 μm using two direct-reading instruments (KC-01D1 airborne particle counter; Rion), one placed in an apartment room and another on the veranda, under everyday conditions before and during an Asian dust event. We also examined how indoor particle counts were affected by opening a window, crawling, and air purifier use. [Results]An Asian dust event on 24 April 2012 caused 50- and 20-fold increases in PM counts in outdoor and indoor air, respectively. A window open for 10 min resulted in a rapid increase of indoor PM counts up to 70 % of outside levels that did not return to baseline levels after 3 h. An air purifier rapidly reduced PM counts for all particle sizes measured. [Conclusions]It is important to account for occupant behavior, such as window-opening and air purifier use, when estimating residential exposure to particulate matter