Inactivation of Salmonella enterica Serovar Senftenberg 775W in Liquid Whole Egg by Ultrahigh Pressure Homogenization

2008 ◽  
Vol 71 (11) ◽  
pp. 2283-2288 ◽  
Author(s):  
R. M. VELÁZQUEZ-ESTRADA ◽  
M. M. HERNÁNDEZ-HERRERO ◽  
T. LÓPEZ-PEDEMONTE ◽  
B. GUAMIS-LÓPEZ ◽  
A. X. ROIG-SAGUÉS

Two batches of samples of liquid whole egg were inoculated with a load of approximately 3 and 7 log CFU/ml, respectively, of Salmonella enterica serovar Senftenberg 775W and submitted to different ultrahigh pressure homogenization (UHPH) treatments at 150, 200, and 250 MPa. The inlet temperature of the samples was 6°C. Counts of viable and injured Salmonella cells were obtained 2 h after the UHPH treatments and after 5, 10, 15, and 20 days of storage at 4°C. The level of pressure applied influenced the lethality attained significantly (P < 0.05). In the samples with an initial load of approximately 7 log CFU/ml, the highest lethality value of 3.2 log CFU/ml was obtained at 250 MPa, and it is similar to those values reported in other surveys for thermal pasteurization with this same Salmonella strain. When the initial load was approximately 3 log CFU/ml, total inactivation was apparently obtained after the 250-MPa treatment (2.7 log CFU/ml). After 10 days of storage at 4°C, Salmonella counts decreased in UHPH-treated samples, and colonies were not observed in tryptone soy agar and yeast extract medium. Nevertheless, presence of viable Salmonella cells was detected with the VIDAS Salmonella immunoassay method during the entire storage period. These results encourage further investigation of UHPH processing of liquid whole egg, assaying the possibility of using higher pressures and fluid inlet temperatures.

2002 ◽  
Vol 65 (7) ◽  
pp. 1177-1178 ◽  
Author(s):  
N. COOK ◽  
J. ELLISON ◽  
A. S. KURDZIEL ◽  
S. SIMPKINS ◽  
J. P. HAYS

Nucleic acid sequence–based amplification (NASBA) was applied to the detection of Salmonella enterica cells in liquid whole egg. Samples (25 g) of liquid whole egg inoculated with Salmonella cells were enriched for 16 h in buffered peptone water, and the NASBA procedure was effective in detecting the presence of Salmonella in samples inoculated with 10 to 100 CFU prior to enrichment.


2003 ◽  
Vol 20 (5) ◽  
pp. 593-600 ◽  
Author(s):  
Pilar Mañas ◽  
Rafael Pagán ◽  
Ignacio Alvarez ◽  
Santiago Condón Usón

2021 ◽  
pp. 34-37
Author(s):  
Екатерина Владимировна Ульянова ◽  
Дарья Владиславовна Андриевская

Стабильность (розливостойкость) в течение длительного времени - одна из важных составляющих качественных характеристик спиртных напитков виноградного происхождения, в том числе коньяков. Коньяк представляет собой сложную многокомпонентную систему, включающую более 800 различных соединений, в том числе фенольный комплекс древесины дуба и минеральные вещества. В процессе длительного хранения под воздействием ряда факторов эти соединения, вступая во взаимодействие друг с другом, могут образовывать различные виды помутнений, что влечет за собой потерю товарного вида готовой продукции. Целью настоящей работы стало исследование влияния отдельных показателей физико-химического состава обработанных коньяков на изменение их стабильности в процессе хранения. В качестве объектов исследования использовали образцы обработанных розливостойких коньяков отечественного производства, которые были разделены в зависимости от возраста на четыре группы: I группа - 3-летние, 4-летние и 5-летние (23 образца); II группа - выдержанные «КВ» и выдержанные высшего качества «КВВК» (15 образцов); III группа - старые «КС» (9 образцов); IV группа - очень старые «ОС» (7 образцов). Образцы хранили в течение 6 мес. при температуре 22…25 °С, в условиях, не допускающих попадания прямых солнечных лучей. В процессе хранения проводили мониторинг изменения физико-химических показателей, розливостойкости и органолептических характеристик исследуемых образцов с периодичностью 1 раз в месяц. Установлено, что на всем протяжении хранения физико-химические показатели исследованных образцов оставались в пределах нормы. Однако, в отдельных образцах, на определенном этапе эксперимента (после 2 мес. хранения) было отмечено появление осадка. Кроме того, по результатам определения склонности к различным видам помутнений был отмечен рост доли коньяков, нестойких к необратимым коллоидным и кристаллическим помутнениям в трех группах, кроме IV группы. Полученные данные по исследованию структуры осадков и результаты тестов на розливостойкость согласуются с характером изменений массовых концентраций катионов натрия и кальция, а также фенольных соединений. В целом полученные результаты проведенных исследований показали необходимость контроля массовой концентрации катионов натрия и кальция, а также фенольных соединений при прогнозировании розливостойкости коньяков. One of the important components of the quality characteristics of alcoholic beverages of grape origin, including cognacs, is their stability (bottling resistance) for a long time. Cognac is a complex multicomponent system that includes more than 800 different compounds, including the phenolic complex of oak wood and minerals. During long-term storage, under the influence of a number of factors, these compounds, interacting with each other, can form various types of turbidity, which entails the loss of the presentation of the finished product. The aim of this work was to study the effect of individual indicators of the physical and chemical composition of processed cognacs on the change in their stability during storage. As objects of research, we used samples of processed bottling-resistant cognacs of domestic production, which were divided, depending on age, into four groups: Group I - three-year-old, four-year-old and five-year-old (23 samples); Group II - matured «KV» and matured of the highest quality «KVVK» (15 samples); Group III - old «KS» (9 samples); IV group - very old «OS» (7 samples). The samples were stored for 6 months at a temperature of 22…25 °C, in conditions out of direct sunlight. During storage, changes in physical and chemical parameters, bottling resistance and organoleptic characteristics of the samples under study were monitored at a frequency of 1 time per month. It was found that during the entire storage period, the physicochemical indicators of the studied samples remained within the normal range. However, in some samples, at a certain stage of the experiment (after 2 months of storage), the appearance of a precipitate was noted. In addition, according to the results of determining the tendency to various types of cloudiness, an increase in the proportion of cognacs unstable to irreversible colloidal and crystalline cloudiness was noted in three groups, except for group IV. The data obtained on the study of the structure of sediments and the results of tests for pouring resistance are consistent with the nature of changes in the mass concentrations of sodium and calcium cations, as well as phenolic compounds. In general, the results of the studies carried out showed the need to control the mass concentration of sodium and calcium cations, as well as phenolic compounds when predicting the pouring resistance of cognacs.


2001 ◽  
Vol 64 (10) ◽  
pp. 1584-1591 ◽  
Author(s):  
A. GELMAN ◽  
L. GLATMAN ◽  
V. DRABKIN ◽  
S. HARPAZ

Sensory and microbiological characteristics of pond-raised freshwater silver perch (Bidyanus bidyanus) fish, during cold storage over a period of 25 days were evaluated. Whole fish (averaging 400 g each) were stored in cold storage rooms at either 0 to 2°C, 5°C, or 5°C + potassium sorbate as a preservative. The organoleptic and hypoxanthine test results show that the treatment of potassium sorbate can slow the process of spoilage by about 5 days. Yet, the most important factor affecting the shelf life of these fish is the storage temperature. Keeping the fish at 0 to 2°C can prolong the storage prior to spoilage by 10 days compared with those kept at 5°C. These results obtained through organoleptic tests are corroborated by both the chemical (hypoxanthine and total volatile basic nitrogen) and to some extent by the physical (cosmos) tests. The initial total bacteriological counts were 5 × 102 CFU/cm2 for fish surface and <102 CFU/g for fish flesh, and these counts rose continuously, reaching about 106 CFU/g (0 to 2°C) and 107 CFU/g (5°C) in flesh and 107 to 108 CFU/cm2 on the surface by the end of the storage period. The addition of potassium sorbate led to a smaller increase in bacterial numbers, especially during the first 15 days. Bacterial composition fluctuated during storage. The initial load on the fish surface was predominantly mesophilic and gram positive and consisted mostly (80%) of Micrococci, Bacillus, and Corynebacterium. During the next 10 days, these bacteria were practically replaced by gram-negative flora comprised mostly of Pseudomonas fluorescens that rapidly increased with storage time and accounted for 95% after 15 days.


Author(s):  
M. M. Góngora-Nieto ◽  
L. Seignour ◽  
P. Riquet ◽  
P. M. Davidson ◽  
G. V. Barbosa-Cánovas ◽  
...  

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Hidas Karina Ilona ◽  
Ildikó Csilla Nyulas-Zeke ◽  
László Friedrich ◽  
Anna Visy ◽  
Judit Csonka ◽  
...  

Eggs are widely utilized because of their high nutrient value, coagulating, foaming, emulsifying and sometimes even colouring or flavouring facilities in food manufacturing. Production of processed egg products shows an increasing trend. Frozen products belong to first processing, their shelf life can increase up to 1 year. By freezing, a large reduction in microbial loss can be achieved. But different undesirable processes can occur. The effect of freezing on animal cells is highly dependent on freezing parameters. It has a different effect on egg subtituents. Egg yolk undergoes a gelation process while proteins can denaturate. In our study pasteurized liquid egg products (liquid egg white, liquid egg yolk and liquid whole egg) were frozen by dripping into liquid nitrogen. After that, a 14-day frozen storage experiment was carried out at -18°C. Before freezing and on the 1th, 7th and 14th days of storage experiment pH, dry matter content, colour and calorimetric properties (denaturation temperatures and enthalpy of denaturation) with differential scanning calorimetry were tested. For statistical analysis, one-way ANOVA (α = 0.05) was employed. In our experiment, we found no significant change in calorimetric properties of liquid egg white after freezing, but significant decreasing of enthalpy and denaturation temperatures of liquid egg yolk and liquid whole egg was identified. In contrast, frozen storage had a decreasing effect in all these products. Freezing caused a clearly visible colour change in LEW, a visible change in colour of LWE and a very clearly visible change in colour of LEY. In case of LEW and LEY changes increased to clearly visible 14 days. In conclusion, our results show that frozen storage had a greater effect on liquid egg products properties than freezing in liquid nitrogen.


1992 ◽  
Vol 15 (4) ◽  
pp. 133-136 ◽  
Author(s):  
J. Delves-Broughton ◽  
G.C. Williams ◽  
Samantha Wilkinson
Keyword(s):  

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