Santiago Condon

Santiago Condon
University of Zaragoza | UNIZAR · Faculty of Veterinary

Catedrático de Universidad

About

174
Publications
32,482
Reads
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8,153
Citations
Additional affiliations
January 1990 - December 1990
Universidad de León
Position
  • PostDoc Position
Description
  • Research on heat resistance of Aeromonas hydrophila
January 1985 - present
University of Zaragoza
Position
  • Full Professor of Food Technology
Description
  • Microbial inactivation by heat, high electric field pulses, high pressure, ultrasound, ultraviolet light.

Publications

Publications (174)
Article
Although antimicrobials are valuable allies in animal production, their extended use has led to unexpected threats associated with the emergence and propagation of antimicrobial resistance. Moreover, when withdrawal periods in food-producing animals are not observed, antimicrobial residues can access the food chain, causing direct toxicity, allergi...
Chapter
The present chapter provides a wide overview of the possibilities currently offered by the technology of pulsed electric fields (PEF) within the framework of microbial inactivation. The modes of action of PEF on microbial cells are discussed, along with potential cell outcomes after the application of PEF. The most adequate current methods for the...
Article
Deviations in linearity in survival curves are common in inactivation kinetics during heat treatment. These might lead one to underestimate how effective thermal treatment is. In previous research we reported a relationship between decimal reduction time values (DT) and shoulder lengths (Sl) of survival curves which was characteristic of each micro...
Article
Full-text available
Even though antibiotics are necessary in livestock production, they can be harmful not only due to their toxicity, but also in view of their contribution to the emergence of antimicrobial resistance. Screening tests based on microbial growth inhibition appeared to be useful tools to prevent its entry into the food chain. They have nevertheless been...
Article
Full-text available
Many of the infectious diseases that affect livestock have bacteria as etiological agents. Thus, therapy is based on antimicrobials that leave the animal’s tissues mainly via urine, reaching the environment through slurry and waste water. Once there, antimicrobial residues may lead to antibacterial resistance as well as toxicity for plants, animals...
Article
To date, heat is still the most used technology in food preservation. The calculus of heat treatments is usually based on Bigelow observations i.e. treatment time is an exponential function of the heat treatment temperature. However, a number of researchers have reported deviations from linearity in heat inactivation curves that caused errors in th...
Article
Full-text available
The introduction of antimicrobial residues in the food chain has a significant impact on human health. An innovative solution to avoid their presence in meat is the adaptation of current control methods for use with in vivo matrixes. Thus, the aim was to obtain paired blood and muscle samples from pigs treated with some of the main antimicrobials c...
Article
The combination of UV-C radiation and mild heat (UV-H) treatment is a promising strategy for synergistically increasing microbial inactivation in low UV-transmitting juices. In this research, we explored the suitability of UV-H treatment in carrot juice pasteurization and its impact on juice quality during shelf-life compared to that of thermal pas...
Article
Traditional and novel technologies for food preservation are being investigated to obtain safer products and fulfil consumer demands for less processed foods. These technologies inactivate microorganisms present in foods through their action on different cellular targets, but the final cause of cell loss of viability often remains not well characte...
Article
Heat treatments are widely used by the food industry to obtain safe and stable products, therefore a deeper knowledge of its mode of action on microorganisms would allow a better profit of this technology. Heat shows a multitarget mechanism of action on bacteria, affecting various cellular structures, and causing unbalances in several homeostatic p...
Article
In this work the influence of growth temperature (10-42 °C) on Staphylococcus aureus heat resistance was studied, and its relationship with the ability of cells to repair sublethal damages and with membrane fluidity was evaluated. Non-linear, convex from above survival curves were obtained, and therefore a special case of the Baranyi model was used...
Article
Ultrasonic treatments are one of the new technologies for microbial inactivation that could serve as an alternative for food preservation. However, decimal reduction times for most of microbial species generally exceed 1 min. Therefore, combined processes have been designed, based on the simultaneous application of ultrasonic waves under pressure a...
Article
The consumption of crustaceans is correlated with certain health risks, particularly due to several highly toxic elements they contain, including cadmium (Cd). Although Cd content in one sole crab generally exceeds the total weekly recommended intake of cadmium as established by EFSA (especially in brown meat), efficient modern strategies to reduce...
Article
The present work was performed to evaluate the potential of electron beam ionizing radiation for the inactivation of three psychrophilic spore forming bacteria (Bacillus mycoides, Bacillus weihenstephanensis and Psychrobacillus psychrodurans) isolated from ready-to-eat brown crab (Cancer pagurus). Inactivation curves for the three spores were perfo...
Article
Full-text available
Heat has been used extensively in the food industry as a preservation method, especially due to its ability to inactivate microorganisms present in foods. However, many aspects regarding the mechanisms of bacterial inactivation by heat and the factors affecting this process are still not fully understood. The purpose of this review is to offer a ge...
Chapter
Social changes in recent decades have led to new standards in food, which in turn have given rise to a set of new problems. At present, food poisoning is not only a public health issue of great importance, but the phenomenon tends to be on the rise, even in developed countries. In addition, market globalization and the cheapening of transport requi...
Article
The combination of ultraviolet radiation and heat (UV-H treatment) has been demonstrated as a promising strategy to overcome the limited UV germicidal effect in fruit juices. Nonetheless, there are so far no data regarding the efficacy of the combined process for the inactivation of bacterial foodborne pathogens in other liquid foods with different...
Article
Heat treatments are widely used by the food industry to inactivate microorganisms, however their mode of action on microbial cells is not fully known. In the last years, it has been proposed that the generation of oxidative species could be an important factor contributing to cell death by heat and by other stresses; however, investigations in this...
Article
The influence of growth and treatment temperature (10–42 °C) on Staphylococcus aureus resistance to Pulsed Electric Fields (PEF) was investigated. No statistical differences in resistance to PEF (26 kV/cm) (p > 0.05) were detected between S. aureus cells grown at 10, 20, 37, or 42 °C. In contrast, suspensions grown at 30 °C displayed significantly...
Article
Full-text available
In this paper the resistance of bacterial foodborne pathogens to manosonication (MS), pulsed electric fields (PEF), high hydrostatic pressure (HHP) and UV-light (UV) is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtai...
Article
This research evaluates the potential use of ultraviolet C light (UV-C) as a decontamination method for powdered foods, particularly of refined flour. This technology's lethal effectiveness was evaluated on Salmonella enterica subsp. Enterica serotype Typhimurium and Lactobacillus plantarum in wheat flour, and in laboratory liquid media of differen...
Article
This research was performed to characterize the resistance of three different bacterial spores species isolated form pasteurized edible crab (Cancer pagurus) meat to heat treatments and to assess the potential of manosonication (MS) and manothermosonication (MTS) as an alternative for their inactivation. The spore-forming bacteria used in this stud...
Chapter
Traditionally, ultraviolet (UV) light has been used for decontaminating air, surfaces and water supplies. In the last decade, the potential to implement UV light as an alternative food processing method to heat treatment has caught the attention of the food industry, which wishes to fulfill consumers’ demands for minimally processed food products....
Article
Full-text available
This investigation established the process criteria for using UV-C light and mild heat (UV-H treatment) to inactivate 5-Log 10 cycles (performance criterion) of common foodborne pathogen populations, Escherichia coli , Salmonella Typhimurium, Listeria monocytogenes , and Staphylococcus aureus , when inoculated in chicken broth. To define the target...
Article
The UV–C resistance of yeasts (Saccharomyces cerevisiae, Saccharomyces bayanus, Zygosaccharomyces bailii, Dekkera anomala and Dekkera bruxellensis) commonly involved in juice spoilage was investigated. Saccharomyces spp. showed the greatest UV resistance and yeast inactivation decreased with absorptivity of the medium. To improve the UV lethal effe...
Article
The suitability of NaCl-added selective media for the quantification of electroporated bacterial cells was evaluated using Staphylococcus aureus as a model microorganism. A very good correspondence was found between the percentage of cells unable to outgrow in media added with the Maximum Non Inhibitory Concentration of NaCl and the percentage of e...
Article
The aim of this work was to examine the role of the alternative general stress sigma factors σ(B) and rpoS on the ability of Staphylococcus aureus and Escherichia coli, respectively, to grow in liquid and solid media of different osmolarity. For this purpose, S. aureus strain Newman and its isogenic ΔsigB mutant IK84 and E. coli strain BJ4 and its...
Article
Full-text available
Commercial apple juice inoculated with Escherichia coli was treated with UV-C, heat (55°C) and dimethyl dicarbonate - DMDC (25, 50, and 75 mg/L)-, applied separately and in combination, in order to investigate the possibility of synergistic lethal effects. The inactivation levels resulting from each treatment applied individually for a maximum trea...
Article
Full-text available
The aim of this paper was to assess the incidence of antimicrobial residues in market muscle samples from different animal species (bovine, ovine, poultry and porcine) using a new screening strategy. 4849 samples were evaluated with a methodology that combines a broad spectrum microbial test (Explorer) and a specific test for quinolones detection...
Article
In this investigation, the effect of microbiological factors (strain, growth phase, exposition to sublethal stresses, and photorepair ability), treatment medium characteristics (pH, water activity, and absorption coefficient), and processing parameters (dose and temperature) on the UV resistance of Listeria monocytogenes was studied. The dose to in...
Article
Cell suspensions of Listeria monocytogenes 5366, Staphylococcus aureus 976 and Pseudomonas aeruginosa 110T were exposed to high pressure treatment from 200 to 600 MPa for 5, 10 and 15 min at an initial temperature of 20 °C in raw skimmed bovine milk, whey and phosphate buffer, pH 7.0 in order to determine their degree of inactivation. S. aureus was...
Article
In this investigation, temperature's effect on the ultraviolet (UV) inactivation kinetics of pathogens of concern in juices – E. coli, Salmonella Typhimurium, L. monocytogenes, and S. aureus – was studied to establish the target microorganism and process criteria for pasteurizing apple juice using combined shortwave UV-C light and mild heat (UV-H)...
Article
Pulsed ultraviolet (PUV) light involves the use of high-peak-power pulsed light of short duration and a broad spectrum ranging from ultraviolet to infrared wavelengths. This technology has been reported to have the potential to inactivate a broad range of spoilage and pathogenic microorganisms by limiting the negative effects on product quality and...
Article
Ultraviolet (UV)-C treatments are a promising technology for liquid food pasteurization as an alternative to heat treatments. However, the design of efficient UV reactors to reduce pertinent microorganisms and comply with current food safety goals is still an engineering challenge due to the low penetration depth of UV light in liquid foods with hi...
Article
The NaCl MNICs (maximum non-inhibitory concentrations) and MICs (minimum inhibitory concentrations) for growth of various strains of six bacterial species were determined and then compared with those obtained for seven other solutes. The influence of prior growth conditions on the MNICs and MICs was also evaluated. No significant changes on the MNI...
Article
Full-text available
The thermal inactivation of Enterococcus faecium under isothermal conditions in tryptic soy broth of different pH (4.0, 5.5 and 7.4) was studied. The bacterial cells were more sensitive at higher temperature and in media of low pH. Decimal reduction times at 71ºC were 2.56, 0.39 and 0.03 min at pH 7.4, 5.5 and 4.0 respectively. At all temperatures...
Chapter
Irreversible electroporation of microbial membranes caused by pulsed electric fields (PEFs) is an effective way to inactivate vegetative cells of microorganisms. Based on this effect, PEF provides an alternative to conventional thermal pasteurization of heat-sensitive foods. The objective of this chapter is to provide a comprehensive overview of th...
Article
Full-text available
Processing unit operations that seek to inactivate harmful microorganisms are of primary importance in ascertaining the safety of food. The capability of pulsed electric fields (PEF) to inactivate vegetative cells of microorganisms at temperatures below those used in thermal processing makes this technology very attractive as a nonthermal pasteuriz...
Article
This study investigates the effects of different concentrations (50–200 ppm) of (+)-limonene or orange essential oil (EO) when designing thermal treatments to pasteurize orange juice (OJ) at different temperatures (54–60 °C). The addition of 200 ppm of (+)-limonene or orange EO to commercial OJ reduced the heating time to inactivate 5 log10 cycles...
Article
The effect of bactericidal UV-C treatments (254 nm) on Escherichia coli O157:H7 suspended in apple juice increased synergistically with temperature up to a threshold value. The optimum UV-C treatment temperature was 55°C, yielding a 58.9% synergistic lethal effect. Under these treatment conditions, the UV-heat (UV-H55°C) lethal variability achievin...
Article
The potential to commercialize nonthermal ultraviolet (UV) light technologies as new methods for preserving food products has caught the attention of a food industry that wishes to fulfill consumers' demands for fresh products. Numerous investigations have demonstrated UV light's ability to inactivate a wide range of microorganisms. However, the la...
Article
In this investigation, the resistance of enterotoxigenic Staphylococcus aureus to short-wave ultraviolet light (UV-C) and to combined UV C-heat (UV-H) treatments in buffers and in liquid foods with different physicochemical characteristics was studied. Microbial resistance to UV-C varied slightly among the S. aureus strains tested. The UV-C resista...
Article
The bactericidal efficacy of ultraviolet (UV) treatments to fruit juices is limited because of their low UV transmittance; therefore, it is necessary to design combined processes to improve their lethality. This investigation was carried out to determinate the lethal effect of UV-C treatments at mild temperatures (UV-H treatments) on the UV-resista...
Article
In this investigation we selected and isolated a culture derived from Salmonella enterica serovar Typhimurium SL1344 with stable increased resistance to pulsed electric fields (PEF) after repeated rounds of PEF treatment and outgrowth of survivors. The resulting culture showed a higher resistance to PEF treatments under different treatment conditio...
Article
This investigation evaluates the ability of UV light to inactivate bacterial spores of interest for food preservation. It also evaluates the effect of the absorptivity of the treatment medium on UV lethality and the effect of the simultaneous or sequential combination of UV light and mild heating. A UV dose of 23.72 J/mL reached 2.25, 2.93, 3.24, 3...
Article
Full-text available
The inactivation of Listeria monocytogenes and Escherichia coli suspended in apple and orange juices by ultrasound under pressure at nonlethal (manosonication, MS) and lethal temperatures (manothermosonication, MTS) was evaluated. Significant differences were found in the MS resistance (35 °C, 110 μm, 200 kPa) of three strains of L. monocytogenes a...
Article
Full-text available
UV light only penetrates liquid food surfaces to a very short depth, thereby limiting its industrial application in food pasteurization. One promising alternative is the combination of UV light with mild heat (UV-H), which has been demonstrated to produce a synergistic bactericidal effect. The aim of this article is to elucidate the mechanism of sy...
Article
Full-text available
Survival rates of Escherichia coli and Staphylococcus aureus after high-pressure treatment in buffers that had large or small reaction volumes (ΔV°), and which therefore underwent large or small changes in pH under pressure, were compared. At a low buffer concentration of 0.005 M, survival was, as expected, better in MOPS (morpholinepropanesulfonic...
Article
It is difficult to guarantee the effectiveness of UV technology to reach 5 Log10 cycles of inactivation of Escherichia coli in a large amount of fruit juices with high absorption coefficients and turbidities, such as orange juice. The aim of this work was to overcome this limitation by combining UV light and mild temperatures. UV treatments were ca...
Article
Full-text available
The aim of this investigation was to study the efficacy of the combined processes of UV light and mild temperatures for the inactivation of Salmonella enterica subsp. enterica and to explore the mechanism of inactivation. The doses to inactivate the 99.99% (4D) of the initial population ranged from 18.03 (Salmonella enterica serovar Typhimurium STC...
Article
This paper evaluates the physicochemical and functional properties of liquid whole egg (LWE) processed by alternative treatments based on the application of Pulsed Electric Fields (25 kV/cm, 75 kJ/kg) followed by heat (52 °C/3.5 min, 55 °C/2 min or 60 °C/1 min) in the presence of 2% triethyl citrate (LWE-TC-PEF-HT), and by current heat pasteurizati...
Article
Abstract The purpose of this research was to study the effect of different factors on the resistance of Cronobacter sakazakii NCTC 9238 to UV-C light (which includes germicidal ultraviolet light at 254 nm) and to determine whether a combined treatment with heat would produce a synergistic effect for its inactivation. Growth temperature between 10°C...
Article
This paper evaluates the possibilities of combined processes based on the successive application of pulsed electric fields (PEF) and heat, in the presence of additives (EDTA and triethyl citrate (TC)), as an alternative to liquid whole egg (LWE) industrial ultrapasteurization. Firstly, the lethality of the combined processes on two heat-resistant m...
Article
This work approaches the possibility of combining mild heat treatments with citrus fruit essential oils (EOs) to improve the effectiveness of heat treatments and thus to reduce treatment intensity. Concentrations between 10 and 200μL/L of lemon, mandarin, or orange EO were tested at 54°C for 10min in laboratory media, determining that 200μL/L of ea...
Article
This paper evaluates the lethal effectiveness on 7 different Salmonella serovars of the application, in static and continuous conditions, of pulsed electric fields (PEF) followed by heat treatments in liquid whole egg (LWE) with additives (EDTA or triethyl citrate-TC-). Compared to heat treatments, the PEF (25 kV/cm and 75-100 kJ/kg) followed by he...
Article
Staphylococcus aureus cells were exposed to acid (4.5) and alkaline (9.5) pH, hydrogen peroxide (50 μM), sodium chloride (10%), heat (45°C) and to a cold shock (4°C) for two hours and then treated by pulsed electric fields (PEF). Exposing S. aureus cells to acidic, oxidative, hyperosmotic or cold-shock conditions resulted in no protection to PEF. B...
Article
The combined effect of the simultaneous application of heat and ultrasonic waves under pressure (manothermosonication, MTS) on the survival of a strain of Cronobacter sakazakii was studied in apple juice. Below 45 °C, the inactivation by ultrasound under pressure was independent of temperature. Above 64 °C, the lethal effect of ultrasound under pre...
Article
The objective was to study the response of Cronobacter sakazakii ATCC 29544 cells to heat, pulsed electric fields (PEF), ultrasound under pressure (Manosonication, MS) and ultraviolet light (UV-C) treatments after exposure to different sublethal stresses that may be encountered in food-processing environments. Cronobacter sakazakii stationary growt...
Article
The aim of this investigation is to evaluate the concurrent influence of temperature (4–50°C), pH (3.5–7.0), and the presence of nisin (up to 200μg/mL) on the inactivation of two PEF-resistant Gram-negative, pathogenic bacteria, Salmonella Typhimurium STCC 878 and Escherichia coli O157:H7, using a PEF treatment of 30kV/cm and 99μs. A response surfa...
Article
This investigation aimed to determine the role of general stress-response alternative sigma factors σS (RpoS) and σB (SigB) in heat resistance and the occurrence of sublethal injuries in cell envelopes of stationary-phase Escherichia coli BJ4 and Listeria monocytogenes EGD-e cells, respectively, as a function of treatment medium pH. Given that micr...
Article
The influence of treatment parameters (dose and temperature), treatment medium characteristics (absorption coefficient, pH and water activity) and microbiological factors (strain, growth phase and UV damage and repair capacity) on Escherichia coli UV-C resistance has been investigated. UV-C doses to inactivate at 25°C 99.99% of the initial populati...
Article
The inactivation of Cronobacter sakazakii by heat and ultrasound treatments under pressure at different temperatures [manosonication (MS) and manothermosonication (MTS)] was studied in citrate-phosphate pH 7.0 buffer and rehydrated powdered milk. The inactivation rate was an exponential function of the treatment time for MS/MTS treatments (35-68 °C...
Article
The effect of High Hydrostatic Pressure (HHP) on the survival of Cronobacter sakazakii was investigated. Deviations from linearity were found on the survival curves and the Mafart equation accurately described the kinetics of inactivation. Comparisons between strains and treatments were made based on the time needed for a 5-log(10) reduction in via...
Article
This paper is an evaluation of the lethal effectiveness of a successive application of pulsed electric fields (PEFs) and heat treatment in liquid whole egg (LWE) in the presence of different additives on the population of Salmonella serovar Enteritidis. Synergistic reductions of the Salmonella Enteritidis population were observed when LWE samples c...
Article
Full-text available
Concerns regarding the presence of drug residues in foods include allergic reactions, toxicity, technological problems in fermented products and the development of antibiotic resistance in human pathogens. The analysis of antimicrobial residues in foods is generally carried out, in a first step, through microbiological screening tests. These tests...
Article
The objective of this research was to characterize the resistance of Cronobacter sakazakii to ultrasonic waves under pressure (manosonication, MS). The D(MS) value (decimal reduction time value) of C. sakazakii in standard conditions (35°C, 117 μm, 200 kPa, citrate-phosphate buffer pH 7.0) was 0.41 min. This value was higher than that of Yersinia e...