M.C. Pina-Pérez

Synergistic effect of pulsed electric fields and CocoanOX 12% on the inactivation kinetics of Bacillus cereus in a mixed beverage of liquid whole egg and skim milk.

With a view to extending the shelf-life and enhancing the safety of liquid whole egg/skim milk (LWE-SM) mixed beverages, a study was conducted with Bacillus cereus vegetative cells inoculated in skim milk (SM) and LWE-SM beverages, with or without antimicrobial cocoa powder. The beverages were treated with Pulsed Electric Field (PEF) technology and then stored at 5 degrees C for 15 days. The kinetic results were modeled with the Bigelow model, Weibull distribution function, modified Gompertz equation, and Log-logistic models. Maximum inactivation registered a reduction of around 3 log cycles at 40 kV/cm, 360 micros, 20 degrees C in both the SM and LWE-SM beverages. By contrast, in the beverages supplemented with the aforementioned antimicrobial compound, higher inactivation levels were obtained under the same treatment conditions, reaching a 3.30 log(10) cycle reduction. The model affording the best fit for all four beverages was the four-parameter Log-logistic model. After 15 days of storage, the antimicrobial compound lowered Bacillus cereus survival rates in the samples supplemented with CocoanOX 12% by a 4 log cycle reduction, as compared to the untreated samples without CocoanOX 12%. This could indicate that the PEF-antimicrobial combination has a synergistic effect on the bacterial cells under study, increasing their sensitivity to subsequent refrigerated storage.

Inactivation kinetics of spores of Bacillus cereus strains treated by a peracetic acid-based disinfectant at different concentrations and temperatures.

The purpose of this study was to assess the effect of a commercial peracetic acid-based disinfectant against spores of Bacillus cereus, to identify the most influential factor for the final number of microorganisms after different disinfection procedures, and to evaluate the nature of the inactivation kinetics. The spores of four different strains of B. cereus (DSM 318, 4312, 4313, and 4384) were treated with five different disinfectant concentrations (0.25%, 0.5%, 1.0%, 1.5%, and 2.0% [w/v]) at three different temperatures (10°C, 15°C, and 20°C) with or without protein load. A higher temperature and PES 15/23 concentration resulted in a higher inactivation. Inactivation of B. cereus strain 4312 was around 2 log₁₀ cycles at 10°C and around 7 log₁₀ at 20°C (conc=1% [w/v] PAA; t=60 min; without protein). The protein load at higher concentrations did not significantly reduce the efficacy of the disinfectant (p>0.05). This article indicates the applicability of the Weibull model to fit the B. cereus disinfectant survival curves. A Monte Carlo simulation was used to carry out a sensitivity analysis, which revealed the most influential factors affecting the final number of microorganisms after the disinfection process.

Monte Carlo simulation as a method to determine the critical factors affecting two strains of Escherichia coli inactivation kinetics by high hydrostatic pressure.

The survival curves of two strains of Escherichia coli (ATCC 4157 and ATCC 23716) were obtained by high hydrostatic pressure (HHP) at four pressure levels (100, 200, 300, and 400 MPa) in an orange juice-skim milk (OJ-SM) mixed beverage. The effect of suspension medium pH on HHP inactivation was studied at three pH levels: 4, 4.5, and 5. The Weibull model provided an accurate fit to the data according to adjusted-regression coefficients (adjusted-R(2)) [0.860-0.996], root mean square error values [0.001-0.150], and accuracy factor [1.001-1.125] values. For sensitivity analysis, Monte Carlo simulation was run to determine the most influential factors affecting HHP inactivation of E. coli strains. According to these results, the most influential factor for E. coli (ATCC 4157) HHP inactivation was the pH of the OJ-SM beverage at low HHP intensity, whereas pressure was more influential under strong HHP treatment conditions. Concerning E. coli K-12 (ATCC 23716), pressure (P) was the most influential parameter independently of the pH of OJ-SM beverage. The higher the P, the higher the inactivation achieved. The sensitivity analysis indicated greater E. coli K-12 (ATCC 23716) resistance to the HHP processing, possibly because of greater acidity tolerance.

Nonthermal Inactivation of Cronobacter sakazakii in Infant Formula Milk: A Review

Up-to-date, nonthermal technologies and combinations of them, in accordance with the “hurdle technology” concept, are being applied by different research groups in response to calls by the International Food and Human Health Organizations (ESPGHAN, 2004; FAO/WHO, 2006, 2008) for alternatives to thermal control of Cronobacter sakazakii in reconstituted powdered infant formula milk. This review highlights (i) current knowledge on the application of nonthermal technologies to control C. sakazakii in infant formula milk and (ii) the importance of the application of nonthermal technologies for the control of C. sakazakii as part of the development of strategies in the context of improving food safety and quality of this product.

Bacteriostatic effect of cocoa powder rich in polyphenols to control Cronobacter sakazakii proliferation on infant milk formula

Public health authorities, researchers and manufacturers are urged to develop alternative preservatives methods for milk and dairy derivative products (infant milk formula, dairy beverages, etc) specifically to avoid or reduce foodborne illness among children [1]. Taking into account that epidemiological studies have implicated C. sakazakii as an occasional contaminant of powder infant products, specifically infant formulas, with severe consequences, it could be relevant to propose alternative control measures to avoid growth and infection by this microorganism. The possible inhibitory/bacteriostatic effect of cocoa powder to control Cronobacter sakazakii in milk formulas (MF) was studied at three concentrations: 1%, 2.5% and 5 % (w/v). The growth study was carried out at 25oC in MF and supplemented MF at different concentrations using an initial C. sakazakii concentration of 10 2 cfu/mL. The data results were fitted to Gompertz equation in order to obtain growth biological parameters. According to present study results, there are no significant differences between supplemented/not supplemented milk formula specific growth rate values (μ, h), which means that there is not an inhibitory effect of cocoa on C. sakazakii growth at 25oC. Related to lag phase values (λ, h) it was observed an extension of λ duration when MF was supplemented with cocoa at 5% (w/v). The results of the present study point out that a bacteriostatic but not inhibitory effect, on C. sakazakii cells, could be attributed to cocoa powder at 5% (w/v) concentration when it is added to milk formula and remains in contact with cells at ambient temperature (25oC). These results would be applied to a future pasteurized milk formula product supplemented with cocoa powder rich in polyphenols enhancing its shelf life.

Using natural antimicrobials to enhance the safety and quality of fruit- and vegetable-based beverages

This chapter reviews current advances related to the addition of natural antimicrobials to fruit-based beverages. It discusses the most important developments in enhancing beverage safety and quality, and examines, in detail, the biological basis of the contribution of the phytochemicals studied, individually or combined with other food-processing technologies.

Antimicrobial Potential of Flavoring Ingredients Against Bacillus cereus in a Milk-Based Beverage

Natural ingredients--cinnamon, cocoa, vanilla, and anise--were assessed based on Bacillus cereus vegetative cell growth inhibition in a mixed liquid whole egg and skim milk beverage (LWE-SM), under different conditions: ingredient concentration (1, 2.5, and 5% [wt/vol]) and incubation temperature (5, 10, and 22 °C). According to the results obtained, ingredients significantly (p<0.05) reduced bacterial growth when supplementing the LWE-SM beverage. B. cereus behavior was mathematically described for each substrate by means of a modified Gompertz equation. Kinetic parameters, lag time, and maximum specific growth rate were obtained. Cinnamon was the most bacteriostatic ingredient and cocoa the most bactericidal one when they were added at 5% (wt/vol) and beverages were incubated at 5 °C. The bactericidal effect of cocoa 5% (wt/vol) reduced final B. cereus log10 counts (log Nf, log10 (colony-forming units/mL)) by 4.10 ± 0.21 log10 cycles at 5 °C.

New Advances in Infant Feeding: New Products and Novel Technologies

BACKGROUND Breastfeeding is the best way to provide ideal food for infants. However, there are many situations in which breastfeeding is unviable (maternal illness, hygiene problems, intravenous feeding requirement, storage). Safe, efficient, and nutritious products should be offered by the industry to mothers and healthcare professionals as an alternative. OBJECTIVE The present review aims to update the state of the art regarding the most innovative developments in infant feeding formulation and, the promising novel technologies that are being investigated to achieve a balance between the microbiological stability, organoleptic and nutritional value of baby food. METHODS The research lines included in the present systematic review are focused on both, the most innovative ingredients and emergent technologies applied increasing the offer of tailor-made nutritional profiled products with improved quality and safety. RESULTS According to the reviewed research and recently published patents the current emergence of a new generation of infant products is remarkable, with specific product lines aimed at infants at different stages of development and affected by several disorders (low-weight babies, premature neonates, allergenic patients), with special emphasis on the application of novel technologies (e.g. High Hydrostatic Pressure (HHP) and microencapsulation) as potential techniques to ensure the microbiological safety of developed products, and the improvement of their nutritional value, complementary to the addition of functional ingredients, such as omega 3 and 6 fatty acids, amino acids, prebiotics and probiotics, and medicinal herb supplementation (e.g. lemon balm, royal jelly). CONCLUSION The present research work provides a general view of recent advances in infant products processing and formulation focusing on the technological effects and quality/safety developments.

Antimicrobial Capacity of a Cauliflower By-Product Infusion Combined with the PEF Treatment against S. Typhimurium

Salmonella spp is a foodborne pathogen related with food outbreaks worldwide. To control it, new strategies have been developed to preserve food products, such as the application of non-thermal treatments like pulsed electric fields (PEF) or the addition of antimicrobial compounds from vegetable by-products. The main objective of this study is to evaluate the antimicrobial effect of PEF treatment, combined with several concentrations of cauliflower by-product infusion against S. Typhimurium.

Using natural antimicrobials to enhance the safety and quality of alcoholic and other beverages

This chapter reviews current advances related to the addition of natural antimicrobials to various alcoholic and hot drinks, emphasizing the most important achievements in enhancing beverage safety and quality, and discussing in detail the biological basis of the contribution of the phytochemicals studied, individually or combined with other food-processing technologies.