Injury and Repair of Several Salmonella Serotypes After Freezing and Thawing in Milk Solids1

Janssen, D. W.; Busta, F. F.

doi:10.4315/0022-2747-36.10.520

Cited by 9 publications

(2 citation statements)

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“…Several researchers have reported the reduced recovery of stressed Salmonella on selective agars ( Janssen & Busta 1973; Strantz & Zottola 1993). As XLD agar is a selective agar, it might not adequately support resuscitation and eventual colony formation by citric acid‐injured cells.…”

Section: Resultsmentioning

confidence: 99%

The fate of Salmonella enteritidis PT4 in home‐made mayonnaise prepared with citric acid

Xiong

Xie

Edmondson

1999

Letters in Applied Microbiology

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The fate of Salmonella enteritidis PT4 in home‐made mayonnaise prepared with citric acid solution (citric acid concentration of Ð4·98% (w/v)) was investigated. It was found that pH of mayonnaise is closely related to the ratio of egg yolk to citric acid, and the inactivation rate of the micro‐organisms increases as the ratio decreases and/or incubation temperature increases. To achieve Salm. enteritidis PT4‐free home‐made mayonnaise prepared with pure lemon juice (citric acid concentration Ð5% (w/v)), it is recommended that the pH should be 3·30 or below, or, in practice, at least 20 ml pure lemon juice per fresh egg yolk should be used. For the use of 20–35 ml pure lemon juice per egg yolk, the product should be held at 22 °C or over for at least 72 h and for the use of over 35 ml pure lemon juice per egg yolk, for at least 48 h before consumption or refrigeration.

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Section: Resultsmentioning

confidence: 99%

The fate of Salmonella enteritidis PT4 in home‐made mayonnaise prepared with citric acid

Xiong

Xie

Edmondson

1999

Letters in Applied Microbiology

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“…Several solid plating media and selective agents were evaluated for their ability to enumerate normal and heat-stressed Y. enterocolitica cells. Various concentrations of the selective agents NaCl, BS, and sodium deoxycholate (Difco) were incorporated into BHI agar, TSA, TSA plus 0.5% yeast extract, xylose lysine agar base (Difco) with 1% peptone (38), and MacConkey agar (Difco). Of the selective media tested, TSA plus BS proved best for estimating stressed Y. enterocolitica 0: 17, 0:8, and 0:3 cells when heated at 47°C in 0.1 M P04 buffer, pH 7.0.…”

Section: Resultsmentioning

confidence: 99%

Thermal injury of Yersinia enterocolitica

Restaino¹,

Jeter²,

Hill³

1980

Appl Environ Microbiol

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Procedures were developed to evaluate thermal injury to three strains of Yersinia enterocolitica (serotypes 0:3, 0:8, and 0:17). Serotype 0:17 (atypical strain) was more sensitive to bile salts no. 3 (BS) and to sublethal heat treatment than the typical strains, 0:3 and 0:8. When the 0:3, 0:8, and 0:17 serotypes were thermally stressed in 0.1 M P04 buffer, pH 7.0, at 470C for 70, 60, and 12 mi, respectively, greater than 99% of the total viable cell population was injured. Injury was determined by the ability of cells to form colonies on brain heart infusion (BHI) agar, but not on Trypticase soy agar (TSA) plus 0.6% BS for serotypes 0:3 and 0:8 and TSA plus 0.16% BS for 0:17. Heat injury of serotype 0: 17 cells for 15 min in 0.1 M P04 buffer caused an approximate 1,000-fold reduction in cell numbers on selective media as compared with cells heated in pork infusion (PI), BHI broth, and 10% nonfat dry milk (NFDM). The extended lag and resuscitation period in BHI broth was 2.5 times greater for 0:17 cells injured in 0.1 M P04 than for cells injured in BHI or PI. The rate and extent of repair of Y. enterocolitica 0:17 cells in three recovery media were directly related to the heating menstruum used for injury. The use of metabolic inhibitors demonstrated that ribonucleic acid synthesis was required for repair, whereas deoxyribonucleic, cell wall, and protein synthesis were not necessary for recovery of 0:17 cells injured in 0.1 M P04 buffer, BHI, or PI. Inhibition of respiration by 2,4-dinitrophenol slowed repair only for 0:17 cells injured in 0.1 M P04 buffer, not for cells injured in PI or BHI. Yersinia enterocolitica and Y. enterocoliticalike organisms (atypical strains) have been isolated from a wide variety of foods as well as from environmental sources. In an extensive European survey, Leistner et al. (43) identified Y. enterocolitica in chicken meat, pork, and beef. Strains have been isolated from vacuum-packaged beef, lamb, and dark firm meat (pH 2 6.5) held under refrigeration (20, 26, 54), raw and pasteurized milk (32, 52), cheeses (51), mussels, ice cream, bananas, fish, ham, and sausage (41). They have also been isolated from pond and well water (11), streams, lakes (28), and drinking water (39). Only one foodborne outbreak caused by Y. enterocolitica has been documented (14), although food sources were implicated in other outbreaks (15, 29, 59). In 1976, an illness occurred among school children in Oneida County, New York (5). Chocolate milk was determined to be the common vector of transmission. Serotype 0:8 was isolated from an unopened carton of the milk and from the hospitalized children. Thirty-three children were hospitalized for suspected appendicitis, and 13 appendectomies were performed. Many treatments used in food processing and combinations of treatments may induce suble-thal damage to cells or spores (12). In addition, the production of bacterial end products such as organic acids in foods may cause sensitive bacterial cells to become stressed or injured. Therefore, unprocessed as well as pr...

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1980

Microbial Ecology of Foods

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Injury and Repair of Several Salmonella Serotypes After Freezing and Thawing in Milk Solids1

Cited by 9 publications

References 0 publications

The fate of Salmonella enteritidis PT4 in home‐made mayonnaise prepared with citric acid

The fate of Salmonella enteritidis PT4 in home‐made mayonnaise prepared with citric acid

Thermal injury of Yersinia enterocolitica

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