The Influence of Rehydration on the Viability of Dried Micro-Organisms

Leach, R. H.; Scott, W. J.

doi:10.1099/00221287-21-2-295

Cited by 56 publications

(26 citation statements)

References 22 publications

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“…The temperature during rehydration was found to influence microbial survival, with 37 inferior to 22, 11, or 0°C (Leach and Scott 1959). A rehydration temperature of 30°C was selected for recovering freeze-dried samples (Valdez et al 1985;Kearney et al 1990).…”

Section: Introductionmentioning

confidence: 99%

“…s -' . mg freeze-dried microorganisms -' (Leach and Scott 1959 dried sample in concentrated glucose solution, then slowly diluting with buffer (Record et al 1962), or alternatively by rehumidifying before sampling (Strange and Cox 1976). With cells immobilized in alginate beads, the rehydration rate is controlled by the diffusion properties of the alginate bead, and thus upshock is avoided (Kearney et al 1990).…”

Section: Introductionmentioning

confidence: 99%

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Slow rehydration improves the recovery of dried bacterial populations

Kosanke¹,

Osburn²,

Shuppe³

et al. 1992

Can. J. Microbiol.

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Slow rehydration of bacteria from dried inoculant formulations provided higher viable counts than did rapid rehydration. Estimates were higher when clay and peat powder formulations of Rhizobium meliloti, Rhizobium leguminosarum biovar trifolii, and Pseudomonas putida, with water activities between 0.280 and 0.650, were slowly rehydrated to water activities of approximately 0.992 before continuing the dilution plating sequence. Rhizobium meliloti populations averaged 6.8 x 10(8) cfu/g and 1328 cfu/alfalfa seed greater when slowly rehydrated from bulk powder and preinoculated seeds, respectively. Bulk powder samples were slowly rehydrated to 0.992 water activity by the gradual addition of diluent, followed by a 10-min period for moisture equilibration. Preinoculated seed samples were placed in an environmental chamber at 24 degrees C with relative humidity greater than 80% for 1 h to allow moisture absorption. "Upshock," osmotic cellular stresses that occur during rehydration, was reduced when dried microbial formulations were slowly rehydrated and equilibrated before becoming fully hydrated in the dilution plating sequence. These procedures may also be applicable when estimating total viable bacterial populations from dried soil or other dry formulations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Slow rehydration improves the recovery of dried bacterial populations

Kosanke¹,

Osburn²,

Shuppe³

et al. 1992

Can. J. Microbiol.

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“…The occurrence of instability zones may explain reports (Leach & Scott, 1959;Silver, 1963) of the influence of rehydration rate, since as well as the possibility of spheroplast formation (Record, Taylor & Miller, 1962;Cox, 1963), the opportunity for an organism to be exposed to a lethal R H range will depend upon the rate and extent of rehydration and of dehydration. For appreciable decay to occur at high RH, maintenance for several minutes at a critical RH seems necessary; but if the mechanism of loss of viability with regard to time is such that the minima widen, rather than increase in intensity, then complete loss of viability may be rapidly achieved at certain super-critical R H values.…”

Section: The Action Of Protecting Agentsmentioning

confidence: 99%

The Survival of Escherichia coli sprayed into Air and into Nitrogen from Distilled Water and from Solutions of Protecting Agents, as a Function of Relative Humidity

Cox

1966

Journal of General Microbiology

103

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SUMMARYThe survival in air as a function of relative humidity (RH) and aerosol age is reported for Escherichia coli (strains B and Jepp) and for Serratia marcescens (strain U K 8 ) sprayed from suspensions in distilled water and in solutions of dextran and of raffinose. The survival in nitrogen ( > 99.9 yo) of E . coli (strains B, Jepp and commune) is given as a function of RH, when sprayed from suspension in distilled water and in raffinose solution. The results show that E . coli in the aerosol was subject to at least three stresses, an air stress, an RH stress, and a collection stress. The air stress accounted for loss of viability at low RH and the RH stress occured a t high RH and is expressed as RH ranges in which E . coli rapidly lost viability. The survival, especially a t high RH, depended upon the composition of the collecting fluid. At high RH a range of RH was found in which the bacteria were unstable when collected in phosphate buffer. Addition of raffinose (chosen as a typical protecting agent) to the spray fluid and the addition of M-sucrose to the collecting fluid eliminated the instability for E . coli (commune) and decreased it for the other two strains.

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“…In a state of dry anabiosis, metabolic processes within the living spore are slowed or halted during storage at reduced moisture. Survival of microorganisms during storage is affected by a variety of factors including the drying process (Antheunisse & ArkestelinDilksman 1979), storage conditions (Mary et al 1985), and the rehydration process (Leach & Scott 1959). In addition, compatible solutes such as sugars and polyols are added to the formulation to maintain osmotic equilibrium (Brown 1976), and protect enzymes and membranes (Lippert & Galinski 1992).…”

Section: Introductionmentioning

confidence: 99%

Effect of conditions and protectants on the survival ofPenicillium bilaiaeduring storage

Friesen

Holloway²,

Hill

et al. 2006

Biocontrol Science and Technology

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Penicillium bilaiae is a fungal microorganism used to promote soil-bound phosphorous uptake in several crop species such as wheat, canola, and pulse crops. In this study, an air-dried granular starch-based form of the inoculant was studied for improved longevity. Experiments were performed to determine optimal water activity, packaging atmosphere, and the effects of several protective chemicals. Viable spore fractions were measured at 1, 3, and 6 months. Longevity of the microorganism was found to suffer at intermediate values of water activity and with the addition of glycerol. However, skim milk powder, sucrose, MSG, and proprietary PBX3000 were found to improve survival, with a maximum survival fraction of 15% at 6 months using the best formulation. Cell concentration was not found to influence shelf-life. High viability loss during storage in a nitrogen environment resulted in less than 1% survival.

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The Influence of Rehydration on the Viability of Dried Micro-Organisms

Cited by 56 publications

References 22 publications

Slow rehydration improves the recovery of dried bacterial populations

Slow rehydration improves the recovery of dried bacterial populations

The Survival of Escherichia coli sprayed into Air and into Nitrogen from Distilled Water and from Solutions of Protecting Agents, as a Function of Relative Humidity

Effect of conditions and protectants on the survival ofPenicillium bilaiaeduring storage

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