scholarly journals Microbiological and physicochemical changes during ripening in Bulgarian white brined cheese made from raw cow milk

2020 ◽  
Vol 23 (4) ◽  
pp. 494-503
Author(s):  
D. Bangieva
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Titratable Acidity ◽  
Chloride Content ◽  
Raw Milk ◽  
Cow Milk ◽  
Microbiological Analysis ◽  
Physicochemical Changes ◽  
Raw Milk Cheese

The main microbiological hazards of raw milk cheese are associated with Listeria monocytogenes, Escherichia coli and Staphylococcus aureus. Due to its high nutritional value, cheese is an excellent medium for the growth of these pathogens. This study was aimed to observe microbial dynamics of Bulgarian white brined cheese during cheese production and ripening. Microbiological analysis included determination of Staphylococcus aureus, Listeria spp. and Escherichia coli counts. Some physicochemical parameters, such as total titratable acidity, sodium chloride content, water activity and pH were also examined. Results revealed statistically significant increase in bacterial counts after cheesemaking steps and decrease at the end of the ripening period. Listeria monocytogenes was not detected in any of the cheese samples. Raw milk cheese was of unsatisfactory quality that emphasises the need for applying and maintaining good hygiene practices along the food chain to prevent microbial contamination and growth

Growth of Listeria monocytogenes, Salmonella spp., Escherichia coli O157:H7, and Staphylococcus aureus on Cheese during Extended Storage at 25°C

2014 ◽  
Vol 77 (8) ◽  
pp. 1275-1288 ◽  
Author(s):  
WAN MEI LEONG ◽  
RENAE GEIER ◽  
SARAH ENGSTROM ◽  
STEVE INGHAM ◽  
BARBARA INGHAM ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Water Activity ◽  
Titratable Acidity ◽  
Study Data ◽  
Escherichia Coli O157 ◽  
Salmonella Spp ◽  
Require Time ◽  
And Staphylococcus Aureus

Potentially hazardous foods require time/temperature control for safety. According to the U.S. Food and Drug Administration Food Code, most cheeses are potentially hazardous foods based on pH and water activity, and a product assessment is required to evaluate safety of storage >6 h at 21°C. We tested the ability of 67 market cheeses to support growth of Listeria monocytogenes (LM), Salmonella spp. (SALM), Escherichia coli O157:H7 (EC), and Staphylococcus aureus (SA) over 15 days at 25°C. Hard (Asiago and Cheddar), semi-hard (Colby and Havarti), and soft cheeses (mozzarella and Mexican-style), and reduced-sodium or reduced-fat types were tested. Single-pathogen cocktails were prepared and individually inoculated onto cheese slices (~105 CFU/g). Cocktails were 10 strains of L. monocytogenes, 6 of Salmonella spp., or 5 of E. coli O157:H7 or S. aureus. Inoculated slices were vacuum packaged and stored at 25°C for ≤15 days, with surviving inocula enumerated every 3 days. Percent salt-in-the-moisture phase, percent titratable acidity, pH, water activity, and levels of indigenous/starter bacteria were measured. Pathogens did not grow on 53 cheeses, while 14 cheeses supported growth of SA, 6 of SALM, 4 of LM, and 3 of EC. Of the cheeses supporting pathogen growth, all supported growth of SA, ranging from 0.57 to 3.08 log CFU/g (average 1.70 log CFU/g). Growth of SALM, LM, and EC ranged from 1.01 to 3.02 log CFU/g (average 2.05 log CFU/g), 0.60 to 2.68 log CFU/g (average 1.60 log CFU/g), and 0.41 to 2.90 log CFU/g (average 1.69 log CFU/g), respectively. Pathogen growth varied within cheese types or lots. Pathogen growth was influenced by pH and percent salt-in-the-moisture phase, and these two factors were used to establish growth/no-growth boundary conditions for safe, extended storage (≤25°C) of pasteurized milk cheeses. Pathogen growth/no-growth could not be predicted for Swiss-style cheeses, mold-ripened or bacterial surface–ripened cheeses, and cheeses made with nonbovine milk, as insufficient data were gathered. This challenge study data can support science-based decision making in a regulatory framework.

Staphylococcus aureus and Listeria monocytogenes in Norwegian raw milk cheese production

2011 ◽  
Vol 28 (3) ◽  
pp. 492-496 ◽  
Author(s):  
Ragnhild Aakre Jakobsen ◽  
Ragna Heggebø ◽  
Elin Bekvik Sunde ◽  
Magne Skjervheim
Keyword(s):  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Raw Milk ◽  
Raw Milk Cheese ◽  
Cheese Production

Effect of Pretreatment of Milk Quality Characteristics of Jibna-Beida (White Cheese)

2007 ◽  
Vol 3 (4) ◽  
Author(s):  
Abdel Moneim El-Hadi Sulieman
Keyword(s):  
Heat Treatment ◽  
Raw Milk ◽  
Quality Characteristics ◽  
Soluble Solids ◽  
Cow Milk ◽  
Microbiological Analysis ◽  
Total Soluble Solids ◽  
White Cheese ◽  
Raw Milk Cheese ◽  
Microbial Groups

The objective of this study was to investigate the effect of heat treatment of milk on the quality characteristics of Jibna-beida (white cheese). The heat treatment methods used included pasteurization of cow milk at 65oC for 30 min, and boiling of cow milk at 102oC for 15 min. The microbiological analysis indicated that raw milk contained high counts of total viable microbes, coliforms, staphylococci, yeast and mould. However, all these microbial groups were highly reduced in pasteurized and boiled milk. Jibna–beida was prepared using the three types of milk: raw, pasteurized and boiled. The raw milk cheese contained: 43.0% moisture, 12.5% ash, 20.16% protein and 56.48% total soluble solids, while the pasteurized milk cheese contained: 50.9% moisture, 10.5% ash, 17.63% protein and 48.76% total soluble solids and the boiled milk cheese contained: 48.5% moisture, 13.4% ash, 15.4% protein and 55.75% total soluble solids. During storage, the pH of all cheese samples decreased and the acidity increased. The microbiological analysis of the three types of cheese indicated that the microbial load of raw milk cheese was higher when compared with those of pasteurized and boiled milk cheeses. The sensory evaluation revealed acceptance of the three types of cheeses with preference to the raw milk cheese than the other two types of cheese.

scholarly journals Behaviour of Listeria monocytogenes and Escherichia coli O157:H7 during the cheese making of traditional raw-milk cheeses from Italian Alps

2015 ◽  
Vol 4 (2) ◽  
Author(s):  
Elena Cosciani-Cunico ◽  
Elena Dalzini ◽  
Stefania Ducoli ◽  
Chiara Sfameni ◽  
Barbara Bertasi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Raw Milk ◽  
Starter Cultures ◽  
Cow Milk ◽  
Italian Alps ◽  
Cheese Making ◽  
E Coli ◽  
Food Borne ◽  
First Time

The behaviour of <em>Listeria monocytogenes</em> and <em>Escherichia coli</em> O157:H7 was studied during the manufacture and ripening of two traditional Italian Alps cheeses. Each cheese type was manufactured in a pilot plan from raw cow milk (without the addition of starter cultures) artificially inoculated with <em>L. monocytogenes</em> and <em>E. coli</em> O157:H7 to a final concentration of about 4 log CFU/mL. The pathogens were enumerated throughout the cheese making and ripening processes to study their behaviour. When the milk was inoculated with 4 Log CFU/mL, the pathogens counts increased in the first time during the manufacturing process and then remained constant, until the end of ripening, or decreased significantly. Results indicate that the environment and nature of food borne pathogens affected the concentration of the bacteria during the manufacturing and ripening process. Thus, the presence of low cells numbers of <em>L. monocytogenes</em> and <em>E. coli</em> O157:H7 in milk destined for the production of raw milk cheeses characterized by a cooking of the curd less than 48°C can constitute a hazard for the consumer.

Behaviour of Listeria monocytogenes and Staphylococcus aureus in sliced, vacuum-packaged raw milk cheese stored at two different temperatures and time periods

2016 ◽  
Vol 57 ◽  
pp. 15-19 ◽  
Author(s):  
Alberto Bellio ◽  
Sara Astegiano ◽  
Amaranta Traversa ◽  
Daniela Manila Bianchi ◽  
Silvia Gallina ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Raw Milk ◽  
Different Temperatures ◽  
Time Periods ◽  
Raw Milk Cheese ◽  
And Staphylococcus Aureus

scholarly journals The hygienic quality of raw reindeer milk

Rangifer ◽  
2004 ◽  
Vol 24 (2) ◽  
pp. 67-70 ◽  
Author(s):  
Joanna Kurki ◽  
Anna Pitkälä ◽  
Mauri Nieminen
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Bacillus Cereus ◽  
Raw Milk ◽  
Total Bacterial Count ◽  
Coagulase Negative Staphylococci ◽  
Bulk Milk ◽  
Hygienic Quality

The somatic cell count (SCC) and total bacterial count (TBC) as well as the presence of major food-borne pathogens and udder pathogens in reindeer raw milk were studied. Two groups of 4 female reindeer were milked on alternate days for six weeks. A milk sample from each quarter was taken before milking and of the bulk milk at the end of milking. Micrococcus sp. was observed in one, Staphylococcus aureus in one and coagulase-negative staphylococci in five of the quarter samples (n=318). In the bulk milk (n=19) TBC varied between 700 and 1 700 000 cfu (colony forming units)/ml and SCC between 52 000 and 183 000 cells/ml. No Bacillus cereus, S. aureus or Listeria monocytogenes were detected in the bulk milk, but Escherichia coli and Enterobacteriaceae were found in 5 bulk milk samples. According to the bacteriological examination the udder health of the reindeer was good. Indicative information on the SCC of healthy reindeer was obtained. None of the common potential food-poisoning bacteria were found in raw milk. There was great variation in the bulk milk TBC and the average TBC was rather high (ca. 300 000 cfu/ml). The hygienic quality of raw reindeer milk makes it well suited for food manufacture. However, the results indicate that the milking conditions may be crucial for the quality of raw milk.Abstract in Finnish / Yhteenveto:Tutkimuksen kohteena oli poron raakamaidon solupitoisuus ja kokonaispesäkeluku sekä tärkeimpien elintarvike- ja utarepatogeenien esiintyminen raakamaidossa. Kaksi 4 vaatimen ryhmää lypsettiin vuoropäivinä 6 viikon ajan. Ennen lypsyä vaatimista otettiin vedinkohtaiset näytteet ja lypsyn päätyttyä näyte yhteismaidosta. Micrococcus sp. todettiin yhdessä, Staphylococcus aureus yhdessä ja koagulaasinegatiivisia stafylokokkeja viidessä vedinkohtaisessa näytteessä (n=318). Yhteismaitonäytteiden (n=19) kokonaispesäkeluvut vaihtelivat välillä 700-1 700 000 pmy (pesäkkeitä muodostava yksikkö)/ml ja somaattisten solujen määrät välillä 52 000-183 000 kpl/ml. Yhteismaitonäytteissä ei todettu Bacillus cereus-, S. aureus- eikä Listeria monocytogenes -bakteereita, mutta viidessä näytteessä todettiin Enterobacteriaceae-heimon bakteereita ja Escherichia coli -bakteereita. Bakteeriviljelyjen perusteella vaadinten utareterveys oli hyvä. Terveiden vaadinten maidon solupitoisuudesta saatiin suunta-antavaa tietoa. Raakamaidossa ei todettu yleisimpiä potentiaalisia ruokamyrkytysten aiheuttajia. Yhteismaidon kokonaispesäkeluvuissa esiintyi suurta vaihtelua ja niiden keskiarvo oli melko korkea (n. 300 000 pmy/ml). Poron raakamaito on hygieeniseltä laadultaan hyvää elintarvikkeiden raakaainetta. Tulokset antavat kuitenkin viitteitä, että itse lypsytapahtuma on porollakin avainasemassa raakamaidon laatuun vaikuttavana tekijänä.

scholarly journals Autophagy—A Story of Bacteria Interfering with the Host Cell Degradation Machinery

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 110
Author(s):  
Anna K. Riebisch ◽  
Sabrina Mühlen ◽  
Yan Yan Beer ◽  
Ingo Schmitz
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Immune Response ◽  
Mycobacterium Tuberculosis ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Innate Immune ◽  
Intracellular Pathogens ◽  
Response Mechanism ◽  
Pathogenic Escherichia Coli

Autophagy is a highly conserved and fundamental cellular process to maintain cellular homeostasis through recycling of defective organelles or proteins. In a response to intracellular pathogens, autophagy further acts as an innate immune response mechanism to eliminate pathogens. This review will discuss recent findings on autophagy as a reaction to intracellular pathogens, such as Salmonella typhimurium, Listeria monocytogenes, Mycobacterium tuberculosis, Staphylococcus aureus, and pathogenic Escherichia coli. Interestingly, while some of these bacteria have developed methods to use autophagy for their own benefit within the cell, others have developed fascinating mechanisms to evade recognition, to subvert the autophagic pathway, or to escape from autophagy.

scholarly journals ATIVIDADE ANTIMICROBIANA DE MICRORGANISMOS ISOLADOS DE GRÃOS DE KEFIR

2018 ◽  
Vol 19 (0) ◽  
Author(s):  
Priscila Alves Dias ◽  
Daiani Teixeira Silva ◽  
Cláudio Dias Timm
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Salmonella Enterica ◽  
Escherichia Coli O157 ◽  
E Coli

Resumo Kefir é o produto da fermentação do leite pelos grãos de kefir. Esses grãos contêm uma mistura simbiótica de bactérias e leveduras imersas em uma matriz composta de polissacarídeos e proteínas. Muitos benefícios à saúde humana têm sido atribuídos ao kefir, incluindo atividade antimicrobiana contra bactérias Gram positivas e Gram negativas. A atividade antimicrobiana de 60 microrganismos isolados de grãos de kefir, frente à Escherichia coli O157:H7, Salmonella enterica subsp. enterica sorotipos Typhimurium e Enteritidis, Staphylococcus aureus e Listeria monocytogenes, foi estudada através do teste do antagonismo. A ação antimicrobiana dos sobrenadantes das bactérias ácido-lácticas que apresentaram atividade no teste do antagonismo foi testada. O experimento foi repetido usando sobrenadantes com pH neutralizado. Salmonella Typhimurium e Enteritidis sobreviveram por 24 horas no kefir em fermentação. E. coli O157:H7, S. aureus e L. monocytogenes foram recuperados até 72 horas após o início da fermentação. Todos os isolados apresentaram atividade antimicrobiana contra pelo menos um dos patógenos usados no teste do antagonismo. Sobrenadantes de 25 isolados apresentaram atividade inibitória e três mantiveram essa atividade com pH neutralizado. As bactérias patogênicas estudadas sobreviveram por tempo superior àquele normalmente utilizado para a fermentação do kefir artesanal, o que caracteriza perigo em potencial para o consumidor quando a matéria-prima não apresentar segurança sanitária. Lactobacillus isolados de grãos de kefir apresentam atividade antimicrobiana contra cepas de E. coli O157:H7, Salmonella sorotipos Typhimurium e Enteritidis, S. aureus e L. monocytogenes além daquela exercida pela diminuição do pH.

scholarly journals Enterotoxin-producing Staphylococcus aureus genotype B as a major contaminant in Swiss raw milk cheese

2014 ◽  
Vol 97 (3) ◽  
pp. 1305-1312 ◽  
Author(s):  
J. Hummerjohann ◽  
J. Naskova ◽  
A. Baumgartner ◽  
H.U. Graber
Keyword(s):  
Staphylococcus Aureus ◽  
Raw Milk ◽  
Raw Milk Cheese
Sign in / Sign up

Export Citation Format

Share Document