Chocolate bars contaminated with Salmonella napoli: an infectivity study.

Greenwood, M.; Hooper, W. L.

doi:10.1136/bmj.286.6375.1394

Cited by 93 publications

(51 citation statements)

References 4 publications

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“…This affects primarily the spoilage stability of the products at the lower end of this a w range, but pathogens, including Salmonella spp., have caused illness following survival in foods at the higher end. 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.…”

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confidence: 99%

“…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 .…”

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confidence: 99%

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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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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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“…Salmonella strains had decreased by 0.5 to 1 log CFU/mL of juice after seven days (Figure 6). Nonetheless, survival of even a small concentration of Salmonella under refrigeration poses a serious health hazard to consumers since salmonellosis outbreaks have been reported as originating in different foods at low pathogen concentrations (Greenwood and Hopper, 1983).…”

Section: Resultsmentioning

confidence: 99%

The behavior of Salmonella Typhimurium, Salmonella Typhi, Salmonella Agona and Salmonella Montevideo in raw carrot and in fresh unpasteurized carrot juice

Palma-Quiroz¹,

Gómez‐Aldapa²,

Torres-Vitela³

et al. 2013

Afr. J. Microbiol. Res.

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The behavior of Salmonella Typhimurium, Salmonella Typhi, Salmonella Agona and Salmonella Montevideo in raw carrot at 30 ± 1 and 3 ± 1°C and in unpasteurized carrot juice at 3 ± 1, 12 ± 1, 20 ± 1, 30 ± 1 and 37 ± 1°C was determined. Fresh juice was obtained from carrots in the laboratory. Raw carrots were collected from a market in Pachuca city, Hidalgo, Mexico. On whole carrots stored at 20 ± 1 or 3 ± 1°C, no growth was observed for Salmonella strains. After 15 days at 30 ± 2°C, Salmonella serotypes decreased from an initial inoculum level of approximately 6 log CFU to 3.4 log in all the carrots; and at 3 ± 1°C, they decreased from approximately 2.6 log CFU to 1.7 log. All Salmonella serotypes grew in carrot juice at 12 ± 1, 20 ± 1, 30 ± 1 and 37 ± 1°C, reaching counts of approximately 4.3, 6, 6.8 and 7.5 log CFU/mL, respectively after 24 h. At 3 ± 1°C, the Salmonella growth was inhibited at least for 7 days.

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“…Under refrigeration (3-5 °C), growth in the Salmonella serotypes and E. coli strains was inhibited ( Figure 4): bacterial concentration at 5 days was essentially similar to initial inocula levels. Nonetheless, survival of even a small concentration of E. coli and/or Salmonella under refrigeration poses a serious health hazard to consumers since salmonellosis outbreaks have been reported as originating in different foods at low pathogen concentrations (Greenwood and Hopper, 1983). In a separate study, we tested the growth behavior of the same four Salmonella serotypes and three E. coli strains at the same temperatures (25±2 and 3-5 °C) on whole and sliced jalapeño and serrano peppers, as well as in a blended chili pepper sauce .…”

Section: Interaction Of Salmonella With Foodsmentioning

confidence: 99%