Growth ofMycobacterium aviumsubsp.paratuberculosis,Escherichia coli, andSalmonellaEnteritidis during Preparation and Storage of Yogurt

Cirone, Karina Mariela; Huberman, Yosef Daniel; Morsella, Claudia; Méndez, Laura; Jorge, María Cristina; Paolicchi, Fernando Alberto

doi:10.1155/2013/247018

Cited by 11 publications

(8 citation statements)

References 29 publications

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“…In the same context, Osaili et al (18) reported a large increase of E. coli O157:H7 count of 3.05 log CFU mL -1 during the fermentation process. After the fermentation process, we found similar results as Ogwaro et al (20) and Cirone et al (21) , who reported an increase of E. coli O157:H7 counts from 5 CFU mL -1 to 8-9 log CFU mL -1 and 5.3 CFU mL -1 to 6.4 log CFU mL -1 after 24 h of fermentation, respectively.…”

Section: Resultssupporting

confidence: 89%

Escherichia coli O157:H7 SURVIVAL IN TRADITIONAL AND LOW LACTOSE YOGURT DURING FERMENTATION AND COOLING PERIODS

et al. 2017

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The purpose of this study was to evaluate the behavior of E. coli O157:H7 during lactose hydrolysis and fermentation of traditional and low lactose yogurt. It also aimed to verify E. coli O157:H7 survival after 12 h of storage at 4 °C ±1 °C. Two different types of yogurts were prepared, two with whole milk and two with pre-hydrolyzed whole milk; in both groups one yogurt was inoculated with E. coli O157:H7 and the other one was not inoculated. The survival of E. coli and pH of yogurt were determined during fermentation and after 12-h refrigeration. The results showed that E. coli O157:H7 was able to grow during the fermentation period (from 4.34 log CFU.mL -1 to 6.13 log CFU.mL -1 in traditional yogurt and 4.34 log CFU.mL -1 to 6.16 log CFU.mL -1 in low lactose yogurt). The samples with E. coli O157:H7 showed gas formation and syneresis. Thus, E. coli O157:H7 was able to survive and grow during fermentation of traditional and low lactose yogurts affecting the manufacture technology. Moreover, milk contamination by E. coli before LAB addition reduces the growth of L. bulgaricus and S. thermophilus especially when associated with reduction of lactose content Keywords: β-galactosidase; EHEC; fermented milk; lactic acid bacteria; lactose hydrolysis. ResumoObjetivou-se no presente estudo avaliar o comportamento da E. coli O157:H7 durante o processo de hidrólise da lactose e fermentação de iogurte tradicional e com teor reduzido de lactose. Além disso, objetivou-se verificar a viabilidade da E. coli O157:H7 e a viabilidade das bactérias ácido láticas após 12 h de estocagem a 4 °C ±1 °C. Dois diferentes tipos de iogurte com amostras controle e amostras inoculadas foram preparados, sendo dois com leite integral e dois com leite integral pré-hidrolisado; em ambos os grupos um foi inoculado com E. coli O157:H7 e um não foi inoculado. A 2 Cienc. anim. bras., Goiânia, v.18, 1-9, e-39554, 2017Escherichia coli O157:H7 survival in traditional and low lactose yogurt during fermentation sobrevivência da E. coli e o pH dos iogurtes foram determinados durante a fermentação e após 12h de refrigeração. A partir dos resultados observou-se que a E. coli O157:H7 foi capaz de se multiplicar ou manter-se viável durante a fermentação (4,34 UFC.mL -1 para 6,13 UFC.mL -1 no iogurte tradicional e 4,34 UFC.mL -1 para 6,16 log UFC.mL -1 em iogurte com lactose reduzida). Nas amostras inoculadas com E. coli O157:H7 houve formação de gás e sinérese. Dessa forma, concluiu-se que a E. coli O157:H7 foi capaz de sobreviver e de se multiplicar durante a fermentação afetando a tecnologia de fabricação. Além disso, a contaminação do leite antes da adição das BAL reduziu o crescimento de L. bulgaricus e S. thermophilus, especialmente quando associado à redução da lactose. Palavras-chave: β-galactosidase; bactérias ácido láticas; EHEC; hidrólise da lactose; leite fermentado.

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Section: Resultssupporting

confidence: 89%

Escherichia coli O157:H7 SURVIVAL IN TRADITIONAL AND LOW LACTOSE YOGURT DURING FERMENTATION AND COOLING PERIODS

et al. 2017

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“…An inactivation of pathogenic bacteria in fermented dairy products, including yogurt, has been observed in many studies (Rubin and Vaughan 1979, Rubin et al 1982, Alm 1983, Kotz et al 1990, Issa and Ryser 2000, Hlvarez-Ordóñ ez et al 2013, Cirone et al 2013. The main mechanism of bactericidal effect of yogurt on foodborne pathogens seems to be the decline in pH due to lactose fermentation by Lactobacillus delbrueckii ssp.…”

Section: Discussionmentioning

confidence: 96%

“…pH, competitive microflora), storage conditions (temperature) and other environmental circumstances. Cirone et al (2013) proved that pathogenic bacteria like Mycobacterium avium subsp. paratuberculosis, E. coli, and S. Enteritidis could survive the fermentation process during yogurt production and were not inactivated by low pH levels followed by cold storage for at least 20 days.…”

Section: Introductionmentioning

confidence: 99%

Modeling the effect of temperature on survival rate of Listeria monocytogenes in yogurt

Szczawinski¹,

Me²,

Łobacz³

et al. 2016

Polish Journal of Veterinary Sciences

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The aim of the study was to (i) evaluate the behavior of Listeria monocytogenes in a commercially produced yogurt, (ii) determine the survival/inactivation rates of L. monocytogenes during cold storage of yogurt and (iii) to generate primary and secondary mathematical models to predict the behavior of these bacteria during storage at different temperatures.The samples of yogurt were inoculated with the mixture of three L. monocytogenes strains and stored at 3, 6, 9, 12 and 15 o C for 16 days. The number of listeriae was determined after 0, 1, 2, 3, 5, 7, 9, 12, 14 and 16 days of storage. From each sample a series of decimal dilutions were prepared and plated onto ALOA agar (agar for Listeria according to Ottaviani and Agosti).It was found that applied temperature and storage time significantly influenced the survival rate of listeriae (p<0.01). The number of L. monocytogenes in all the samples decreased linearly with storage time. The slowest decrease in the number of the bacteria was found in the samples stored at 6 o C (D-10 value = 243.9 h), whereas the highest reduction in the number of the bacteria was observed in the samples stored at 15 o C (D-10 value = 87.0 h). The number of L. monocytogenes was correlated with the pH value of the samples (p<0.01). The natural logarithm of the mean survival/inactivation rates of L. monocytogenes calculated from the primary model was fitted to two secondary models, namely linear and polynomial. Mathematical equations obtained from both secondary models can be applied as a tool for the prediction of the survival/inactivation rate of L. monocytogenes in yogurt stored under temperature range from 3 to 15 o C, however, the polynomial model gave a better fit to the experimental data.

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“…Inactivation of pathogenic bacteria in fermented milk products, including yogurt, was found by many authors (Rubin and Vaughan 1979, Rubin et al 1982, Alm 1983, Kotz et al 1990, Issa and Ryser 2000, Á lvarez-Ordóñ ez et al 2013, Cirone et al 2013. The main mechanism of bactericidal effect of yogurt on Salmonella and other pathogens seems to be the decline in pH due to lactose fermentation and the production of organic acids, mainly lactic acid, by Lactobacillus delbrueckii ssp.…”

Section: Discussionmentioning

confidence: 97%

“…However, these bacteria may survive in final product for some time dependent on the type of product, its pH, storage temperature and other environmental conditions. Cirone et al (2013) presented evidence that pathogenic bacteria like Mycobacterium avium subsp. paratuberculosis, E. coli, and S. Enteritidis could survive yogurt fermentation conditions and low pH levels followed by refrigerated storage for at least 20 days.…”

Section: Introductionmentioning

confidence: 99%

Modeling the effect of temperature on survival rate of Salmonella Enteritidis in yogurt

Szczawinski

Szczawinska

Łobacz³

et al. 2014

Polish Journal of Veterinary Sciences

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The aim of the study was to determine the inactivation rates of Salmonella Enteritidis in commercially produced yogurt and to generate primary and secondary mathematical models to predict the behaviour of these bacteria during storage at different temperatures. The samples were inoculated with the mixture of three S. Enteritidis strains and stored at 5 C for 24 h. The number of salmonellae was determined every two hours. It was found that the number of bacteria decreased linearly with storage time in all samples. Storage temperature and pH of yogurt significantly influenced survival rate of S. Enteritidis (p < 0.05). In samples kept at 5 o C the number of salmonellae decreased at the lowest rate, whereas at 25 o C the reduction in number of bacteria was the most dynamic. The natural logarithm of mean inactivation rates of Salmonella calculated from primary model was fitted to two secondary models: linear and polynomial. Equations obtained from both secondary models can be applied as a tool for prediction of inactivation rate of Salmonella in yogurt stored under temperature range from 5 to 25 o C; however, polynomial model gave the better fit to the experimental data.

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Growth ofMycobacterium aviumsubsp.paratuberculosis,Escherichia coli, andSalmonellaEnteritidis during Preparation and Storage of Yogurt

Cited by 11 publications

References 29 publications

Escherichia coli O157:H7 SURVIVAL IN TRADITIONAL AND LOW LACTOSE YOGURT DURING FERMENTATION AND COOLING PERIODS

Escherichia coli O157:H7 SURVIVAL IN TRADITIONAL AND LOW LACTOSE YOGURT DURING FERMENTATION AND COOLING PERIODS

Modeling the effect of temperature on survival rate of Listeria monocytogenes in yogurt

Modeling the effect of temperature on survival rate of Salmonella Enteritidis in yogurt

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