MODELING THE GROWTH LIMIT OF ALICYCLOBACILLUS ACIDOTERRESTRIS CRA7152 IN APPLE JUICE: EFFECT OF PH, BRIX, TEMPERATURE AND NISIN CONCENTRATION

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The logistic regression model was used to describe the temperature effect (25 to 50C), pH(3.5 to 5.5), soluble solids concentration (11 to 19) and nisin concentration (0 to 70 IU/mL) on the growth probability of Alicyclobacillus acidoterrestris CRA 7152 in apple juice. The model concordance was 97.3%, indicating a good fit of the observed data. The results showed that with pH 3.7 the growth probabilities were small (<10(-5)) for nisin concentrations above 50 IU/mL. At 0.05 growth probability, minimum values of pH were established between 3.8 and 4.6 to inhibit the growth with the nisin synergistic action in concentration of 0 and 20 IU/mL, respectively, when the juice is incubated at 30C. The logistic model obtained can provide data to be used in quality control and at processes development. PRACTICAL APPLICATIONS This work applied predictive microbiology to develop a logistic model that can be used to reduce the recontamination of apple juice. The model obtained can be immediately used to food quality control, quality management, risk assessment and management, hazard analysis by control critical point, good manufacturing practices and cost reducing by allowing the prediction. The results also show that nisin plays an important role in the control of apple juice contamination by Alicyclobacillus acidoterrestris and it can be used in combination with pH, soluble solids concentration and temperature.354509517Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Desorption isotherms for murici (Byrsonima sericea) and inga (Inga edulis) pulps

Murici (Byrsonima sericea) and inga (Inga edulis) desorption isotherms were determined by the gravimetric method at two different temperatures. Experimental data was adjusted to five sorption models of Langmuir, Oswin, Anderson, GAB and Peleg. Sorption isotherms were determined gravimetrically by exposing the samples to controlled atmospheres produced by saturated salt solutions. The coefficient of regression R-2 and mean squares of error (E%) between experimental and calculated data were obtained to select the best model. In relation to the isotherm model the best models were, GAB and Oswin obtaining minor values of % mean errors and higher coefficient of determination. The GAB model was found to be the best fit out of the five models evaluated. (c) 2005 Elsevier Ltd. All rights reserved.76461161

Modelling Bacillus cereus adhesion on stainless steel surface as affected by temperature, pH and time

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The adhesion of Bacillus cereus to stainless steel was modelled as a function of pH (4.0-8.0), time (2-24 h) and temperature (4.0-36.0 degrees C) using response surface methodology. Based on the initial inoculum (3 or 6 log cfu mL(-1)), two equations describing B. cereus adhesion to stainless steel were obtained. The results indicated that B. cereus was able to reach up to 5.5 cfu cm(-2) and 6.4 cfu cm(-2) when the initial inocula were 3 log cfu mL(-1) and 6 log cfu mL(-1), respectively. The significance of the factors varied with the model; i.e., inoculum of 3 or 6 log cfu mL(-1). Bias and accuracy factors showed that the models are adequate to predict B. cereus adhesion to stainless steel surface under conditions assessed and to assess the adhesion of B. cereus under a range of conditions to which this microorganism can be exposed during either milk processing or cleaning procedures. (C) 2013 Elsevier Ltd. All rights reserved.341153158Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq