scholarly journals Behavior of Native Food Isolates of Listeria monocytogenes and Listeria innocua under the Influence of Selected Cultural Attributes and Heat and Cold Treatments

2021 ◽  
Author(s):  
Jayanth Sunderraj Hampapura ◽  
Varadaraj Mandyam Chakravarathy
Keyword(s):  
Storage Temperature ◽  
Cold Treatment ◽  
Skim Milk ◽  
Brain Heart Infusion ◽  
Storage Period ◽  
Growth Responses ◽  
Initial Inoculum ◽  
Appreciable Increase ◽  
Viable Population ◽  
Ph Level

The present investigation assesses the influence of cultural attributes and heat and cold treatments on the behaviour of native toxigenic L. monocytogenes CFR 1302 and non-toxigenic L. innocua CFR 1304 in selected medium. The growth responses of L. monocytogenes and L. innocua under the influencing factors of storage temperature (10-40°C), pH level (5.5-7.5), and storage period (6-48 h) in brain heart infusion and nutrient broths revealed closeness between observed and predicted populations. Response surface plots were generated for the growth behavior of the two test cultures as a function of pH level. The toxigenic L. monocytogenes CFR 1302 could reach a higher viable population. The effect of heat treatment on Listeria spp. in selected five heating menstra showed the lowest D-value of 3.7 min at 60°C for L. innocua CFR 1304 in Milli-Q water to the highest of 8.4 min at 56°C for L. monocytogenes CFR 1302 in skim milk. The average z-value across the heating menstra for L. monocytogenes was 27.3°C as against that of 22°C for L. innocua. In the case of cold treatment, storage of 4 and 8°C resulted in appreciable increase in counts of L. monocytogenes CFR 1302 from the initial inoculum introduced in selected media. At -20°C, there was a slight decrease in the viable population. The research data helps to predict the viable populations of L. monocytogenes as a part of risk assessment in the food chain. This is of significance in providing safe and healthy food to human population.

scholarly journals Changes in Particle Size, Sedimentation, and Protein Microstructure of Ultra-High-Temperature Skim Milk Considering Plasmin Concentration and Storage Temperature

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2339
Author(s):  
So-Yul Yun ◽  
Jee-Young Imm
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Storage Temperature ◽  
Whey Proteins ◽  
Skim Milk ◽  
Storage Period ◽  
Sediment Analysis ◽  
Sediment Formation ◽  
And Storage ◽  
Ultra High Temperature

Age gelation is a major quality defect in ultra-high-temperature (UHT) pasteurized milk during extended storage. Changes in plasmin (PL)-induced sedimentation were investigated during storage (23 °C and 37 °C, four weeks) of UHT skim milk treated with PL (2.5, 10, and 15 U/L). The increase in particle size and broadening of the particle size distribution of samples during storage were dependent on the PL concentration, storage period, and storage temperature. Sediment analysis indicated that elevated storage temperature accelerated protein sedimentation. The initial PL concentration was positively correlated with the amount of protein sediment in samples stored at 23 °C for four weeks (r = 0.615; p < 0.01), whereas this correlation was negative in samples stored at 37 °C for the same time (r = −0.358; p < 0.01) due to extensive proteolysis. SDS-PAGE revealed that whey proteins remained soluble over storage at 23 °C for four weeks, but they mostly disappeared from the soluble phase of PL-added samples after two weeks’ storage at 37 °C. Transmission electron micrographs of PL-containing UHT skim milk during storage at different temperatures supported the trend of sediment analysis well. Based on the Fourier transform infrared spectra of UHT skim milk stored at 23 °C for three weeks, PL-induced particle size enlargement was due to protein aggregation and the formation of intermolecular β-sheet structures, which contributed to casein destabilization, leading to sediment formation.

scholarly journals Quality properties of non-fat yogurt with addition of whey protein concentrate

2007 ◽  
Vol 23 (5-6-1) ◽  
pp. 291-299 ◽  
Author(s):  
M. Sady ◽  
J. Domagała ◽  
T. Grega ◽  
D. Najgebauer-Lejko
Keyword(s):  
Whey Protein ◽  
Milk Powder ◽  
Skim Milk ◽  
Storage Period ◽  
Skim Milk Powder ◽  
Whey Protein Concentrate ◽  
Protein Concentrate ◽  
Quality Properties ◽  
Sensory Score ◽  
Ph Level

The aim of the study was investigation of quality of fat-free, settype yoghurt made at 5% (w/w) protein level with addition of skim milk powder (SMP) and whey protein concentrate (WPC) blends. The ratio SMP/WPC in used blends was: 1/0; 2/1; 1/2; 0/1. On 1st, 7th and 21st day of refrigerated storage yoghurt was analysed for sensory properties, titrable acidity, pH, free fatty acids (FFA), acetaldehyde, and diacethyl. Also enumeration of viable L. delbrueckii ssp. bulgaricus and S. thermophilus was carried out. During the whole storage period products with SMP/WPC ratio at 1/2 and 2/1 obtained the best sensory score. Addition of WPC to yoghurt significantly decreased lactic acid concentration which positively influenced its stability during shelf life. It was shown that during storage acidity of yoghurt was growing up in concern of pH level. The acetaldehyde content tended to increase significantly in the yoghurt fortified with higher proportion of WPC opposite to diacethyl level which was the lowest in yoghurt with an SMP/WPC addition at 0/1. During storage concentration of both volatile compounds were the highest on 7th day and the lowest on 21st day. The maximum concentration of FFA was stated in products with SMP/WPC ratio 1/2. During the storage period FFA content significantly increased after 7th days and had no changed during next 14 days. The total number of yoghurt bacteria during the whole storage time was up to 1010 and did not vary depending on SMP/WPC ratio. Amount of L. delbrueckii ssp. bulgaricus was about one log cycle lower than S. thermophilus in all kinds of yoghurt.

DRIED MILK POWDER: VII. THE EFFECT OF SEASON OF PRODUCTION ON KEEPING QUALITY

1947 ◽  
Vol 25f (1) ◽  
pp. 13-17
Author(s):  
Jesse A. Pearce ◽  
W. A. Bryce
Keyword(s):  
Storage Temperature ◽  
Milk Powder ◽  
Skim Milk ◽  
Storage Period ◽  
Quality Changes ◽  
Whole Milk ◽  
Keeping Quality

Milk powders of 1% butterfat content, produced in the fall of the year, had higher initial palatability scores than similar powders prepared in the spring.. The skim milk powders from fall milk decreased in quality throughout a storage period of 16 wk. at temperatures of 80°, 100°, or 120° F. Similar powders from spring milk stored at 80° F. increased in quality throughout the storage period while those stored at 100° and 120° F. first increased and then decreased in quality. Powders of 26 or 28% butterfat, produced in the spring or in the fall, had equal initial palatability scores and when stored deteriorated equally. Fail milk powder containing 30% butterfat was better initially than the comparable spring sample, but, when stored, quality changes in both types were about equal. At each storage temperature all whole milk powders deteriorated at about the same rate.

Optimization of Computational Neural Network for Its Application in the Prediction of Microbial Growth in Foods

2001 ◽  
Vol 7 (2) ◽  
pp. 159-163 ◽  
Author(s):  
C. Herv's ◽  
G. Zurera ◽  
R. M. Garcfa ◽  
J. A. Martinez
Keyword(s):  
Microbial Growth ◽  
Storage Temperature ◽  
Chloride Concentration ◽  
Estimation Methods ◽  
Regression Equations ◽  
Growth Responses ◽  
Ph Level ◽  
The One ◽  
And Storage ◽  
Better Than

The power of computational neural networks (CNN) for microbiological growth prediction was evaluated. The training set consisted of growth responses data from a combination of three strains of Salmonella in a laboratory medium as affected by pH level, sodium chloride concentration and storage temperature. The architecture of CNN was designed to contain three input parameters in the input layer and one output parameter in the output layer. For their optimization, algorithms were developed to prune the net connections, obtaining an improvement in the generalization and a decrease in the number of necessary patterns for the training. The standard error of prediction (%SEP) obtained was under 5% using twenty inputs to the net, and the result was significantly smaller than the one obtained using regression equations. Therefore, the usefulness of CNN for modeling microbial growth is appealing, and its improvement promises results that will be better than those obtained by other estimation methods up to now.

Storage of Human Blood Platelets

1974 ◽  
Vol 32 (02/03) ◽  
pp. 405-416 ◽  
Author(s):  
M. R Hardeman ◽  
Carina J L. Heynens
Keyword(s):  
Storage Temperature ◽  
Platelet Rich Plasma ◽  
Blood Platelets ◽  
Storage Period ◽  
Serotonin Uptake ◽  
Hypotonic Shock ◽  
Glycolytic Intermediates

SummaryStorage experiments were performed at 4°, 25° and 37° C with platelet-rich plasma under sterile conditions. In some experiments also the effect of storing platelets at 4° C in whole blood was investigated.Before, during and after three days of storage, the platelets were tested at 37° C for their serotonin uptake and response to hypotonic shock. In addition some glycolytic intermediates were determined.A fair correlation was noticed between the serotonin uptake and hypotonic shock experiments. Both parameters were best maintained at 25° C. Also platelet counting, performed after the storage period, indicated 25° C as the best storage temperature. Determination of glycolytic intermediates did not justify any conclusion regarding the optimal storage temperature. Of the various anticoagulants studied, ACD and heparin gave the best results as to the serotonin uptake and hypotonic shock response, either with fresh or stored platelets. The use of EDTA resulted in the lowest activity, especially after storage.The results of these storage experiments in vitro, correspond well with those in vivo reported in the literature.

scholarly journals Chromatographic Characterization and In Vitro Bioactivity Evaluation of Lactobacillus helveticus Hydrolysates upon Fermentation of Different Substrates

2021 ◽  
Vol 11 (2) ◽  
pp. 811
Author(s):  
Federica Ianni ◽  
Alessandra Anna Altomare ◽  
Beniamino T. Cenci-Goga ◽  
Francesca Blasi ◽  
Luca Grispoldi ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Proteolytic Activity ◽  
Bioactive Peptides ◽  
Biological Activities ◽  
Skim Milk ◽  
Brain Heart Infusion ◽  
Starter Cultures ◽  
Lactobacillus Helveticus ◽  
Food Sources

Among various food sources, milk proteins remain the major vector for functional peptides endowed with several biological activities. Particularly, the proteolytic activity of lactic acid bacteria during milk fermentation has been one of the most followed strategies to produce bioactive peptides. In the present study, the exploration of the activity of several starter cultures, at different fermentation times, was firstly investigated by reversed phase-high performance liquid chromatography. Among the tested strains, Lactobacillus helveticus showed a higher proteolytic activity and it was submitted to further investigations by changing the fermentation substrate (skim milk, brain heart infusion, peptone water) as well as the extraction strategy (trichloroacetic acid vs. glass beads). The chromatographic analyses and the in vitro antioxidant and antihypertensive assays highlighted considerable differences for L. helveticus hydrolysates from different substrates, while a negligible impact by the two extraction protocols emerged. Furthermore, nano-high pressure liquid chromatography coupled with a high resolution mass spectrometry analyzer allowed the preliminary discrimination of fractions from fermented skim milk, likely responsible for the found activity. The obtained results suggest the possibility of varying the fermentation parameters in order to maximize the functional effects of the bioactive peptides.

PRODUCTION OF GRANULATED INSTANT KISSEL BASED ON WHEY AND VEGETABLE RAW MATERIALS

2020 ◽  
Author(s):  
А.Л. Майтаков ◽  
Л.Н. Берязева ◽  
Н.Т. Ветрова ◽  
К.Б. Плотников
Keyword(s):  
Storage Temperature ◽  
Raw Materials ◽  
Storage Period ◽  
Technical Documentation ◽  
Plant Raw Materials ◽  
Temperature Conditions ◽  
Aronia Melanocarpa ◽  
Organoleptic Characteristics ◽  
Local Plant ◽  
The Stability

Разработан новый быстрорастворимый продукт (кисель) с определенным фазовым составом и строением на основе молочной сыворотки и местного растительного сырья – черноплодной рябины (Aronia melanocarpa). Разработана модель технологии производства быстрорастворимого гранулированного продукта (кисель) на основе молочной сыворотки и черноплодной рябины. Исследована сохраняемость киселя в трех температурных режимах: 1-й (21 ± 1)°С; 2-й с низкой плюсовой температурой (5 ± 1)°С; 3-й с повышенной (39 ± 1)°С при влажности окружающей среды 80%. По окончании годичного исследования сохраняемости при температурных режимах (21 ± 1)°С и (5 ± 1)°С изменений в органолептических показателях продукта не наблюдали. Скорость растворения продукта при температурных условиях хранения (21 ± 1)°С и (5 ± 1)°С не изменялась на протяжении 9 мес. Установлено, что при хранении в условиях пониженных положительных температур 4–6°С и в режиме комнатной температуры (21 ± 1)°С исследуемый пищеконцентрат по окончании 6 мес. хранения не изменил свойств по показателям качества. Сроки испытания продукта превышали по длительности в 2 раза заданный срок хранения (коэффициент запаса). Результаты испытаний явились основанием для разработки технической документации на производство быстрорастворимых гранулированных плодово-ягодных киселей. A new fast – soluble product (kissel) with a certain phase composition and structure based on whey and local plant raw materials Aronia melanocarpa. A model of technology for the production of a rapidly soluble granular product (kissel) based on whey and Aronia melanocarpa has been developed. The stability of kissel in three temperature modes was studied: 1st (21 ± 1)°C; 2nd with a low plus temperature (5 ± 1)°C; the 3rd with the increased (39 ± 1)°C at 80% ambient humidity. At the end of a year-long study at temperature conditions (21 ± 1)°С and (5 ± 1)°С, no changes in the organoleptic characteristics of the product were observed. Dissolution rate of the product under storage temperature conditions (21 ± 1)°C and (5 ± 1)°C did not change for 9 months. It is established that when stored at low positive temperatures 4–6°C. With and at room temperature (21 ± 1)°C. At the end of 6 months of storage, the food concentrate under study did not change its properties in terms of quality. The product testing period was 2 times longer than the specified storage period. The test results were the basis for the development of technical documentation for the production of instant granulated fruit and berry kissel.

Effects of Storage Temperature and Preservative Treatment on Shelf Life of the Pond-Raised Freshwater Fish, Silver Perch (Bidyanus bidyanus)

2001 ◽  
Vol 64 (10) ◽  
pp. 1584-1591 ◽  
Author(s):  
A. GELMAN ◽  
L. GLATMAN ◽  
V. DRABKIN ◽  
S. HARPAZ
Keyword(s):  
Shelf Life ◽  
Cold Storage ◽  
Storage Temperature ◽  
Storage Period ◽  
Potassium Sorbate ◽  
Test Results ◽  
Bacterial Composition ◽  
Fish Flesh ◽  
Microbiological Characteristics ◽  
Initial Load

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 &lt;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.

The use of postharvest treatments to extend storage life and to control postharvest wastage of honeydew melons (Cucumis melo L. var. inodorus Naud.) in cool storage

1990 ◽  
Vol 30 (5) ◽  
pp. 693 ◽  
Author(s):  
ME Edwards ◽  
RM Blennerhassett
Keyword(s):  
Water Loss ◽  
Cucumis Melo ◽  
Storage Temperature ◽  
Chilling Injury ◽  
Storage Period ◽  
Storage Conditions ◽  
Storage Life ◽  
Storage Rots ◽  
Wax Coating ◽  
Cucumis Melo L

Three trials were undertaken to study storage conditions and handling procedures required to maximise the postharvest storage life of honeydew melons (Cucumis melo L. var. inodorus Naud.).Honeydew melons treated with chlorine (1000 mg/L), benomyl (250 mg/L) + guazatine (500 mg/L), shrink wrap (17 ym Cryovac XDR film), Semperfresh, wax, or combinations of these treatments were stored at 4 or 8�C, for 4 or 6 weeks. Benomyl plus guazatine reduced the development of storage rots associated with Alternaria and Fusarium spp. The use of shrink wrap and wax reduced water loss by melons but increased fungal infection in some cases. Shrink wrapping combined with the fungicide treatment effectively reduced the incidence of fungal breakdown in the storage period for up to 4 weeks. Wax coating with full strength Citruseal wax caused anaerobic tissue breakdown. Melons were affected by chilling injury at 4�C. Control of bacterial rots with benomyl + guazatine or with chlorine was variable. Semperfresh did not reduce the incidence of fungal breakdown or water loss from the melons. The results indicate that storage of honeydew melons for 4 weeks at 8�C by pretreating with fungicide is possible but the melons soften and rot after 6 weeks, making them unsaleable. Four weeks should be adequate to allow for sea freighting of honeydew melons to markets in South East Asia. Further research is required to determine the optimum storage temperature for honeydew melons.

scholarly journals Pengujian Umur Simpan Kopi Arabika Bubuk Pada Jenis Kemasan dan Suhu Simpan Yang Berbeda

2021 ◽  
Vol 8 (1) ◽  
pp. 37
Author(s):  
Elsera Br Tarigan ◽  
Edi Wardiana ◽  
Handi Supriadi
Keyword(s):  
Shelf Life ◽  
Storage Temperature ◽  
Storage Period ◽  
Fat Content ◽  
Test Method ◽  
Life Test ◽  
Coffee Plantations ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
And Storage

<p><em>Coffee is a beverage that is widely consumed around the world. Proper packaging and storage temperature may extend shelf life of ground coffee. The study aimed to analyze the shelf life of ground Arabica coffee stored in different packaging types and temperature, conducted at smallholder coffee plantations in Garut Regency and the Integrated Laboratory of Indonesian Industrial and Beverage Crops Research Institute, Sukabumi, from June to August 2018. A completely randomized design in factorial was used with 3 factors and 2 replications. The first factor was the packaging type  which consisted of 3 types: thick alumunium  foil 65</em><em>m</em><em> (AF65), thick alumunium  foil 130</em><em>m</em><em> (AF130), and thick lamination 114</em><em>m</em><em> (L144). The second factor was the storage temperature which consisted of 3 levels: 25 <sup>o</sup>C, 35 <sup>o</sup>C, and 45 <sup>o</sup>C, while the third factor was the storage period which consisted of 5 levels: coffee unstored, and coffee stored for 2 weeks, 4 weeks, 6 weeks, and 8 weeks. The variables observed were the water and fat content, and the analysis of shelf life was carried out using the ASLT (Accelerated Shelf Life Test) method. The results showed that during storage, the water content increased, whereas the fat content decreased. Fat content is a critical variable in determining the shelf life of coffee. The coffee in AF130 packaging has longer shelf life than in AF65 and L144. To extend the shelf life of coffee packaged in AF130 and L144 is best kept at 45<sup> o</sup>C whereas coffee in AF65 packaging  is ideally at 25<sup> o</sup>C.</em></p>

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