Salmonella Ealing Infections Associated With Consumption of Infant Dried Milk

Rowe, B.; Hutchinson, D. N.; Gilbert, R. J.; Hales, B.H.; Begg, Norman; Dawkins, H. C.; Jacob, Megan E.; Rae, F.A.; Jepson, Mark A.

doi:10.1016/s0140-6736(87)91384-5

Cited by 137 publications

(62 citation statements)

References 8 publications

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“…Powdered infant formula also has been associated with outbreaks of illness due to Citrobacter and multiple Salmonella serotypes (13,(34)(35)(36)(37)(38). The degree to which E. sakazakii is a marker for a range of neonatal infections possibly related to powdered infant formula remains to be defined.…”

Section: Discussionmentioning

confidence: 99%

InvasiveEnterobacter sakazakiiDisease in Infants

Bowen¹,

Braden²

2006

Emerg. Infect. Dis.

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Section: Discussionmentioning

confidence: 99%

InvasiveEnterobacter sakazakiiDisease in Infants

Bowen¹,

Braden²

2006

Emerg. Infect. Dis.

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“…The presence of Salmonella cells in low-a w foods raises specific issues for food safety. Outbreak investigations indicate that only a very few Salmonella cells may be required to cause disease when consumed in low-a w foods (22,53). In addition, it is widely believed that cells suspended at lower a w during thermal inactivation are more heat tolerant than those suspended at a higher a w (6,14,19,21,38,58).…”

mentioning

confidence: 99%

Effect of Challenge Temperature and Solute Type on Heat Tolerance of Salmonella Serovars at Low Water Activity

Mattick

Jørgensen

Wang³

et al. 2001

Appl Environ Microbiol

135

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Salmonella spp. are reported to have an increased heat tolerance at low water activity (a w ; measured by relative vapor pressure [rvp]), achieved either by drying or by incorporating solutes. Much of the published data, however, cover only a narrow treatment range and have been analyzed by assuming first-order death kinetics. In this study, the death of Salmonella enterica serovar Typhimurium DT104 when exposed to 54 combinations of temperature (55 to 80°C) and a w (rvp 0.65 to 0.90, reduced using glucose-fructose) was investigated. The Weibull model (LogS ‫؍‬ ؊bt n ) was used to describe microbial inactivation, and surface response models were developed to predict death rates for serovar Typhimurium at all points within the design surface. The models were evaluated with data generated by using six different Salmonella strains in place of serovar Typhimurium DT104 strain 30, two different solutes in place of glucose-fructose to reduce a w , or six low-a w foods artificially contaminated with Salmonella in place of the sugar broths. The data demonstrate that, at temperatures of >70°C, Salmonella cells at low a w were more heat tolerant than those at a higher a w but below 65°C the reverse was true. The same patterns were generated when sucrose (rvp 0.80 compared with 0.90) or NaCl (0.75 compared with 0.90) was used to reduce a w , but the extent of the protection afforded varied with solute type. The predictions of thermal death rates in the low-a w foods were usually fail-safe, but the few exceptions highlight the importance of validating models with specific foods that may have additional factors affecting survival.

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“…For example, S. enterica serovar Napoli and S. enterica serovar Agona have caused international food poisoning outbreaks associated with low-a w chocolate (12,15) and a low a w -crisp type of snack, respectively (3,21,35). In addition, it has been reported that the infectious dose of Salmonella cells is reduced (e.g., 10 to 100 cells) when the organism is present in low-a w foods (15,32), possibly due to acid tolerance that occurs after sublethal osmotic stress, which has increased concern over the survival of the bacteria under these conditions. For these reasons it is important to continue to assess safety when either food composition or processing changes and to assess the ability of emerging pathogens, such as S. enterica serovar Typhimurium DT104, to survive at low a w .…”

mentioning

confidence: 99%

Survival and Filamentation of Salmonella enterica Serovar Enteritidis PT4 and Salmonella enterica Serovar Typhimurium DT104 at Low Water Activity

Mattick

Jørgensen

Legan³

et al. 2000

Appl Environ Microbiol

133

112

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In this study we investigated the long-term survival of and morphological changes in Salmonella strains at low water activity (a w ). Salmonella enterica serovar Enteritidis PT4 and Salmonella enterica serovar Typhimurium DT104 survived at low a w for long periods, but minimum humectant concentrations of 8% NaCl (a w , 0.95), 96% sucrose (a w , 0.94), and 32% glycerol (a w , 0.92) were bactericidal under most conditions. Salmonella rpoS mutants were usually more sensitive to bactericidal levels of NaCl, sucrose, and glycerol. At a lethal a w , incubation at 37°C resulted in more rapid loss of viability than incubation at 21°C. At a w values of 0.93 to 0.98, strains of S. enterica serovar Enteritidis and S. enterica serovar Typhimurium formed filaments, some of which were at least 200 m long. Filamentation was independent of rpoS expression. When the preparations were returned to high-a w conditions, the filaments formed septa, and division was complete within approximately 2 to 3 h. The variable survival of Salmonella strains at low a w highlights the importance of strain choice when researchers produce modelling data to simulate worst-case scenarios or conduct risk assessments based on laboratory data. The continued increase in Salmonella biomass at low a w (without a concomitant increase in microbial count) would not have been detected by traditional microbiological enumeration tests if the tests had been performed immediately after low-a w storage. If Salmonella strains form filaments in food products that have low a w values (0.92 to 0.98), there are significant implications for public health and for designing methods for microbiological monitoring.

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Salmonella Ealing Infections Associated With Consumption of Infant Dried Milk

Cited by 137 publications

References 8 publications

InvasiveEnterobacter sakazakiiDisease in Infants

InvasiveEnterobacter sakazakiiDisease in Infants

Effect of Challenge Temperature and Solute Type on Heat Tolerance of Salmonella Serovars at Low Water Activity

Survival and Filamentation of Salmonella enterica Serovar Enteritidis PT4 and Salmonella enterica Serovar Typhimurium DT104 at Low Water Activity

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