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A multi-state outbreak of Salmonella enterica serovar Saintpaul infection occurred in Australia during October 2006. A case-control study conducted in three affected jurisdictions, New South Wales, Victoria and Australian Capital Territory, included 36 cases with the outbreak-specific strain of S. Saintpaul identified by multiple locus variable-number tandem repeat analysis (MLVA) in a faecal specimen and 106 controls. Consumption of cantaloupe (rockmelon) was strongly associated with illness (adjusted OR 23.9 95%, 95% CI 5.1-112.4). S. Saintpaul, with the outbreak MLVA profile, was detected on the skin of two cantaloupes obtained from an implicated retailer. Trace-back investigations did not identify the specific source of the outbreak strain of S. Saintpaul, but multiple Salmonella spp. were detected in environmental samples from farms and packing plants investigated during the trace-back operation. Cantaloupe production and processing practices pose a potential public health threat requiring regulatory and community educational interventions. [ABSTRACT FROM AUTHOR]

We identified an increase in the number of cases of Salmonella Typhimurium phage type 197 in New South Wales in February 2005. Cases were predominantly of Lebanese descent. To identify risk factors for illness, we conducted an unmatched case-control study including 12 cases and 21 controls. Eight of 12 cases (67%) and no controls reported eating lambs' liver (OR incalculable, P<0.05), and seven of nine cases (78%) and one of 21 controls (5%) reported eating fresh fish (OR 70.0, P<0.05). Among participants who did not eat liver, there was a strong association between eating fish and illness (OR 60.0, P<0.05). The fish was from divergent sources. Five cases had bought the liver from two different butcher's shops, which obtained the lambs' liver from a single abattoir. Consumption of liver is a risk for salmonellosis. Traditional dishes may place some ethnic groups at increased risk of foodborne disease. [ABSTRACT FROM AUTHOR]

During May 2015, an increase in Salmonella Agona cases was reported from western Sydney, Australia. We examine the public health actions used to investigate and control this increase. A descriptive case-series investigation was conducted. Six outbreak cases were identified; all had consumed cooked tuna sushi rolls purchased within a western Sydney shopping complex. Onset of illness for outbreak cases occurred between 7 April and 24 May 2015. Salmonella was isolated from food samples collected from the implicated premise and a prohibition order issued. No further cases were identified following this action. Whole genome sequence (WGS) analysis was performed on isolates recovered during this investigation, with additional S. Agona isolates from sporadic-clinical cases and routine food sampling in New South Wales, January to July 2015. Clinical isolates of outbreak cases were indistinguishable from food isolates collected from the implicated sushi outlet. Five additional clinical isolates not originally considered to be linked to the outbreak were genomically similar to outbreak isolates, indicating the point-source contamination may have started before routine surveillance identified an increase. This investigation demonstrated the value of genomics-guided public health action, where near real-time WGS enhanced the resolution of the epidemiological investigation.

Outbreaks of Escherichia coli infections linked to fermented meats have prompted much research into the kinetics of E. coli inactivation during fermented meat manufacture. A meta-analysis of data from 44 independent studies was undertaken that allowed the relative influences of pH, water activity (a(w)), and temperature on E. coli survival during fermented meat processing to be investigated. Data were reevaluated to determine rates of inactivation, providing 484 rate data points with various pH (2.8 to 6.14), a(w) (0.75 to 0.986), and temperature (-20 to 66 degrees C) values, product formulations, and E. coli strains and serotypes. When the data were presented as an Arrhenius model, temperature (0 to 47 degrees C) accounted for 61% of the variance in the ln(inactivation rate) data. In contrast, the pH or a(w) measured accounted for less than 8% of variability in the data, and the effects of other pH- and a(w)-based variables (i.e., total decrease and rates of reduction of those factors) were largely dependent on the temperature of the process. These findings indicate that although temperatures typically used in fermented meat manufacture are not lethal to E. coli per se, when other factors prevent E. coli growth (e.g., low pH and a(w)), the rate of inactivation of E. coli is dominated by temperature. In contrast, inactivation rates at temperatures above approximately 50 degrees C were characterized by smaller z values than those at 0 to 47 degrees C, suggesting that the mechanisms of inactivation are different in these temperature ranges. The Arrhenius model developed can be used to improve product safety by quantifying the effects of changes in temperature and/or time on E. coli inactivation during fermented meat manufacture.

Salmonellosis is a bacterial disease that causes acute gastroenteritis, with sudden onset of headache, abdominal pain, diarrhoea, nausea and sometimes vomiting. Infection is often associated with the consumption of foods prepared using raw eggs. During July to August 2008 an outbreak at an aged care facility (ACF) in New South Wales was confirmed as Salmonella Typhimurium phage type 44 (Stm 44) in eight of 45 residents. Two additional probable cases also occurred. Cases were located in each unit of the ACF and for 5 cases, onset of diarrhoea was between 45 to 64 hours (median of 46 hours) after consumption of a dessert containing raw eggs. Onset for 5 further cases occurred up to 9 days after this meal. Eggs were supplied to the ACF from a local farm. Stm 44 was detected on an egg in an unopened box at the ACF from this supplier. The raw-egg dessert was epidemiologically implicated as the likely source of the Salmonella and delayed onset cases may have resulted from ingestion of a smaller dose of Salmonella, or ongoing transmission through cross-contamination of kitchen machinery or surfaces. This outbreak demonstrates that inadequate cooking of eggs continues to pose a risk for Salmonella infection in settings with vulnerable populations. The findings of the investigation provide support for the importance of food safety regulations and demand further advocacy for measures to reduce the risks associated with the distribution, storage and preparation of shell eggs.

The destruction of Escherichia coli M23 OR.H- using lethal water activity levels and nonlethal temperatures was investigated. Death rates were measured for a combination of four growth-permissible temperatures (15 degrees C, 25 degrees C, 40 degrees C and 45 degrees C) and four distinctly lethal water activities (0.75, 0.83, 0.88 and 0.90). In addition, death rates were measured at two temperatures (4 degrees C and 50 degrees C) outside the growth range of E. coli. Death rate increased both at higher temperature or lower water activity. Inactivation curves resulting from exposure of E. coli to osmotic stress were biphasic. The initial rate of death was followed by a slower second phase decline, or "tailing" effect. Addition of chloramphenicol to the suspending medium reduced the tailing effect and suggested that tailing was caused by de novo protein synthesis.

The water activity and pH ranges for growth of Glaciecola punicea (a psychrophile) were extended when this organism was grown at suboptimal rather than optimal temperatures. No such extension was observed for Gelidibacter sp. strain IC158 (a psychrotolerant bacterium) at analogous temperatures. Salinity and pH may be primary physicochemical parameters controlling bacterial community development in sea ice.