scholarly journals Measurement of Off-Flavoring Volatile Compounds and Microbial Load as a Probable Marker for Keeping Quality of Pasteurized Milk

2019 ◽  
Vol 9 (5) ◽  
pp. 959 ◽  
Author(s):  
Anjum Rashid ◽  
Imran Javed ◽  
Barbara Rasco ◽  
Shyam Sablani ◽  
Muhammad Ayaz ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Solid Phase ◽  
Storage Period ◽  
Microbial Load ◽  
Plate Count ◽  
Milk Product ◽  
Pasteurized Milk ◽  
Keeping Quality ◽  
Different Temperatures

(1) Background: Multiple attempts have been conducted to correlate milk keeping quality with chemical, physical or bacteriological parameters. These methods only measure the chemical changes in milk produced by bacteria. Headspace solid-phase micro-extraction (HS-SPME) is an economic and recent method used to measure both volatile compounds and microbial load in milk, also allowing to keep the quality of the milk product. (2) Methods: The present study was conducted to identify and measure the off-flavoring volatile compounds through gas chromatography coupled with flame ionization detector (GC-FID) and the microbial load of pasteurized fluid milk stored at different temperatures, as a possible indicator of its keeping quality. (3) Results: The highest results were obtained to acetone, followed by butanone, pentanal and ethanol. These mean values were significantly enhanced from the 0 to 19th day of storage, at 10 °C. At day 19th, the minimum score for aroma, flavor and overall acceptability were also recorded as 4.33 ± 0.17, 4.02 ± 0.06, 4.00 ± 0.04, respectively. Likewise, maximum values for standard plate count (Log10 CFU 15.54 ± 0.40 mL−1) and total psychotroph count (Log10 CFU 11.67 ± 0.30mL−1) were reported at 10 °C and 4 °C. (4) Conclusion: HS-SPME/GC-FID methodology revealed to be very sensitive and capable to be applied in volatile compounds quantification in pasteurized milk produced during the storage period at different temperatures.

Comparison between the EC plate count test at 21 °C and an accelerated plate count method for assessing the keeping quality of pasteurized milk

1992 ◽  
Vol 59 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Sarah A. Langford ◽  
Rohan G. Kroll
Keyword(s):  
Plate Count ◽  
Gram Negative ◽  
Rapid Methods ◽  
Pasteurized Milk ◽  
Psychrotrophic Bacteria ◽  
Commercial Interest ◽  
Count Method ◽  
Keeping Quality ◽  
Plate Count Method

The keeping quality of properly refrigerated pasteurized milk and cream is primarily determined by post-pasteurization contamination by Gram-negative psychrotrophic bacteria (Phillips et al. 1981; Schröder et al. 1982). Reliable and rapid methods of assessing the levels of contamination by these organisms are therefore of commercial interest.

scholarly journals Effect of Humidity-Controlled Dehydration on Microbial Growth and Quality Characteristics of Fresh Wet Noodles

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 844
Author(s):  
Jun-Jie Xing ◽  
Dong-Hui Jiang ◽  
Zhen Yang ◽  
Xiao-Na Guo ◽  
Ke-Xue Zhu
Keyword(s):  
Shelf Life ◽  
Microbial Growth ◽  
Treatment Time ◽  
Positive Influence ◽  
Quality Characteristics ◽  
Plate Count ◽  
Cooking Properties ◽  
Total Plate Count ◽  
Different Temperatures

Humidity-controlled dehydration (HCD) was innovatively applied in this paper to control the growth of microorganisms in fresh wet noodles (FWN). Effects of HCD treatment with different temperatures (40, 60 or 80 °C), relative humidity (RH, 50%, 70% or 90%) and treatment time (5–32 min) on the total plate count (TPC), the shelf-life, and qualities of FWN were investigated. The results showed that HCD reduced the initial microbial load on the fresh noodles and extended the shelf-life up to 14–15 days under refrigeration temperature (10 °C). A 1.39 log10 CFU/g reduction for the initial TPC was achieved after HCD treatment at the temperature of 60 °C and RH of 90%. HCD with higher RH had a more positive influence on quality improvement. The L* values, the apparent stickiness, and the cooking properties of the noodle body were improved by HCD while good sensory and texture quality of noodles were still maintained after the dehydration process.

scholarly journals Shelf-life of Dahi (Yogurt) with or without potato mash

2012 ◽  
Vol 29 (1) ◽  
pp. 22-30
Author(s):  
M R Amin ◽  
M N Islam ◽  
M A Habib ◽  
F Islam
Keyword(s):  
Shelf Life ◽  
Room Temperature ◽  
Storage Period ◽  
Keeping Quality ◽  
Different Types

Four different types of Dahi (Yogurt) were prepared and kept at room and   refrigeration temperatures with different concentrations of potato mash (0, 5, 10 and 15%). These Dahi samples were analyzed for smell and taste, body and consistency, colour, texture and acidity and pH at pre and post storage period. The quality of Dahi deteriorated quickly at room temperature than at refrigeration temperature. With (5%) or without potato mash keeping quality was preserved for up to three days but at refrigeration temperature they were suitable up to 12 days. Addition of 10% and 15% potato mashes were suitable for keeping Dahi up to two days at room temperature while in refrigeration temperature it was acceptable up to ten and eight days, respectively. Preparation of Dahi in incorporating potato mash may be economically feasible without compromising it qualities. DOI: http://dx.doi.org/10.3329/bvet.v29i1.11886 Bangl. vet. 2012. Vol. 29, No. 1, 22-30 

scholarly journals Fresh Basil Infusion: Effect of Sous-Vide Heat Treatment on Their Volatile Composition Profile, Sensory Profile, and Color

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 5
Author(s):  
Artur Głuchowski ◽  
Ewa Czarniecka-Skubina ◽  
Krzysztof Tambor ◽  
Elvyra Jariené
Keyword(s):  
Heat Treatment ◽  
Volatile Compounds ◽  
Sensory Profile ◽  
Pronounced Change ◽  
Headspace Volatile ◽  
Different Temperatures ◽  
Sous Vide ◽  
Cie Lab ◽  
Area Percentage

Herbs, including basil, are used to enhance the flavor of food products around the world. Its potential is influenced by the quality of fresh herbs and processing practices, wherein conditions of heat treatment play an important role. The aim of the research was to determine the effect of sous-vide heat treatment on the volatile compounds profile, sensory quality, and color of basil infusions. The material used for research was aqueous basil infusion prepared conventionally at 100 °C, and using the sous-vide method (65, 75, and 85 °C). The composition of volatile compounds was identified by GC/MS analysis, the sensory profile was assessed using a group of trained panelists, while the color was instrumentally assessed in the CIE Lab system. No significant differences were found in the intensity of the taste and aroma of basil infusions at different temperatures. Seventy headspace volatile compounds were identified in the analyzed samples, ten of which exceeded 2% of relative area percentage. The most abundant compounds were eucalyptol (27.1%), trans-ocimene (11.0%), β-linalool (9.2%), and β-myrcene (6.7%). Most of the identified compounds belonged to the terpenes and alcohols groups. Our findings show that the conventional herbal infusion was more like a sous-vide infusion prepared at the lowest temperature SV65, while SV75 and SV85 were similar to each other but different from the conventional. However, a smaller number of volatile compounds in the samples heated at higher temperatures of sous-vide were identified. The sous-vide samples showed a higher content of alkanes. The sous-vide method (p ≤ 0.05) resulted in darker, less green, and less yellow basil leaves than fresh and traditionally steeped ones. Long heat treatment under vacuum at higher temperatures causes a pronounced change in the aroma composition.

A Membrane-Filter Technique to Test for the Significance of Sublethally Injured Bacteria in Retail Pasteurized Milk

1975 ◽  
Vol 38 (2) ◽  
pp. 87-88 ◽  
Author(s):  
T. J. CLAYDON
Keyword(s):  
Shelf Life ◽  
Membrane Filter ◽  
Selective Medium ◽  
Pasteurized Milk ◽  
Filter Technique ◽  
Litmus Milk ◽  
Keeping Quality ◽  
Membrane Transfer

A membrane transfer procedure previously described was used to study the possible role of sublethally injured bacteria in the keeping quality of retail pasteurized milk. Trypticase soy broth (TSB) was used as nonselective medium and TSB plus NaCl at pH 6.0 (TSBS 6.0), as the selective medium inhibitory to injured organisms. In pasteurized milk at early stages of storage, colony counts on the latter medium were much lower than on the former. Subsequent transfer of the TSBS 6.0 filters to fresh TSB and further incubation usually increased the counts to about the initial TSB range. Generally the organisms presumed injured and subsequently recovered were the same types as those considered uninjured. They were mainly streptococci and micrococci that produced only slow changes in litmus milk at 5 C, so they are of doubtful significance in the shelf life of retail milk at refrigerator temperatures.

scholarly journals The Keeping Quality of Pasteurized Milk in Home Refrigerators

1949 ◽  
Vol 32 (11) ◽  
pp. 945-949 ◽  
Author(s):  
S.J. Weese ◽  
H.O. Henderson
Keyword(s):  
Pasteurized Milk ◽  
Keeping Quality

scholarly journals Effect of Postharvest Transport and Storage on Color and Firmness Quality of Tomato

Horticulturae ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 163
Author(s):  
Mai Al-Dairi ◽  
Pankaj B. Pathare ◽  
Rashid Al-Yahyai
Keyword(s):  
Weight Loss ◽  
Storage Temperature ◽  
Color Change ◽  
Storage Period ◽  
Color Difference ◽  
Transport Distance ◽  
Transportation Distance ◽  
Different Temperatures ◽  
And Storage

Transport duration affects the vibration level generated which has adverse effects on fresh produce during transportation. Furthermore, temperature affects the quality of fresh commodities during storage. This study evaluated physical changes in tomatoes during transportation and storage. Tomatoes were transported at three distances (100, 154, and 205 km) from a local farm and delivered to the Postharvest Laboratory where vibration acceleration was recorded per distance. Tomato was stored at two different temperatures (10 °C and 22 °C) for 12 days. The physical qualities like weight loss and firmness of all tomato samples were evaluated. RGB image acquisition system was used to assess the color change of tomato. The results of vibration showed that over 40% of accelerations occurred in the range of 0.82–1.31 cm/s2 of all transport distances. Physical quality analyses like weight loss and firmness were highly affected by transportation distance, storage temperature, and storage period. The reduction in weight loss and firmness was the highest in tomatoes transported from the farthest distance and stored at 22 °C. Lightness, yellowness, and hue values showed a high reduction as transport distance increased particularly in tomatoes stored at 22 °C. Redness, total color difference, and color indices increased significantly on tomatoes transported from 205 km and stored at 10 °C and 22 °C. The study indicated that the increase in transportation distance and storage temperature cause higher changes in the physical qualities of tomatoes.

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