EFFECTS OF FREEZING, FREEZE-DRYING, AND STORAGE IN THE FREEZE-DRIED AND FROZEN STATE ON VIABILITY OF ESCHERICHIA COLI CELLS

1961 ◽  
Vol 7 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Mary T. Clement
Keyword(s):  
Escherichia Coli ◽  
Freeze Drying ◽  
Storage Temperature ◽  
Stable State ◽  
Skim Milk ◽  
Escherichia Coli Cells ◽  
Freeze Dried ◽  
C 23 ◽  
Frozen State ◽  
Final Survival

Escherichia coli cells in concentrations of 2 × 109cells per ml were resistant to freezing at −78 °C and to low temperatures encountered during freeze-drying when suspended in distilled water, 7.5% glucose, 4.5% glycerol, skim milk, or serum but not when in saline. Survival immediately after freeze-drying varied with the drying interval and composition of the suspending medium and was highest (70–100%) in media containing 7.5% added glucose. Survival during storage in freeze-dried suspensions in serum containing 7.5% added glucose was inversely related to storage time and temperature; after 1 year at 32 °C, 21 °C, and 4 °C, survival was 0, 25%, and 80% respectively. When suspensions in water, glucose, glycerol, and serum were frozen directly and stored in the frozen state at −18 °C, −23 °C, and −40 °C, the cells showed a diminishing death rate and eventually attained a stable state. The final survival level varied with the composition of the suspending medium and the storage temperature. Glycerol provided most consistent protection (minimum survival 65%). Survival in water and glucose was inversely proportional to the storage temperature. Viability in water was higher than in glucose and was equal to glycerol in storage at −40 °C (80% after 2 years).

Freezing and freeze-drying

1975 ◽  
Vol 191 (1102) ◽  
pp. 9-19 ◽  
Keyword(s):  
Low Temperature ◽  
Freeze Drying ◽  
Storage Temperature ◽  
Research Work ◽  
High Water Content ◽  
Freezing Process ◽  
Neutral Atmosphere ◽  
Reduced Pressure ◽  
Freeze Dried ◽  
Frozen State

Most biological substances are unstable during storage owing to their high water content. This is why numerous attempts have been made over the last 100 years to prevent, by low temperature freezing, metabolic and biochemical degradations. The transformation of water into ice brings to an end all chemical reactions; however, it might also induce deleterious alterations into the delicate structure of many products. A brief review of the basic phenomena involved in the freezing process of biological substances helps to understand how the cooling cycles, storage temperature and subsequent rewarming have to be monitored in each individual case. Despite the fact that preservation in the frozen state offers wide possibilities, it is still difficult to apply in some instances, since it implies a continuous low temperature storage and transportation. This is why freeze-drying, or lyophilization, has been introduced. It is a two-step process in which the products to be preserved are deep frozen first, then dried by direct sublimation of the ice under reduced pressure. When completely dehydrated the substances can be stored almost indefinitely if kept in a dry, neutral atmosphere and in the dark. Fundamental aspects of the freeze-drying process will be discussed. Recent research work has shown that drying by sublimation from the frozen state can be performed with other systems than aqueous media. Solutions of lipophilic compounds, fats, phospholipids, steroids, in organic solvents can be ‘freeze-dried’ at low temperatures and high velocities. This particular technology opens new fields for the preservation of delicate materials of living origins.

scholarly journals Viability of L. casei during fermentation in soymilk and freeze-dried soymilk; effect of cryoprotectant, rehydration and storage temperature

2006 ◽  
Vol 52 ◽  
pp. 17-24
Author(s):  
Lela Acevska ◽  
Kristina Mladenovska ◽  
Tanja Petreska Ivanovska ◽  
Maja Jurhar Pavlova ◽  
Milena Petrovska ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Storage Temperature ◽  
Acid Stress ◽  
Titratable Acidity ◽  
Therapeutic Level ◽  
Freeze Dried ◽  
Different Temperatures ◽  
And Storage

Viability of L. casei during fermentation in soymilk and freeze-dried soymilk; effect of cryoprotectant, rehydration and storage temperature The aim of the work was to investigate the behaviour of L. casei and the effect of sorbitol on its viability during fermentation in soymilk drink. Values for pH, ranging from 6.82 to 3.42 in the soymilk drink without sorbitol and from 6.74 to 3.41 in the drink with sorbitol were noted during 72 h of fermentation at 25oC. The corresponding values for titratable acidity ranged from 0.071% to 0.758% and from 0.073% to 0.761%, respectively. Soymilk was found to support the growth of L. casei with improvement in viability for 0.24 log at the end of fermentation when sorbitol was added. Survival of L. casei and the effectiveness of sorbitol in improving viability during freeze-drying, subsequent rehydration and during a 5-week period of storage under different temperatures were also investigated. After freeze-drying, L. casei exhibited a survival percent of approximately 46%. Sorbitol improved the viability of L. casei by 0.51 log immediately after freeze-drying and by 1.30 log and 0.47 log during five weeks of storage at 25oC and 4oC, respectively. Further study revealed that the freeze-dried fermented soymilk rehydrated at 45oC was optimum for the recovery of L. casei with improvement in recovery for 0.68 log when sorbitol was added. A higher percent of survival was noted when the dried soymilk was stored at 4oC than at 25oC with improved viability at the end of 5 weeks storage for approximately 6 log for drinks with and without sorbitol. Fermented dried soymilk with sorbitol afforded significant tolerance of L. casei to acid stress. Generally, a stable probiotic diary product was prepared in which the concentration of L. casei remained above therapeutic level of 107 cfu/ml.

Effects of Persian gum and gum Arabic on the survival of Lactobacillus plantarum PTCC 1896, Escherichia coli, Xanthomonas axonopodis, and Saccharomyces cerevisiae during freeze drying

2017 ◽  
Vol 119 (2) ◽  
pp. 331-341 ◽  
Author(s):  
Elyas Mohammadi-Gouraji ◽  
Mahmoud Sheikh-Zeinoddin ◽  
Sabihe Soleimanian-Zad
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Lactobacillus Plantarum ◽  
Cold Storage ◽  
Freeze Drying ◽  
Skim Milk ◽  
Gum Arabic ◽  
Protective Agent ◽  
Content Type ◽  
Xanthomonas Axonopodis

Purpose The purpose of this paper is to evaluate the protective effects of Persian gum and gum Arabic on the survival of Lactobacillus plantarum subsp. plantarum PTCC 1896, Escherichia coli, Xanthomonas axonopodis, and Saccharomyces cerevisiae during freeze drying. Design/methodology/approach Cultures were harvested from the early stationary phase and enumerated after dilution according to the Milse Misra method. Bacterial suspensions were mixed with protective agents and frozen at –80°C before drying in a freeze dryer. Survival rates were determined both immediately during freeze drying and after 14 days of cold storage (at 4°C). Findings Compared to gum Arabic 5 and 10 percent (W/V) or skim milk 10 percent (W/V), Persian gum 1 percent (W/V) showed no significantly different effects on the survival of Lactobacillus plantarum subsp. plantarum PTCC 1896 (p<0.05). Similarly, no significant differences (p<0.05) were observed between Persian gum 6 percent (W/V), gum Arabic 6 percent (W/V), the combination of Persian gum 3 percent (W/V) and gum Arabic 3 percent (W/V), and skim milk 10 percent (W/V) in terms of their effects on the survival of Escherichia coli. Skim milk 10 percent (W/V) was, however, found to have significant (p<0.05) effects on the survival of Xanthomonas axonopodis and Saccharomyces cerevisiae. Statistically significant (p<0.05) effects were observed after 14 days of cold storage (4°C) by Persian gum 6 percent (W/V) on the survival of Escherichia coli and by gum Arabic 6 percent (W/V) on the survival of Xanthomonas axonopodis and Saccharomyces cerevisiae. It was concluded that protective agents could be replaced by Persian gum for its effect on the survival rate of Escherichia coli and by skim milk for its effects on the survival of Xanthomonas axonopodis and Saccharomyces cerevisiae. Persian gum 6 percent (W/V) seemed to be the best protective agent for Escherichia coli during 14 days of its storage as gum Arabic 6 percent (W/V) seemed to have the same performance for Xanthomonas axonopodis and Saccharomyces cerevisiae. Persian gum 1 percent (W/V) was also found an alternative protective agent for the freeze drying of Lactobacillus plantarum subsp. plantarum PTCC 1896. Originality/value As Iranian Persian gum is cheap due to its wide availability and seems to have effects similar to those of gum Arabic and skim milk at low concentrations, it may be considered a good candidate for industrial applications.

scholarly journals Survival rate of Saccharomyces boulardii adapted to a functional freeze-dried yoghurt, related to processing, storage and digestion by experimental Wistar rats

2017 ◽  
Vol 7 (2) ◽  
pp. 98 ◽  
Author(s):  
Hector Eduardo Martinez-Flores ◽  
Eunice Tranquilino-Rodriguez ◽  
Jose O. Rodiles-Lopez ◽  
Rafael Zamora-Vega ◽  
Rafael Salgado-Garciglia ◽  
...  
Keyword(s):  
Survival Rate ◽  
Wistar Rats ◽  
Freeze Drying ◽  
Skim Milk ◽  
Gastrointestinal Transit ◽  
Saccharomyces Boulardii ◽  
Beneficial Effects ◽  
Freeze Dried ◽  
Free Cells

Background: Saccharomyces boulardii is a probiotic clinically effective in the prevention and treatment of antibiotic induced diarrhea in both children and adults, Clostridium difficile infections, inflammatory bowel disease, and other gastrointestinal disorders. However, the microorganisms need to survive the gastrointestinal transit and arrive to their action site alive in order to exert their beneficial effects. Microencapsulation is an alternative to improve the viability of probiotic in foods which can also survive in the gastrointestinal conditions. Freeze--drying is a method of dehydration that does not affect nutrients and bioactive compounds, such as probiotics contained in foods. All of them will increase the survival rate of S. boulardii.Purpose of this study: This study focused on formulae freeze-dried yogurt containing inulin, vegetable palm oil, and S. boulardii, both as free cells and in microencapsulated form. Also, theeffect of ampicillin associated S. boulardii.Methods: Yogurts were given to an “in vivo” digestion process, using male Wistar rats. The survival of S. boulardii was subsequently evaluated in colon and feces. For this study, six treatments of four of rats were used: i) control rats ii) rats fed with yogurt containing S. boulardii as free cells, iii) rats fed with yogurt containing S. boulardii in micro-encapsulated form, iv) control rats fed with penicillin, v) rats fed with ampicillin plus yogurt containing S. boulardii as free cells, and vi) rats fed with penicillin plus yogurt containing S. boulardii in micro-encapsulated form.Results: The study demonstrated it was feasible to freeze-dry the S. boulardii and incorporate it into a yogurt made with skim milk, inulin, and unsaturated vegetable oil. The freeze-drying process not affected the survival of the S. boulardii (p<0.05). Microencapsulation increased the survival of S. boulardii on 1.77-Log CFU/g, and the presence of S. boulardii was only detected in colon and feces of those rats which ingested ampicillin, regardless to the formula contained the probiotic.Conclusion: This study demonstrated that freeze-drying maintains the survival of S. boulardii in the evaluated foods and that micro-encapsulation increases the survival of this probiotic. Furthermore, S. boulardii was installed in the gastrointestinal tract when the microbial flora was  damaged by ampicillin.Keywords: Yogurt, probiotic, Saccharomyces boulardii, micro-encapsulation, freeze-drying.

scholarly journals Preservation of Indigenous Fungal Cultures by Freeze Drying Technique using Skim Milk and Honey as the Protectants

2021 ◽  
pp. 36-42
Author(s):  
G. B. Olukotun ◽  
B. B. Adamu ◽  
O. J. Asake ◽  
S. S. Leh-Togi Zobeashia
Keyword(s):  
Freeze Drying ◽  
Academic Research ◽  
Skim Milk ◽  
Cassava Starch ◽  
Living Condition ◽  
Control Measures ◽  
Sub Saharan Africa ◽  
Residual Water ◽  
Microbial Cultures ◽  
Freeze Dried

COVID-19 pandemic movement restrictions as part of the control measures put in place by countries in Sub-Saharan Africa (SSA) has implications on many sectors which include very high costs of importing materials owing to high exchange rates as well as non- availability of microbial cultures for food/ industrial productions, medical/academic research and applications because of fear of new microbial infections and bio-terrorism. Overcoming these challenges in SSA requires developing better policies and packages to confront the challenges by way of rebooting their strategies and policies for sustainable economic growth through reawakening the potentials they have. The maintenance and production of reliable pure microbial cultures with desirable quality is a key operation and is the first significant stage in the success of fungal applications in any scientific venture where they are used. For many years the process of freeze-drying (lyophilisation) has been employed primarily with the purpose of preserving living materials, including microorganisms, for extended periods of time; this is possible because, upon dehydration, substances no longer change as a consequence of the usual turnover of metabolic reactions characteristic of the living condition. This study assessed lyophilization (freeze drying) of some indigenous filamentous fungal cultures (Spores) using skim milk and honey (supports being maize and cassava flours) as the protectants and then critically compared the two protective media for the preservation of active filamentous fungi spores for the first time, and from the data obtained, their applications were optimised. Some fungal isolates(Aspergillus sp., Mucor sp., Penicillum sp., Fusarium sp., Rhizopus sp., Cladosporium sp. Alternaria sp. and Geotricum sp.) previously purified and identified were obtained from the Products Development Unit, National Biotechnology Development Agency, Abuja, Nigeria and were re-validated where their viability and purity were confirmed. The samples were Freeze Dried in the respective medium and monitored immediately after. After the freeze‐drying, the residual water contents were between 0.20-0.32%, 0.39-0.49% and 0.33-0.41%, respectively, with skim milk, Honey with Cassava Starch and honey with Maize Starch. The driedspore viabilities were between 96% (Aspergillus spores in Reconstituted Skim Milk) and 21% (Geotricum spores in Honey with Cassava Starch. Among the protective agents used, skim milk was found to be the best protectant.Each fungal isolate was considered viable if the rate of growth present was the same as that of the original culture and if the morphology of the colony matched the fungal identification documented for each species. All lyophilized fungal species were found viable from both type of lyophilized materials, skim milk and honey and showed the initial colony characteristics and growth rates.

Viability, Efficacy, and Storage Stability of Freeze-Dried Biocontrol Agent Candida sake Using Different Protective and Rehydration Media

2001 ◽  
Vol 64 (6) ◽  
pp. 856-861 ◽  
Author(s):  
M. ABADIAS ◽  
N. TEIXIDÓ ◽  
J. USALL ◽  
A. BENABARRE ◽  
I. VIÑAS
Keyword(s):  
Freeze Drying ◽  
Storage Stability ◽  
Storage Temperature ◽  
Penicillium Expansum ◽  
Freeze Dried ◽  
Skimmed Milk ◽  
The Stability ◽  
Candida Sake ◽  
Initial Starting ◽  
And Storage

Viability, efficacy against Penicillium expansum on Golden Delicious apples, and storage stability of freeze-dried Candida sake strain CPA-1 were studied. The effect of several protective agents and rehydration media was investigated in the freeze drying of C. sake. Skimmed milk at 10% concentration was a good rehydration medium for all protectants tested. In general, good viability results were obtained when the same solution was used as a protectant and as a rehydration medium. The best survival was obtained when C. sake cells were protected with 10% lactose + 10% skimmed milk and rehydrated with skimmed milk (85% viability). The potential for biocontrol of the best freeze-dried treatments against P. expansum on apples was compared with that of fresh cells. Freeze-dried treatments at 1 × 107 CFU/ml reduced the incidence of decay by 45 to 66%. The best biocontrol effect was obtained with cells that had been freeze dried using 10% lactose + 10% skimmed milk as a protectant and 1% peptone as a rehydration medium, with a 66% reduction in rot incidence. However, in all treatments, the efficacy of freeze-dried cells was significantly lower than fresh cells. The stability of freeze-dried samples decreased during storage and was influenced by storage temperature. In the best treatment, storage of C. sake cells for 60 days at 4°C resulted in final concentrations of 2.5 × 108 CFU/ml, which was a 10-fold reduction in relation to the initial starting concentration of cells prior to freeze drying.

scholarly journals Combinatorial Effects of Protective Agents on Survival Rate of the Yeast Starter, Saccharomyces cerevisiae 88-4, after Freeze-Drying

2021 ◽  
Vol 9 (3) ◽  
pp. 613
Author(s):  
Young-Wook Chin ◽  
Saerom Lee ◽  
Hwan Hee Yu ◽  
Seung Jae Yang ◽  
Tae-Wan Kim
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Response Surface Methodology ◽  
Survival Rate ◽  
Response Surface ◽  
Freeze Drying ◽  
Skim Milk ◽  
Fermented Foods ◽  
Brewing Yeast ◽  
Protective Agents ◽  
Freeze Dried

A yeast starter is formulated for commercial practices, including storage and distribution. The cell viability of the yeast starter is one of the most important factors for manufacturing alcoholic beverages to ensure their properties during the fermentation and formulation processes. In this study, 64 potential protective agents were evaluated to enhance the survival rate of the brewing yeast Saccharomyces cerevisiae 88-4 after freeze-drying. In addition, the optimized combination of protective agents was assessed for long-term storage. Finally, response surface methodology was applied to investigate the optimal concentration of each protectant. Twenty of the 64 additives led to an increase in the survival rate of freeze-dried S. cerevisiae 88-4. Among the various combinations of protectants, four had a survival rate >95%. The combination of skim milk, maltose, and maltitol exhibited the best survival rate of 61% after 42 weeks in refrigerated storage, and the composition of protectants optimized by response surface methodology was 6.5–10% skim milk, 1.8–4.5% maltose, and 16.5–18.2% maltitol. These results demonstrated that the combination of multiple protectants could alleviate damage to yeasts during freeze-drying and could be applied to the manufacturing starters for fermented foods.

scholarly journals Feeding Lactobacilli as probiotic and proportion of Escherichia coli in the intestine of calves

1970 ◽  
Vol 26 (1) ◽  
pp. 17-22
Author(s):  
SM Amanullah ◽  
MS Alam ◽  
RN Subarna ◽  
R Bateen ◽  
KS Huque ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Mass Production ◽  
Freeze Drying ◽  
Intestinal Wall ◽  
Bacterial Cells ◽  
E Coli ◽  
Freeze Dried ◽  
Colony Forming Units ◽  
Agar Media ◽  
De Man

A study was conducted to determine the ability of oral Lactobacillus bacteria as probiotic to increase the Lactobacilli and decrease the Escherichia coli (E. coli) population in the intestine of calves. Bacteria were isolated from yoghurt (Dahi) with selective de Man, Rogosa and Sharpe (MRS) agar media and identified as Lactobacillus, followed by mass production of bacterial cells and freeze drying. Four one-day-old calves were divided into two groups. One group (n=2) was fed freeze-dried bacterial cells and remaining group (n=2) was a control. After 60 days, one calf from each group was slaughtered to enumerate Lactobacillus and E. coli bacteria on intestinal wall. The number of colony-forming units (cfu) of Lactobacillus was significantly (p>0.01) higher in the intestinal wall of Lactobacillus-fed calf than in the control. On the other hand the number of E. coli was significantly (p>0.01) lower in Lactobacillus-fed calf. DOI: 10.3329/bvet.v26i1.4627 Bangl. vet. 2009. Vol. 26, No. 1, 17-22

scholarly journals The effect of freeze-drying media and storage temperature on ultrastructure and DNA of freeze-dried buffalo bull spermatozoa

2016 ◽  
Vol 5 (6) ◽  
pp. 524-535 ◽  
Author(s):  
Mohamed I. Shahba ◽  
Reda I. El-Sheshtawy ◽  
Abdel-Salam I. El-Azab ◽  
Alaa E. Abdel-Ghaffar ◽  
Maha S. Ziada ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Storage Temperature ◽  
Freeze Dried ◽  
And Storage

scholarly journals Penyimpanan Bakteri Escherichia coli Dan Streptococcus pneumonie Pada Media Cryoprotective Dengan Metode Freeze Drying

2020 ◽  
Vol 12 (1) ◽  
pp. 24
Author(s):  
Yati Supriatin Supriatin ◽  
Fitri Fadhilah Fadhilah ◽  
Vanessa Ayu Sumirat
Keyword(s):  
Escherichia Coli ◽  
Cell Viability ◽  
Freeze Drying ◽  
Skim Milk

Proses perbanyakan dan penyimpanan bakteri menjadi hal yang harus diperhatikan karena cara penyimpanan sangat terkait dengan perubahan sifat bakteri yang disimpan. Di Laboratorium, kultur bakteri murni dipindahkan dengan metode subkultur. Kekurangan subkultur� berulang adalah memakan waktu, beresiko kontaminasi dan mutasi genetik. Penelitian ini bertujuan untuk mengembangkan penyimpanan bakteri jangka panjang yang aplikatif di Laboratorium Mikrobiologi serta menentukan jenis Cryoprotectan Agent yang dapat mempertahankan viabilitas sel Escherichia coli dan Streptococcus pneumonie dengan metode Freeze Drying. Metode penelitian yang digunakan adalah eksperimen dengan menambahkan Skim Milk 10% dan gliserol 10% sebagai Cryoprotectan Agent pada pelet sel Escherichia coli dan Streptococcus pneumonie dengan metode Freeze Drying. Digunakan kontrol tanpa penambahan Cryoprotectan Agent dengan metode Freeze Drying dan kontrol tanpa penambahan Cryoprotectan Agent� yang disimpan dalam refrigator (non Freeze Drying) kemudian jumlah koloni bakteri dihitung setelah masa simpan 2,4,6 minggu.Selanjutnya data yang diperoleh diolah secara statistik menggunakan metode statistik non parametrik kruskal wallis . Hasil penelitian menunjukkan bahwa Skim Milk 10% mampu mempertahankan viabilitas Sel Escherichia coli dengan persentase penurunan viabilitas paling rendah yaitu 4,2%, namun� jenis Cryoprotectan agent metode Freeze Dry belum mampu mengawetkan dan mempertahankan viabilitas sel Streptococcus pneumonie.Kata Kunci: Cryoprotectan Agent; Cell viability; Escherichia coli;, Streptococcus pneumonie; Freeze ��Drying

Sign in / Sign up

Export Citation Format

Share Document