Influence of Reconstitution on Isolation and Enumeration of Listeria monocytogenes from Milk Powder Used for Reference Samples

1991 ◽  
Vol 54 (2) ◽  
pp. 124-126 ◽  
Author(s):  
PAUL H. IN'T VELD ◽  
POP S. S. SOENTORO ◽  
ELLEN H. M. DELFGOU-VAN ASCH ◽  
SERVE NOTERMANS
Keyword(s):  
Heat Stress ◽  
Listeria Monocytogenes ◽  
Osmotic Stress ◽  
Spray Drying ◽  
Osmotic Shock ◽  
Milk Powder ◽  
Drying Process ◽  
Isolation Methods ◽  
Reference Samples ◽  
Spray Dried

To test the performance of the Listeria isolation methods, reference samples consisting of gelatin capsules filled with spray-dried milk powder containing Listeria have been developed. During the spray-drying process the Listeria cells are exposed to heat stress and are susceptible to osmotic stress during the reconstitution procedure. To limit the effect of osmotic shock, the milk powder has to be encapsulated in gelatin in order to guarantee slow dissolution. Furthermore, the capsules have to be preen-riched in a nonselective medium. The practical consequences of these findings are discussed.

scholarly journals Staphylococcal Food Poisoning Associated with Spray-Dried Milk

1955 ◽  
Vol 53 (4) ◽  
pp. 387-397 ◽  
Author(s):  
P. H. R. Anderson ◽  
Doris M. Stone
Keyword(s):  
Spray Drying ◽  
Clinical Features ◽  
Milk Powder ◽  
Food Poisoning ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Large Numbers ◽  
Heat Treated ◽  
Drying Chamber ◽  
Spray Dried

SummaryEight explosive outbreaks of food poisoning, occurring in school canteens in England during 1953 and affecting 1190 known cases, are described. The clinical features were characteristic of the toxin type of illness. No deaths occurred.The food causing all of these outbreaks was prepared from spray-dried skim milk powder. It was not subsequently heat-treated and was usually consumed 3–4 hr. after preparation.The spray-dried milk powder proved to contain a high content of bacteria, including large numbers of Staph. aureus, of a phage pattern often associated with food poisoning. The assumption was therefore made that these outbreaks were caused by staphylococcal enterotoxin.Because the food was often consumed within 3–4 hr. of reconstitution of the milk powder—before, in fact, the staphylococci had had time to grow—it is concluded that the poisoning must have been due mainly to pre-formed toxin.Consideration is given to the opportunities for the formation of toxin in a spray-drying plant, and reasons are brought forward for believing that it is formed mainly in the balance tank where the warm milk is kept, sometimes for several hours, before passing into the final drying chamber.The processing of the milk and the precautions for preventing contamination of the finished product are discussed.

scholarly journals Freeze versus Spray Drying for Dry Wild Thyme (Thymus serpyllum L.) Extract Formulations: The Impact of Gelatin as a Coating Material

2021 ◽  
Author(s):  
Aleksandra A. Jovanović ◽  
Steva M. Lević ◽  
Vladimir B. Pavlovic ◽  
Smilja B. Markovic ◽  
Rada V. Pjanovic ◽  
...  
Keyword(s):  
Spray Drying ◽  
Dry Weight ◽  
Drying Process ◽  
Scanning Calorimetry ◽  
Coating Agent ◽  
Microwave Assisted ◽  
Freeze Dried ◽  
Wild Thyme ◽  
The Impact ◽  
Spray Dried

Freeze drying was compared with spray drying regarding feasibility to process wild thyme drug in order to obtain dry formulations at laboratory scale starting from liquid extracts produced by different extraction methods: maceration, heat-, ultrasound-, and microwave-assisted extractions. Higher powder yield (based on the dry weight prior to extraction) was achieved by freeze than spray drying and lower loss of total polyphenol content (TPC) and total flavonoid content (TFC) due to the drying process. Gelatin as a coating agent (5% w/w) provided better TPC recovery by 70% in case of lyophilization and higher powder yield in case of spray drying by diminishing material deposition on the wall of the drying chamber. The resulting gelatin-free and gelatin-containing powders carried polyphenols in amount ~190 and 53-75 mg gallic acid equivalents GAE/g of powder, respectively. Microwave-assisted extract formulation distinguished from others by higher content of polyphenols, proteins and sugars, higher bulk density and lower solubility. The type of the drying process affected mainly position of the gelatin-derived -OH and amide bands in FTIR spectra. Spray dried formulations compared to freeze dried expressed higher thermal stability as confirmed by differential scanning calorimetry analysis and higher diffusion coefficient; the last feature can be associated with the lower specific surface area of irregularly shaped freeze-dried particles (151-223 µm) compared to small microspheres (~8 µm) in spray-dried powder.

scholarly journals New recovery system for milk powder in spray drying process.

1991 ◽  
Vol 17 (1) ◽  
pp. 216-220
Author(s):  
Shun-ichi Kudoh ◽  
Jiro Koga ◽  
Shiro Matsumoto ◽  
Ichiro Inoue
Keyword(s):  
Spray Drying ◽  
Milk Powder ◽  
Drying Process ◽  
Recovery System

scholarly journals Survival of thermophilic spore-forming bacteria in a 90+ year old milk powder from Ernest Shackelton's Cape Royds Hut in Antarctica

2006 ◽  
Vol 73 (2) ◽  
pp. 235-243 ◽  
Author(s):  
Ron S Ronimus ◽  
Andreas Rueckert ◽  
Hugh W Morgan
Keyword(s):  
Milk Powder ◽  
Soil Samples ◽  
Drying Process ◽  
Thermophilic Bacilli ◽  
The World ◽  
Antarctic Expedition ◽  
Anoxybacillus Flavithermus ◽  
Low Levels ◽  
Spore Forming Bacteria ◽  
Spray Dried

Milk powder taken to Antarctica on Shackelton's British Antarctic Expedition in 1907 was produced in New Zealand by a roller drying process in the first factory in the world dedicated to this process. Thermophilic bacilli are the dominant contaminants of modern spray-dried milk powders and the 1907 milk powder allows a comparison to be made of contaminating strains in roller-dried and spray-dried powders. Samples of milk powder obtained from Shackelton's Hut at Cape Royds had low levels of thermophilic contamination (<500 cfu ml−1) but the two dominant strains (Bacillus licheniformis strain F and Bacillus subtilis) were typical of those found in spray-dried powders. Soil samples from the floor of the hut also contained these strains, whereas soils distant from the hut did not. Differences in the RAPD profiles of isolates from the milk powder and the soils suggest that contamination of the milk from the soil was unlikely. It is significant that the most commonly encountered contaminant strain in modern spray-dried milk (Anoxybacillus flavithermus strain C) was not detected in the 1907 sample.

scholarly journals Role of ctc from Listeria monocytogenes in Osmotolerance

2003 ◽  
Vol 69 (1) ◽  
pp. 154-161 ◽  
Author(s):  
Rozenn Gardan ◽  
Ophélie Duché ◽  
Sabine Leroy-Sétrin ◽  
Jean Labadie
Keyword(s):  
Salt Stress ◽  
Heat Stress ◽  
Listeria Monocytogenes ◽  
Osmotic Stress ◽  
Minimal Medium ◽  
Stress Protein ◽  
Transcriptional Level ◽  
Osmotic Stress Tolerance ◽  
Electron Microscopy Analysis

ABSTRACT Listeria monocytogenes is a food-borne pathogen with the ability to grow under conditions of high osmolarity. In a previous study, we reported the identification of 12 proteins showing high induction after salt stress. One of these proteins is highly similar to the general stress protein Ctc of Bacillus subtilis. In this study, induction of Ctc after salt stress was confirmed at the transcriptional level by using RNA slot blot experiments. To explore the role of the ctc gene product in resistance to stresses, we constructed a ctc insertional mutant. No difference in growth was observed between the wild-type strain LO28 and the ctc mutant either in rich medium after osmotic or heat stress or in minimal medium after heat stress. However, in minimal medium after osmotic stress, the growth rate of the mutant was increased by a factor of 2. Moreover, electron microscopy analysis showed impaired morphology of the mutant grown under osmotic stress conditions in minimal medium. Addition of the osmoprotectant glycine betaine to the medium completely abolished the osmotic sensitivity phenotype of the ctc mutant. Altogether, these results suggest that the Ctc protein of L. monocytogenes is involved in osmotic stress tolerance in the absence of any osmoprotectant in the medium.

scholarly journals Ultrasonic atomizing-assisted spray drying: Effect on the quality of skimmed milk powders

2018 ◽  
Author(s):  
Yuchuan Wang ◽  
Ying Cui ◽  
Bo Wang ◽  
Min Zhang
Keyword(s):  
Particle Size ◽  
Spray Drying ◽  
Milk Powder ◽  
High Quality ◽  
Ultrasonic Atomization ◽  
Atomization Spray ◽  
L Value ◽  
Skimmed Milk ◽  
Spray Dried

Skimmed milk powders (SMP) were produced by ultrasonic atomizing-assisted spray drying (UASD). It was found that UASD can produce high quality SMP (with &lt; 5% moisture content and &lt; 2% insolubility) at lower inlet temperatures (~130℃). The particle size of the UASD-SMP was 10 times smaller (decreased from ~20 µm to 4 µm) than the tranditionally spray-dried SMP and the color appeal of UASD-SMP was also better (L* value increased by &gt; 6 %). Overall, this research shown that UASD can be used to produce small particle size and high quality SMP. Keywords: Skimmed milk powder; ultrasonic atomization; spray dryer; particle size distribution; color  

On The Fabrication and Properties of a Ceramic Cladded Aluminium Powder Using the Spray Drying Process

1998 ◽  
Author(s):  
B. Comas ◽  
C. Mateus ◽  
B. Hansz ◽  
C. Coddet
Keyword(s):  
Spray Drying ◽  
Composite Coatings ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Drying Process ◽  
Manufacturing Method ◽  
Aluminium Powder ◽  
New Family ◽  
Spray Dried ◽  
Scanning Electron

Abstract A new family of spherical powders produced by the spray drying route has been developed. This paper describes as an example the manufacturing method of an Y203-coated aluminum powder. Atmospheric Plasma Spraying (APS) was used to test the corresponding coatings. Morphology and phases of powders and coatings were investigated by optical and scanning electron microscopy while the level of porosity was evaluated using image analysis. Results show that homogenous composite coatings can be obtained from cladded spray dried powders.

327. Spray-dried milk powder. Commercial observations over two years of the effect of high temperature pre-heating

1945 ◽  
Vol 14 (1-2) ◽  
pp. 160-164 ◽  
Author(s):  
E. L. Crossley
Keyword(s):  
High Temperature ◽  
Spray Drying ◽  
Experimental Work ◽  
Milk Powder ◽  
Experimental Period ◽  
Once Daily ◽  
Beneficial Effects ◽  
Commercial Operation ◽  
Experimental Runs ◽  
Spray Dried

The beneficial effects of high-temperature pre-heating of the milk before spray drying constitute the main features which emerged from previous experimental work (1). The bacteriological advantages became obvious during the experimental period, and high-temperature pre-heating at 190°F. was introduced as standard practice following the experimental runs. Further observations have been made during two complete drying seasons, in ordinary commercial operation wherein the milk was collected once daily without special selection and pre-heated to 190°F. without preliminary clarification. This work has afforded opportunity to discover any possible practical difficulties, and also to examine a much wider range of samples than was possible during the experimental period.

Characterization of Hazelnut Milk Powders: A Comparison of Spray-Drying and Freeze-Drying

2018 ◽  
Vol 14 (11-12) ◽  
Author(s):  
Ertan Ermis ◽  
Kübra Özkan Güner ◽  
Mustafa Tahsin Yilmaz
Keyword(s):  
Spray Drying ◽  
Freeze Drying ◽  
Milk Powder ◽  
Angle Of Repose ◽  
Drying Process ◽  
Residual Moisture ◽  
Hausner Ratio ◽  
Powder Samples ◽  
Supporting Material

Abstract Production of hazelnut milk powder (HMP) was investigated using maltodextrin (MD) as supporting material. Spray-drying and freeze-drying techniques were used to obtain the powder material. MD was added at concentrations of 5%, 10% and 15% (w/w) prior to drying. The powder properties were evaluated by determining flowing properties (Hausner ratio and angle of repose), thermal behaviour using DSC, molecular properties using FTIR, solubility and zeta potential. Hausner Ratio for both spray dried (SDHMP) and freze-dried (FDHMP) samples varied from 1.30 to 1.64 corresponding to very poor flow. The FDHM powder samples exhibited slightly lower Hausner Ratio values than SDHM powders. FTIR spectras showed that both SDHM and FDHM exhibited similar absorbance characteristics with slight differences. Lower endothermic transition temperatures were recorded from FDHMP when compared to SDHMP. The solubility in water for both powder samples ranged from 20 to 65 % depending on the drying method and MD content. Based on the residual moisture content, water activity, solubility and flowability, spray drying process was found to produce better quality powders compared to freeze drying process.

Survival of Listeria monocytogenes During the Manufacture and Storage of Nonfat Dry Milk

1985 ◽  
Vol 48 (9) ◽  
pp. 740-742 ◽  
Author(s):  
MICHAEL P. DOYLE ◽  
LOUISE M. MESKE ◽  
ELMER H. MARTH
Keyword(s):  
Listeria Monocytogenes ◽  
Spray Drying ◽  
Skim Milk ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Drying Process ◽  
Dry Milk ◽  
Nonfat Dry Milk ◽  
And Storage ◽  
Moisture Resistant

The ability of Listeria monocytogenes to survive in skim milk during spray drying and to persist in nonfat dry milk during storage was examined. Concentrated (30% solids) and unconcentrated skim milks were inoculated with ca. 105 to 106 L. monocytogenes/ml and spray dried (inlet temperature, 165 ± 2°C; outlet temperature 67 ± 2°C) to a moisture content of 3.6 to 6.4%. The nonfat dry milk was packaged in moisture-resistant film and stored at 25°C for up to 16 wk. A reduction of ca. 1 to 1.5 log10 L. monocytogenes/g occurred during the spray drying process, irrespective of whether the milk was concentrated or not before spray drying. The organism progressively died during storage at 25°C, with a &gt;4-log10 CFU/g decrease occurring within 16 wk of storage.

Sign in / Sign up

Export Citation Format

Share Document