... Shear stressshear rate data were fitted to the Newtonian, Bingham, Herschel Bulkley, Power l... more ... Shear stressshear rate data were fitted to the Newtonian, Bingham, Herschel Bulkley, Power law and Casson Models. ... Shear stressshear rate data were fitted to the Newtonian, Bingham, Herschel Bulkley, Power law and Casson Models. ...
Ohmic heating is an alternative fast-heating method especially for liquid foods. In this study, p... more Ohmic heating is an alternative fast-heating method especially for liquid foods. In this study, pomegranate juice samples, prepared by two different extraction methods, were heated ohmically by matching the same thermal history, with that of the conventional method. The ohmic heating application was conducted by changing the voltage gradient (10—40 V/cm) at 50 Hz. The samples were heated from 20 ° C to 90°C and held at 90 °C for different treatment times (0, 3, 6, 9 or 12 min). Although rheological properties, color, and total phenolic content (TPC) values changed at the initial heating up period, there were no significant changes during holding period (p < 0.05). Non-Newtonian (power law) rheology model had higher regression coefficient than Newtonian model, and the extraction method affected the consistency of pomegranate juice samples (p < 0.05). Color values of juice extracted from arils (APJ) was better than that of juice extracted from whole fruits (PPJ), as PPJ containe...
Foodborne viruses, in particular human norovirus and hepatitis A virus, are the most common cause... more Foodborne viruses, in particular human norovirus and hepatitis A virus, are the most common causes of food-associated infections and foodborne illness outbreaks around the world. Since it is currently not possible to cultivate human noroviruses and the wild-type strain of hepatitis A virus in vitro, the use of a variety of viral surrogates is essential to determine appropriate thermal processing conditions to reduce the risk associated with their contamination of food. Therefore, the objectives of this review are to (i) present pertinent characteristics of enteric foodborne viruses and their viral surrogates, (ii) discuss the viral surrogates currently used in thermal inactivation studies and their significance and value, (iii) summarize available data on thermal inactivation kinetics of enteric viruses, (iv) discuss factors affecting the efficacy of thermal treatment, (v) discuss suggested mechanisms of thermal inactivation, and (vi) provide insights on foodborne enteric viruses an...
Human noroviruses (HNoV) and hepatitis A virus (HAV) have been implicated in outbreaks linked to ... more Human noroviruses (HNoV) and hepatitis A virus (HAV) have been implicated in outbreaks linked to the consumption of presliced ready-to-eat deli meats. The objectives of this research were to determine the thermal inactivation kinetics of HNoV surrogates (murine norovirus 1 [MNV-1] and feline calicivirus strain F9 [FCV-F9]) and HAV in turkey deli meat, compare first-order and Weibull models to describe the data, and calculate Arrhenius activation energy values for each model. The D (decimal reduction time) values in the temperature range of 50 to 72°C calculated from the first-order model were 0.1 ± 0.0 to 9.9 ± 3.9 min for FCV-F9, 0.2 ± 0.0 to 21.0 ± 0.8 min for MNV-1, and 1.0 ± 0.1 to 42.0 ± 5.6 min for HAV. Using the Weibull model, the t D = 1 (time to destroy 1 log) values for FCV-F9, MNV-1, and HAV at the same temperatures ranged from 0.1 ± 0.0 to 11.9 ± 5.1 min, from 0.3 ± 0.1 to 17.8 ± 1.8 min, and from 0.6 ± 0.3 to 25.9 ± 3.7 min, respectively. The z (thermal resistance) valu...
Cilekte bozunma sonucu meydana gelen fizikokimyasal ve biyolojik reaksiyonlar doku, renk, aroma, ... more Cilekte bozunma sonucu meydana gelen fizikokimyasal ve biyolojik reaksiyonlar doku, renk, aroma, tat ve vitamin kaybina neden olmaktadir. Bu nedenle cileklerin raf omrunu arttirmak icin cesitli on islemler uygulanmaktadir. Bu calismada; cilek orneklerine uygulanan ultrason (32 kHz’de 20; 50 ve 65 oC) ve UV-C (12.36 W/m2) uygulamalarinin, cilek kalitesi uzerine etkileri arastirilmistir. Uygulanan islemlerin mikrobiyal acidan etkinligini saptamak icin ise toplam mezofil mikroorganizmalarin sayimina bakilmistir. UV-C uygulamasinin renk, doku, pH, antosiyanin miktari gibi kalite ozelliklerinin korunmasi acisindan en etkili alternatif yontem oldugu, ancak bu teknigin mikrobiyal acidan yeterli inaktivasyon saglayamadigi belirlenmistir. Isi uygulanarak yapilan ultrason isleminin ise mikrobiyal etkinlige sahip olmasina ragmen renkte bozulma ve dokuda yumusamaya neden oldugu gozlenmistir. Isitma ve ultrasonun birlikte kullanildigi islemin ozellikle 65 °C’de, mikrobiyal inaktivasyon uzerine isil etkisinin yani sira ultrasonik etkisinin de oldugu saptanmistir. Alternatif bir teknolojinin ticari kullanima adapte edilebilmesi icin temel amac hem yuksek derecede guvenilirlige sahip olmasi hem de duyusal ve besin icerigi acisindan daha az degisime neden olmasidir. Alternatif metotlarin kombinasyonlari endustriyel olcekte en uygun teknigin uygulanmasina olanak saglayabilir.
International journal of food microbiology, Jan 16, 2015
Leafy vegetables have been recognized as important vehicles for the transmission of foodborne vir... more Leafy vegetables have been recognized as important vehicles for the transmission of foodborne viral pathogens. To control hepatitis A viral foodborne illness outbreaks associated with mildly heated (e.g., blanched) leafy vegetables such as spinach, generation of adequate thermal processes is important both for consumers and the food industry. Therefore, the objectives of this study were to determine the thermal inactivation behavior of hepatitis A virus (HAV) in spinach, and provide insights on HAV inactivation in spinach for future studies and industrial applications. The D-values calculated from the first-order model (50-72°C) ranged from 34.40±4.08 to 0.91±0.12min with a z-value of 13.92±0.87°C. The calculated activation energy value was 162±11kJ/mol. Using the information generated in the present study and the thermal parameters of industrial blanching conditions for spinach as a basis (100°C for 120-180s), the blanching of spinach in water at 100°C for 120-180s under atmospheri...
Leafy greens, including spinach, have potential for human norovirus transmission through improper... more Leafy greens, including spinach, have potential for human norovirus transmission through improper handling and/or contact with contaminated water. Inactivation of norovirus prior to consumption is essential to protect public health. Because of the inability to propagate human noroviruses in vitro, murine norovirus (MNV-1) and feline calicivirus (FCV-F9) have been used as surrogates to model human norovirus behavior under laboratory conditions. The objectives of this study were to determine thermal inactivation kinetics of MNV-1 and FCV-F9 in spinach, compare first-order and Weibull models, and measure the uncertainty associated with the process. D-values were determined for viruses at 50, 56, 60, 65, and 72°C in 2-ml vials. The D-values calculated from the first-order model (50 to 72°C) ranged from 0.16 to 14.57 min for MNV-1 and 0.15 to 17.39 min for FCV-9. Using the Weibull model, the tD for MNV-1 and FCV-F9 to destroy 1 log (D = 1) at the same temperatures ranged from 0.22 to 15....
... Shear stressshear rate data were fitted to the Newtonian, Bingham, Herschel Bulkley, Power l... more ... Shear stressshear rate data were fitted to the Newtonian, Bingham, Herschel Bulkley, Power law and Casson Models. ... Shear stressshear rate data were fitted to the Newtonian, Bingham, Herschel Bulkley, Power law and Casson Models. ...
Ohmic heating is an alternative fast-heating method especially for liquid foods. In this study, p... more Ohmic heating is an alternative fast-heating method especially for liquid foods. In this study, pomegranate juice samples, prepared by two different extraction methods, were heated ohmically by matching the same thermal history, with that of the conventional method. The ohmic heating application was conducted by changing the voltage gradient (10—40 V/cm) at 50 Hz. The samples were heated from 20 ° C to 90°C and held at 90 °C for different treatment times (0, 3, 6, 9 or 12 min). Although rheological properties, color, and total phenolic content (TPC) values changed at the initial heating up period, there were no significant changes during holding period (p < 0.05). Non-Newtonian (power law) rheology model had higher regression coefficient than Newtonian model, and the extraction method affected the consistency of pomegranate juice samples (p < 0.05). Color values of juice extracted from arils (APJ) was better than that of juice extracted from whole fruits (PPJ), as PPJ containe...
Foodborne viruses, in particular human norovirus and hepatitis A virus, are the most common cause... more Foodborne viruses, in particular human norovirus and hepatitis A virus, are the most common causes of food-associated infections and foodborne illness outbreaks around the world. Since it is currently not possible to cultivate human noroviruses and the wild-type strain of hepatitis A virus in vitro, the use of a variety of viral surrogates is essential to determine appropriate thermal processing conditions to reduce the risk associated with their contamination of food. Therefore, the objectives of this review are to (i) present pertinent characteristics of enteric foodborne viruses and their viral surrogates, (ii) discuss the viral surrogates currently used in thermal inactivation studies and their significance and value, (iii) summarize available data on thermal inactivation kinetics of enteric viruses, (iv) discuss factors affecting the efficacy of thermal treatment, (v) discuss suggested mechanisms of thermal inactivation, and (vi) provide insights on foodborne enteric viruses an...
Human noroviruses (HNoV) and hepatitis A virus (HAV) have been implicated in outbreaks linked to ... more Human noroviruses (HNoV) and hepatitis A virus (HAV) have been implicated in outbreaks linked to the consumption of presliced ready-to-eat deli meats. The objectives of this research were to determine the thermal inactivation kinetics of HNoV surrogates (murine norovirus 1 [MNV-1] and feline calicivirus strain F9 [FCV-F9]) and HAV in turkey deli meat, compare first-order and Weibull models to describe the data, and calculate Arrhenius activation energy values for each model. The D (decimal reduction time) values in the temperature range of 50 to 72°C calculated from the first-order model were 0.1 ± 0.0 to 9.9 ± 3.9 min for FCV-F9, 0.2 ± 0.0 to 21.0 ± 0.8 min for MNV-1, and 1.0 ± 0.1 to 42.0 ± 5.6 min for HAV. Using the Weibull model, the t D = 1 (time to destroy 1 log) values for FCV-F9, MNV-1, and HAV at the same temperatures ranged from 0.1 ± 0.0 to 11.9 ± 5.1 min, from 0.3 ± 0.1 to 17.8 ± 1.8 min, and from 0.6 ± 0.3 to 25.9 ± 3.7 min, respectively. The z (thermal resistance) valu...
Cilekte bozunma sonucu meydana gelen fizikokimyasal ve biyolojik reaksiyonlar doku, renk, aroma, ... more Cilekte bozunma sonucu meydana gelen fizikokimyasal ve biyolojik reaksiyonlar doku, renk, aroma, tat ve vitamin kaybina neden olmaktadir. Bu nedenle cileklerin raf omrunu arttirmak icin cesitli on islemler uygulanmaktadir. Bu calismada; cilek orneklerine uygulanan ultrason (32 kHz’de 20; 50 ve 65 oC) ve UV-C (12.36 W/m2) uygulamalarinin, cilek kalitesi uzerine etkileri arastirilmistir. Uygulanan islemlerin mikrobiyal acidan etkinligini saptamak icin ise toplam mezofil mikroorganizmalarin sayimina bakilmistir. UV-C uygulamasinin renk, doku, pH, antosiyanin miktari gibi kalite ozelliklerinin korunmasi acisindan en etkili alternatif yontem oldugu, ancak bu teknigin mikrobiyal acidan yeterli inaktivasyon saglayamadigi belirlenmistir. Isi uygulanarak yapilan ultrason isleminin ise mikrobiyal etkinlige sahip olmasina ragmen renkte bozulma ve dokuda yumusamaya neden oldugu gozlenmistir. Isitma ve ultrasonun birlikte kullanildigi islemin ozellikle 65 °C’de, mikrobiyal inaktivasyon uzerine isil etkisinin yani sira ultrasonik etkisinin de oldugu saptanmistir. Alternatif bir teknolojinin ticari kullanima adapte edilebilmesi icin temel amac hem yuksek derecede guvenilirlige sahip olmasi hem de duyusal ve besin icerigi acisindan daha az degisime neden olmasidir. Alternatif metotlarin kombinasyonlari endustriyel olcekte en uygun teknigin uygulanmasina olanak saglayabilir.
International journal of food microbiology, Jan 16, 2015
Leafy vegetables have been recognized as important vehicles for the transmission of foodborne vir... more Leafy vegetables have been recognized as important vehicles for the transmission of foodborne viral pathogens. To control hepatitis A viral foodborne illness outbreaks associated with mildly heated (e.g., blanched) leafy vegetables such as spinach, generation of adequate thermal processes is important both for consumers and the food industry. Therefore, the objectives of this study were to determine the thermal inactivation behavior of hepatitis A virus (HAV) in spinach, and provide insights on HAV inactivation in spinach for future studies and industrial applications. The D-values calculated from the first-order model (50-72°C) ranged from 34.40±4.08 to 0.91±0.12min with a z-value of 13.92±0.87°C. The calculated activation energy value was 162±11kJ/mol. Using the information generated in the present study and the thermal parameters of industrial blanching conditions for spinach as a basis (100°C for 120-180s), the blanching of spinach in water at 100°C for 120-180s under atmospheri...
Leafy greens, including spinach, have potential for human norovirus transmission through improper... more Leafy greens, including spinach, have potential for human norovirus transmission through improper handling and/or contact with contaminated water. Inactivation of norovirus prior to consumption is essential to protect public health. Because of the inability to propagate human noroviruses in vitro, murine norovirus (MNV-1) and feline calicivirus (FCV-F9) have been used as surrogates to model human norovirus behavior under laboratory conditions. The objectives of this study were to determine thermal inactivation kinetics of MNV-1 and FCV-F9 in spinach, compare first-order and Weibull models, and measure the uncertainty associated with the process. D-values were determined for viruses at 50, 56, 60, 65, and 72°C in 2-ml vials. The D-values calculated from the first-order model (50 to 72°C) ranged from 0.16 to 14.57 min for MNV-1 and 0.15 to 17.39 min for FCV-9. Using the Weibull model, the tD for MNV-1 and FCV-F9 to destroy 1 log (D = 1) at the same temperatures ranged from 0.22 to 15....
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