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
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):  

1977 ◽  
Vol 40 (2) ◽  
pp. 101-108 ◽  
Author(s):  
C. J. WASHAM ◽  
H. C. OLSON ◽  
E. R. VEDAMUTHU

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.


2018 ◽  
Vol 39 (5) ◽  
pp. 2049 ◽  
Author(s):  
José Carlos Ribeiro Júnior ◽  
Ronaldo Tamanini ◽  
André Luís Martinez de Oliveira ◽  
Juliane Ribeiro ◽  
Vanerli Beloti

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.


Author(s):  
PATRICIA PRATI ◽  
ROBERTO HERMÍNIO MORETTI ◽  
HELENA MARIA ANDRÉ BOLINI CARDELLO ◽  
ANA LOURDES NEVES GÂNDARA

O objetivo desta pesquisa foi estudar a vida-de-prateleira de produto elaborado com garapa, parcialmente clarificadaestabilizada, e suco de maracujá (5%). A mistura foi adicionada de antioxidante, conservante e espessante em concentrações pré-estabelecidas. Após pasteurização, o produto foi resfriado, embalado em garrafas de polietileno tereftalato (PET) e armazenado sob refrigeração pelo período de um mês. Foram realizadas determinações microbiológicas (Contagem Padrão, Contagem de Bolores e Leveduras, Coliformes Totais e Fecais), físico-químicas (pH, ºBrix, acidez, relação Brix/Acidez, teor de ácido ascórbico, turbidez), e sensoriais. Os resultados da análise sensorial, considerados os mais relevantes para a pesquisa, indicaram que o produto (mistura de garapa parcialmente clarificadaestabilizada com suco de maracujá) pode ser elaborado e comercializado por até quinze dias sob refrigeração, pois as condições do processo permitiram a manutenção da qualidade microbiológica e sensorial. O teor de ácido ascórbico manteve-se em bom nível até o final da estocagem, com perda de apenas 20% em relação ao teor adicionado. SHELF-LIFE STUDY OF A BEVERAGE ELABORATE BY BLEND OF PARTIALLY CLARIFIED-STABILIZED SUGAR-CANE JUICE AND NATURAL PASSION FRUIT JUICE Abstract The objective of this research was to study the shelf-life of a product elaborated with sugar cane juice, partially clarified-stabilized, and passion-fruit juice (5%). The blend was added of antioxidant, preservative and thickener in pre-established concentration. After pasteurization the product was refrigerated in polyethylene teraftalate (PET) bottles and stored for 1 month period under refrigeration. Microbiological determinations (Standard Count, Mould and Yeasts Count, Total and Faecal Coliforms), physico-chemical (ºBrix, pH, acidity, relation Brix/acidity, ascorbic acid content, turbidity) and sensorial were accomplished. The results of sensorial analysis, considered the more relevant for the research, indicated that the product (blend of sugar-cane juice partially clarified/stabilized with passion fruit juice) may be elaborated and commercialized until 15 days under refrigeration, because the conditions of the process allowed the maintenance of microbiological and sensorial quality. Ascorbic acid content maintained a good level until the end of storage, with lost of only 20% in relation to the concentration added.


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 ◽  
...  

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.


1984 ◽  
Vol 51 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Monika J. A. Schröder

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.


2009 ◽  
Vol 72 (3) ◽  
pp. 572-577 ◽  
Author(s):  
HONGFEI HE ◽  
JIN DONG ◽  
CHIN NYEAN LEE ◽  
YONG LI

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.


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

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