scholarly journals Evaluating the shelf-life of pasteurized milk in Oman

Heliyon ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. e06555
Author(s):  
M. Al-Farsi ◽  
I. Al-Gharibi ◽  
A. Al-Abri ◽  
A. Al-Humaimi ◽  
F. Al-Nabhani ◽  
...  
Keyword(s):  
Shelf Life ◽  
Pasteurized Milk

Heat-Resistant Psychrotrophic Bacteria Isolated from Pasteurized Milk1

1977 ◽  
Vol 40 (2) ◽  
pp. 101-108 ◽  
Author(s):  
C. J. WASHAM ◽  
H. C. OLSON ◽  
E. R. VEDAMUTHU
Keyword(s):  
Thermal Resistance ◽  
Shelf Life ◽  
Detailed Examination ◽  
Genus Bacillus ◽  
Pasteurized Milk ◽  
Psychrotrophic Bacteria ◽  
Milk Samples ◽  
Heat Resistant ◽  
Different Types

Psychrotrophic bacteria were isolated from 227 pasteurized milk samples which had a shelf life in excess of 20 days at 7.2 C. Of 700 cultures isolated, 135 were resistant to heating at 72 C for 16 sec and were able to re-establish growth at 7.2 C. Thirty-five cultures, representing 15 different types were subjected to detailed examination to determine their actions on refrigerated milk, growth temperatures, thermal resistance at various temperatures, and their identities. The spore-forming genus Bacillus occured most frequently. The non-sporing types were assigned to the genera Arthrobacter, Microbacterium, Streptococcus, and Corynebacterium.

Effect of Light on Vitamin Loss and Shelf Life of Pasteurized Milk Packaged in PET Bottles

2012 ◽  
pp. 21-35
Author(s):  
Michael Kontominas ◽  
Anastasia Badeka ◽  
Nikolaos Pournis ◽  
Ioannis Karabagias
Keyword(s):  
Shelf Life ◽  
Pasteurized Milk ◽  
Pet Bottles ◽  
Effect Of Light

scholarly journals Spoilage potential of spore-forming bacteria from refrigerated raw milk

2018 ◽  
Vol 39 (5) ◽  
pp. 2049 ◽  
Author(s):  
José Carlos Ribeiro Júnior ◽  
Ronaldo Tamanini ◽  
André Luís Martinez de Oliveira ◽  
Juliane Ribeiro ◽  
Vanerli Beloti
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Shelf Life ◽  
Lipolytic Activity ◽  
Raw Milk ◽  
Rrna Gene ◽  
16S Rrna Gene Analysis ◽  
Pasteurized Milk ◽  
Bacillus Spp ◽  
Aerobic Spores

Aerobic bacterial spores are an important group of microorganisms in raw milk. These microbes are thermoduric, whereas the vegetative forms are thermophilic, thermoduric and psychrotrophic and reduce the shelf life of pasteurized milk. In Brazil, there are a lack of studies on the load of aerobic spores in raw milk; thus, little is known about the spoilage activity of these organisms. The aim the present study was to quantify the aerobic spores in Brazilian refrigerated raw milk of dairy region of Castro, Paraná state, assess the potential proteolytic and/or lipolytic isolates and identify the microorganisms derived from the germination. Twenty milk samples were evaluated, and the aerobic spore count was performed after plating the samples following heat treatment at 80°C for 12 min. The activity proteolytic and lipolytic isolates were evaluated through subculture on milk agar and tributyrin agar, respectively, and these microorganisms were identified using partial 16S rRNA gene sequences that were compared through GenBank. The aerobic spore counts ranged from 1 to 3.7 log CFU.mL-1, with a mean of 1.75 (± 0.59) log CFU.mL-1. After spore germination, 137 aerobic bacterial isolates were obtained, 40 of which (29.2%) showed milk spoilage activity. Among these, 31 isolates (77.5%) were proteolytic and lipolytic, seven isolates (17.5%) were exclusively lipolytic and two isolates (5%) were only proteolytic. Based on the 16S rRNA gene analysis, Bacillus licheniformis (55%), Bacillus spp. (27.5%), Paenibacillus spp. (7.5%), Bacillus pumilus (5%), Bacillus circulans (2.5%) and Brevibacillus spp. (2.5%) were identified. Studies of Brazilian raw milk microbiota have not yet described B. circulans which are frequently detected in milk from other countries. Among the 22 B. licheniformis isolates, 21 microbes (95.5%) showed proteolytic and lipolytic activity, and one isolate (4.5%) exhibited only proteolytic activity. The two B. pumilus isolates were proteolytic and lipolytic, whereas the B. circulans isolate was only lipolytic. Among the 11 Bacillus spp. isolates, eight isolates (72.7%) were proteolytic and lipolytic, one isolate (9.1%) was proteolytic and the other two isolates (18.2%) were lipolytic. The three Paenibacillus spp. and Brevibacillus spp. isolates were primarily lipolytic. Therefore, to extend the shelf life of pasteurized milk, preventive measures must be adopted to reduce contamination with spores because one-third of these microorganisms exhibited proteolytic and/or lipolytic activity.

scholarly journals Influence of the microbiological quality of raw milk on the shelf life of pasteurized milk

2019 ◽  
Vol 40 (4) ◽  
pp. 1469
Author(s):  
José Carlos Ribeiro Júnior ◽  
Aline Marangon de Oliveira ◽  
Fernando Godoi Silva ◽  
Lorena Natalino Haber Garcia ◽  
Cátia Maria de Oliveira Lobo ◽  
...  
Keyword(s):  
Shelf Life ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Poor Quality ◽  
Pasteurized Milk ◽  
Microbial Counts ◽  
Legal Standards ◽  
Milk Samples ◽  
Brazilian Standard

The dairy industry strives to produce high quality products with high nutritional value as well as to meet the legal standards for longer shelf life. However, these goals are made unfeasible by the poor quality of raw milk produced in some regions of Brazil. Others Brazilian dairy regions, however, already succeed in producing milk with low microbial counts, such as the municipality of Castro, Paraná state, designated as the ‘Brazilian dairy capital’. In order to evaluate the effect of raw milk quality on microbial counts during the shelf life of pasteurized milk, samples were collected from two dairy regions of Paraná: the northern and Castro region, characterized by milk production with high and low microbiological counts, respectively. Samples were experimentally pasteurized and the total microorganism counts were analyzed for 18 days at 7°C, using the Brazilian standard microbiological count limit for pasteurized milk (8 x 104 CFU/mL) as the end of the shelf life. Low microbiological counts in raw milk (Castro) resulted in significantly lower counts shortly after pasteurization and over the entire shelf life, meeting the pasteurized milk standard for 18 days. The temporal evolution in the counts over 18 days for the milks of high and low microbiological count was similar; however, the disparity between the absolute counts between the regions was significant (p < 0.05). Of the milk samples from northern Paraná, four (44.4%) already had counts higher than that of the legislative limit for pasteurized milk immediately after pasteurization. The others (five) reached the maximum microbiological count limit for pasteurized milk on the 6th day after pasteurization. In contrast, the milk from the Castro region remained below the limit throughout the analysis period. Thus, it can be stated that the microbiological quality of raw milk is directly related to the initial count of microorganisms after pasteurization, and that pasteurized milk produced from raw milk with low microbiological counts complies with the Brazilian legislation for 18 days following thermal processing.

Origins and levels of post pasteurization contamination of milk in the dairy and their effects on keeping quality

1984 ◽  
Vol 51 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Monika J. A. Schröder
Keyword(s):  
Shelf Life ◽  
Considerable Influence ◽  
Gram Negative ◽  
Pasteurized Milk ◽  
Wide Range ◽  
Keeping Quality ◽  
Before And After ◽  
Milk Feeding

SummaryBacterial post pasteurization contamination with psychrotrophic Gram-negative rods (GNR) was measured in commercial milks before and after transfer to retail containers. The tanks of pasteurized milk feeding the filling units contaminated milk less often (39% of samples) but usually at a higher level than the filling units (92% of samples). The number of GNR present had a considerable influence on the shelf life of milk, and the range found in commercially pasteurized milk was reflected in a wide range of shelf lives.

Molecular Analysis of Spoilage-Related Bacteria in Pasteurized Milk during Refrigeration by PCR and Denaturing Gradient Gel Electrophoresis

2009 ◽  
Vol 72 (3) ◽  
pp. 572-577 ◽  
Author(s):  
HONGFEI HE ◽  
JIN DONG ◽  
CHIN NYEAN LEE ◽  
YONG LI
Keyword(s):  
Shelf Life ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Plate Count ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Gradient Gel Electrophoresis ◽  
Aerobic Plate Count ◽  
Species Specific

Bacterial diversity in fluid milk products has been extensively studied in order to improve milk quality. Here, we illustrate the utility of viable counts and PCR–denaturing gradient gel electrophoresis (DGGE) for monitoring the microbial spoilage of pasteurized milk during shelf life. Five pasteurized milk samples stored at 4°C were examined at 10 and 5 days before expiration and on the expiration day. With bacterial DNA extracted directly from the samples, PCR-DGGE analysis indicated that Pseudomonas became dominant in four samples. Meanwhile, the aerobic plate count of these four samples exceeded the regulatory limit of 20,000 CFU/ml at 5 days before expiration, and the rapid psychrotrophic count markedly surpassed the aerobic plate count on the expiration day. Streptococcus and Buttiauxella spp. were detected in several samples. Sequence analysis of DGGE fragments revealed high diversity among Pseudomonas spp. in the milk samples. P. putida and P. migulae grew to high numbers during refrigerated storage. Further identification of Pseudomonas at the species level was facilitated by PCR and multiplex PCR using species-specific primers; consequently, P. fluorescens and P. fragi were observed. These results highlight an important role of Pseudomonas in the shelf life of pasteurized milk.

Microbiological Shelf Life of Pasteurized Milk in Bottle and Pouch

2010 ◽  
Vol 75 (1) ◽  
pp. M36-M40 ◽  
Author(s):  
R.R. Petrus ◽  
C.G. Loiola ◽  
C.A.F. Oliveira
Keyword(s):  
Shelf Life ◽  
Pasteurized Milk

scholarly journals Proteolytic and lipolytic microbiota of refrigerated raw milk from northeast and southern regions of Brazil

2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4289 ◽  
Author(s):  
Jose Carlos Ribeiro Junior ◽  
Joyce Bitencourt Atayde Lima ◽  
Kleydejany Lima de Lemos ◽  
Livia Cavaletti Corrêa da Silva ◽  
Ronaldo Tamanini ◽  
...  
Keyword(s):  
Shelf Life ◽  
Microbiological Quality ◽  
Raw Milk ◽  
The State ◽  
Advanced Technology ◽  
Daily Production ◽  
Pasteurized Milk ◽  
Hygiene Practices ◽  
Spoilage Microorganisms

<p>The shelf life of milk and milk derivatives is directly related to the microbiological quality of refrigerated raw milk. Spoilage microorganisms with proteolytic and/or lipolytic properties are primarily responsible for the decrease in the quality of milk, which is reflected in the shelf life of pasteurized milk and all derivatives. The aim of this study was to determine the spoilage microbial load of refrigerated raw milk from the northeast and southern regions of Brazil, which have different climatic and technological conditions of production. We evaluated 46 samples of milk from the state of Paraná in the southern region, and 10 samples of milk from the state of Maranhão in the northeast region, totaling 56 samples collected from November 2013 to November 2014. The producers of Paraná were divided into large (20) or small (26) according to the average daily production. All producers of Maranhão were considered small (&lt;500L/day). The proteolytic and lipolytic microorganism counts were conducted in milk agar and tributyrin agar, respectively. Milk from the large producers of Paraná had average counts of 1.4 × 104 CFU/mL for proteolytic microorganisms and 1.2 × 103 CFU/mL for lipolytics microorganisms, significantly (p &lt;0.05) lower than the small producers in the same state, and the producers of Maranhão. Producers of Maranhao had counts of 1.1 × 105 CFU/mL for proteolytic microorganisms and 2 × 105 CFU/mL for lipolytic microorganisms, with the proteolytic count significantly lower than that of small Paraná producers. The amount of proteolytic and lipolytic spoilage microorganisms in milk is influenced by the adaptation of the microorganisms to cold, promoted by the cooling of milk, which is practiced less frequently in the country’s northeastern region. The amount of spoilage microorganisms is also affected by the implementation of milking hygiene practices, which reduce contamination. Such practices are more frequently and efficiently implemented among large producers with more advanced technology, which can improve the microbiological quality of raw milk, thus increasing the shelf life of pasteurized milk, and reducing problems in UHT milk as well as milk derivatives. </p>

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