Kinetics of Bacillus coagulans spore inactivation in tomato juice by combined pressure–heat treatment

Food Control ◽  
2013 ◽  
Vol 30 (1) ◽  
pp. 168-175 ◽  
Author(s):  
Hossein Daryaei ◽  
V.M. Balasubramaniam
2012 ◽  
Vol 75 (7) ◽  
pp. 1236-1242 ◽  
Author(s):  
JING PENG ◽  
JAE-HYUNG MAH ◽  
ROMEL SOMAVAT ◽  
HUSSEIN MOHAMED ◽  
SUDHIR SASTRY ◽  
...  

The thermal characteristics of the spores and vegetative cells of three strains of Bacillus coagulans (ATCC 8038, ATCC 7050, and 185A) in tomato juice were evaluated. B. coagulans ATCC 8038 was chosen as the target microorganism for thermal processing of tomato products due to its spores having the highest thermal resistance among the three strains. The thermal inactivation kinetics of B. coagulans ATCC 8038 spores in tomato juice between 95 and 115°C were determined independently in two different laboratories using two different heating setups. The results obtained from both laboratories were in general agreement, with z-values (z-value is defined as the change in temperature required for a 10-fold reduction of the D-value, which is defined as the time required at a certain temperature for a 1-log reduction of the target microorganisms) of 8.3 and 8.7°C, respectively. The z-value of B. coagulans 185A spores in tomato juice (pH 4.3) was found to be 10.2°C. The influence of environmental factors, including cold storage time, pH, and preconditioning, upon the thermal resistance of these bacterial spores is discussed. The results obtained showed that a storage temperature of 4°C was appropriate for maintaining the viability and thermal resistance of B. coagulans ATCC 8038 spores. Acidifying the pH of tomato juice decreased the thermal resistance of these spores. A 1-h exposure at room temperature was considered optimal for preconditioning B. coagulans ATCC 8038 spores in tomato juice.


2009 ◽  
Vol 117 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Netsanet Shiferaw Terefe ◽  
Mala Gamage ◽  
Kamaljit Vilkhu ◽  
Lloyd Simons ◽  
Raymond Mawson ◽  
...  

2010 ◽  
Vol 638-642 ◽  
pp. 1743-1748
Author(s):  
G.J. Chen ◽  
Y.H. Shih ◽  
Jason S.C. Jang ◽  
S.R. Jian ◽  
P.H. Tsai ◽  
...  

In this study,the (FePt)94-xCu6Nbx (x=0, 2.87, 4.52, 5.67) alloy films were prepared by co-sputtering. The effects of Nb addition content and heat treatment on the microstructure and magnetic properties of the polycrystalline FePtCu films are reported. Our previous experiments showed that the ordering temperature of the (FePt)94Cu6 films reduced to 320 °C, which is much lower than that of the FePt alloy. However, the grain growth after heat treatment limited the practical application in recording media. By adding the Nb content in the (FePt)94Cu6 film, the grain sizes of the films can be adjusted from 50 to 18nm, even for the films annealed at temperature as high as 600°C. DSC traces of as-deposited disorder films at different heating rates, to evaluate the crystallization of the order phase, revealed that the addition of Nb enhanced the activation energy of ordering from 87 kJ/mol to 288 kJ/mol for the (FePt)94-xCu6Nbx (x=0 and 2.87, respectively) films. The reduction of the grain size and the corresponding increase in the activation energy of the Fe-Pt-Cu-Nb films might result from the precipitation of the Nb atoms around the ordering FePt phase. The (FePt)94-xCu6Nbx (x=2.87) film showed a coercive force of 13.4 kOe and the magnetization of 687 emu/cc.


Transfusion ◽  
2008 ◽  
Vol 48 (4) ◽  
pp. 790-790 ◽  
Author(s):  
Johannes Blümel ◽  
Albert Stühler ◽  
Herbert Dichtelmüller

2000 ◽  
Vol 63 (11) ◽  
pp. 1503-1510 ◽  
Author(s):  
ADRIENNE E. H. SHEARER ◽  
C. PATRICK DUNNE ◽  
ANTHONY SIKES ◽  
DALLAS G. HOOVER

Sucrose laurates, sucrose palmitate, sucrose stearates, and monolaurin (Lauricidin) were evaluated for inhibitory effects against spores of Bacillus sp., Clostridium sporogenes PA3679, and Alicyclobacillus sp. in a model agar system. The combined treatment of sucrose laurate, high hydrostatic pressure, and mild heat was evaluated on spores of Bacillus and Alicyclobacillus in foods. The minimum inhibitory concentrations of the sucrose esters were higher than that of Lauricidin for all spores tested in the model agar system, but Lauricidin was not the most readily suspended in the test media. The sucrose laurates and sucrose palmitate were more effective and more readily suspended than the sucrose stearates. A combined treatment of sucrose laurate (≤1.0%), 392 megaPascals (MPa) at 45°C for 10 to 15 min provided 3- to 5.5-log10 CFU/ml reductions from initial populations of 106 CFU/ml for Bacillus subtilis 168 in milk, Bacillus cereus 14579 in beef, Bacillus coagulans 7050 in tomato juice (pH 4.5), Alicyclobacillus sp. N1089 in tomato juice (pH 4.5), and Alicyclobacillus sp. N1098 in apple juice. The most notable change in the appearance of the products was temporary foaming during mixing of the sucrose laurate in the foods. The effect of sucrose laurate appeared to be inhibitory rather than lethal to the spores. The inhibitory effects observed on Bacillus and Alicyclobacillus spores by the combined treatment of pressure, mild heat, and sucrose laurate appear promising for food applications where alternatives to high heat processing are desired.


Refractories ◽  
1982 ◽  
Vol 23 (3-4) ◽  
pp. 203-206
Author(s):  
N. F. Fedorov ◽  
A. P. Gavrilov ◽  
N. I. Ivanov ◽  
N. M. Stepovaya

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