Survival and Recovery of Thermally Stressed Yeast in Orange Juice

Graumlich, T. R.

doi:10.1111/j.1365-2621.1981.tb04186.x

Cited by 9 publications

(3 citation statements)

References 7 publications

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“…While an abundance of studies have been conducted to determine the influence of growth, heat treatment and recovery environment (e.g. Hansen and Riemann, 1963;Corry, 1976a;1976b;Tomlins and Ordal, 1976;Graumlich and Stevenson, 1978;Graumlich, 1981;Put and De Jong, 1982;Beuchat, 1981;Splittstoesser et al, 1986;Torreggiani and Toledo, 1986), very little was known about the genetics, expression, control and regulation of true heat resistance of microorganisms. Proper measurement was lacking and definitions of heat resistance varied depending on terms of food safety and technology or on scientists seeking basic explanations for differences in thermal behavior of microorganisms.…”

Section: Discussionmentioning

confidence: 99%

Thermal Inactivation Kinetics of Food‐borne Yeasts

Török¹,

King²

1991

Journal of Food Science

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The thermal inactivation kinetics of three food-borne yeasts from heattreated products-two Sacc. cerevisiae and one Zygosacc. roux&have been determined. Thermal treatment and evaluation of results were carried out according to the dynamic heat destruction method. Results for 0.5% (whv) glucose as heating medium expressed in Ds5 values were 1.05, 2.67 and 0.16 min, respectively. The respective z values were 4.00, 6.23 and 5.55"C. The apparent activation energy for heat destruction calculated from the Arrhenius plot for the three yeasts were 5.05*105, 3.61*105 and 3.60*105 Jmol-'. Applying Eyring's theory of absolute reaction rates for thermal destruction, values for enthalpy and entropy of activation could be calculated.

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Section: Discussionmentioning

confidence: 99%

Thermal Inactivation Kinetics of Food‐borne Yeasts

Török¹,

King²

1991

Journal of Food Science

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“…The recognition of sublethally-impaired cells is essential for the accurate assessment of the quality of foods. Most observations on injury and recovery of yeasts have been made on cells subjected to heat stress (Graumlich 1981 ;Stecchini and Beuchat 1985;Golden and Beuchat 1990); less information is available about freeze-injured yeasts (Beuchat and Nail 1985 ;.…”

Section: Introductionmentioning

confidence: 99%

Comparison of conductimetric and traditional plating techniques for detecting yeasts in fruit juices

Deák

Beuchat

1993

Journal of Applied Bacteriology

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Frozen fruit juice concentrates containing an average microbial population of loglo 1-54 cfu ml-were examined by traditional plating techniques and direct and indirect conductimetry. T h e initial populations in diluted (1 : 4) concentrates increased to an average of loglo 3.82 cfu mlK during incubation at 25°C for 24 h. Incubation before plating and subjecting to conductimetric tests also facilitated the resuscitation of cells that may have been freeze-injured. Yeasts were recovered in equal numbers on acidified ( p H 3.5) potato dextrose agar and dichloran rose bengal chloramphenicol agar ( p H 5.6). Yeasts and bacteria were recovered on orange serum agar. Detection times determined by indirect conductimetry correlated fairly well (r = -0.73) with populations (cfu mi-') detected on traditional plating media. Populations in diluted concentrates which were not incubated before examination were detected conductimetrically in an average of 48.9 h, whereas detection times for diluted concentrates incubated for 24 h at 25°C before testing were reduced to an average of 14.1 h. Examination by conventional (direct) conductimetry required an additional 10-20 h to reach changes in conductance of 5 $3 h-'. ' 'Permanent address

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“…Yeast cells stressed by high temperature require optimum recovery conditions to resuscitate (8,21). The extent and nature of injury caused by reduced temperature can vary depending upon the conditions under which the cells have been grown and the physical and chemical characteristics of the medium in which the cells are suspended.…”

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confidence: 99%

Performance of Selective Media for Enumerating Zygosaccharomyces bailii in Acidic Foods and Beverages

Makdesi

Beuchat

1996

Journal of Food Protection

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A study was undertaken to evaluate the performance of yeast-malt extract agar (YMA) (control medium) and three selective media, acidified YMA (AYMA), acidified tryptone-glucose-yeast extract agar (TGYA), and Zygosaccharomyces bailii selective agar (ZBA), for detecting and enumerating nine strains of Z. bailii grown in six commercial food products with aw and pH values ranging from 0.82 to 0.99 and 2.99 to 6.47, respectively. These media were also evaluated for their suitability for enumerating two strains of Z. bailii grown in blueberry syrup containing 0, 300, and 600 μg of sodium benzoate ml−1 and subsequently stored at 1 and −19°C. The nonselective enumeration medium (YMA) supported significantly (P ≤ 0.05) higher recovery of all strains of Z. bailii from the six food products compared to the three selective media; TGYA was the best selective medium, followed by ZBA. The performance of the selective media was dependent on the strain of Z. bailii and the food type. Recovery of cells of Z. bailii from blueberry syrup before storage or after storage at 1 or −19°C was equivalent on YMA, TGYA, and ZBA but inferior on AYMA, regardless of the benzoate concentration in the syrup in which the cells had grown. Cells in blueberry syrup held at −19°C exhibited a higher sensitivity to the acidic environment imposed by selective media compared to cells held at 1°C. Sensitivity to selective media was more apparent in cells grown in syrup containing no sodium benzoate compared to cells grown in syrup containing 300 or 600 μg of sodium benzoate ml−1. It is recommended that TGYA be used for enumerating Z. bailii in acidic foods with reduced aw, regardless of the presence of sodium benzoate in these foods or the reduced temperature at which they are held before being analyzed.

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Survival and Recovery of Thermally Stressed Yeast in Orange Juice

Cited by 9 publications

References 7 publications

Thermal Inactivation Kinetics of Food‐borne Yeasts

Thermal Inactivation Kinetics of Food‐borne Yeasts

Comparison of conductimetric and traditional plating techniques for detecting yeasts in fruit juices

Performance of Selective Media for Enumerating Zygosaccharomyces bailii in Acidic Foods and Beverages

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