Gonzalo Zurera Cosano

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• Catedrático
• Profesor, Investigador at University of Córdoba

Listeria monocytogenes is the foodborne pathogen responsible for listeriosis in humans. Its ability to grow at refrigeration temperatures, particularly in products that support its growth and have a long-refrigerated shelf-life, poses a significant health risk, especially for vulnerable consumer groups such as pregnant woman and immunocompromised i...

Understanding the role of food-related factors on the efficacy of protective cultures is essential to attain optimal results for developing biopreservation-based strategies. The aim of this work was to assess and model growth of Latilactobacillus sakei CTC494 and Listeria monocytogenes CTC1034, and their interaction, in two different ready-to-eat f...

In this study, the bioprotective potential of Lactobacillus sakei CTC494 against Listeria monocytogenes CTC1034 was evaluated on vacuum packaged hot-smoked sea bream at 5 °C and dynamic temperatures ranging from 3 to 12 °C. The capacity of three microbial competition interaction models to describe the inhibitory effect of L. sakei CTC494 on L. mono...

The occurrence of various foodborne disease outbreaks linked to the consumption of cucumbers worldwide in the last years raised concerns regarding the survival ability of foodborne pathogens on this food matrix. This work aimed at evaluating and quantifying the survival of Escherichia coli O157:H7 and Salmonella spp. on cucumber surfaces. Cucumbers...

This study was aimed at characterizing microbiologically Gilthead sea bream (Sparus aurata) and Sea bass (Dicentrarchus labrax) produced in two estuarine ecosystems in Andalusia (Spain): the estuary of the river Guadalquivir (La Puebla del Río, Sevilla) (A), and the estuary of the river Guadiana (Ayamonte, Huelva) (B). The collected fish individual...

In this study, the inhibitory capacity of Lactobacillus sakei strain L115 against Listeria monocytogenes has been assayed at 4, 8, 11, 15 and 20 °C in broth culture. Besides, the use of predictive microbiology models for describing growth of both microorganisms in monoculture and coculture has been proposed. A preliminary inhibitory test confirmed...

The objective of this work was to quantitatively evaluate the effect of Lactobacillus sakei CTC494 (sakacin-producing bioprotective strain) against Listeria monocytogenes in fish juice and to apply and validate three microbial interaction models (Jameson, modified Jameson and Lotka Volterra models) through challenge tests with gilthead sea bream (S...

A tool able to quantitatively assess the fate of potential pathogenic microorganisms in foods along the food chain and their impact on public health is highly valuable for food safety decision-makers. The aim of this work was to present an overview of the Predictive Microbiology software MicroHibro, which is able to assess the evolution of potentia...

Over the last couple of decades, several studies have evaluated growth dynamics of L. monocytogenes in lightly processed and ready-to-eat (RTE) fishery products mostly consumed in Nordic European countries. Other fish species from aquaculture production are of special interest since their relevant consumption patterns and added value in Mediterrane...

Traditionally, fish processors have regarded quality assurance as the responsibility of the regulatory governmental agency, and the means used by these agencies have been the formulation of food laws and regulations, inspection of facilities, and processes and final product testing. Microbiological hazards in foodstuffs form a major source of foodb...

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Content: The aim of this work was to investigate and model the behavior of Listeria monocytogenes in vegetable infusions and emulsions of these infusions and olive oil. To this end, vegetables infusion based on tomato, artichoke, eggplant and oyster mushroom was generated in water and pH was adjusted to 4.5 in order to simulate conditions in canned...

Content: The aim of this work was to investigate and model the behavior of Listeria monocytogenes in vegetable infusions and emulsions of these infusions and olive oil. To this end, vegetables infusion based on tomato, artichoke, eggplant and oyster mushroom was generated in water and pH was adjusted to 4.5 in order to simulate conditions in canned...

Aims: The objective of this work was to study the growth potential of E. coli O157:H7 and Salmonella spp. in leafy vegetable extracts at different temperature conditions. Methods and results: Cocktails of five strains of E. coli O157: H7 and of S. enterica were used. Inoculated aqueous vegetable extracts were incubated at 8, 10, 16 and 20°C duri...

The authors regret to inform that there is a small error in equations of Bias factor (Bf) and Accuracy factor (Af). Terms gobs and gpred are in the incorrect order (although calculations are right). Bf = 10[∑log(gpred/gobs) / n] Af = 10[∑│log(gpred/gobs)│/ n] The authors would like to apologise for any inconvenience caused.

Microbial survival on inert surfaces should be considered as an important factor to understand and quantify bacterial transfer to foods (i.e. cross contamination). The present work studied the survival of Escherichia coli O157:H7 and Salmonella spp. on stainless steel surfaces with different soiling substrates based on leafy vegetable juices. Furth...

The survival of Escherichia coli O157:H7 and Staphylococcus aureus on stainless steel surfaces with Saline Solution (SS), Tryptone Soy Broth (TSB) and meat purge was studied, and based on results, mathematical models describing survival of pathogens as a function of time were proposed. Results indicated that S. aureus was able to survive longer tha...

This study was conducted in eight Spanish school canteens during the period 2008-2009. Food handlers' practices, kitchen equipment, hygiene/sanitation conditions and handling practices were evaluated using checklists. In parallel, the microbiological quality and safety of ready-to-eat (RTE) vegetable salads were assessed. In addition, food contact...

Ready-to-eat lettuce is a food commodity prone to contamination by pathogenic microorganisms if processing and distribution conditions as well as handling practices are not effective. A challenge testing protocol was applied to ready-to-eat iceberg-lettuce samples by inoculating different initial contamination levels (4.5, 3.5 and 2.5 log cfu/g) of...

Food industry is increasingly concerned in developing and applying rapid and nondestructive methods to offer safer and high quality foods to consumers. During the last years, Fourier transform near-infrared (FT-NIR) has been widely used to determine food quality based on spectrum. Likewise, FT-NIR has been proposed as an innovative and promising no...

Food safety measures in long-term care facilities (LTCFs) are being improved by the introduction of quality control management systems during food production and by the implementation of good manufacturing practices. This study was conducted in LTCFs (geriatric homes) in Andalusia, Spain, during 2008 and 2009 to evaluate sanitary conditions and the...

Chilled Ready-To-Eat (RTE) foods are of concern in hospital foodservices because they can support microbial growth when subjecting to time/temperature abuses during processing and distribution together with poor handling practices. This study was conducted in five different hospitals (A–E) of Southern Spain during 2008–2009 to perform an evaluation...

A stochastic simulation modelling approach was taken to determine the extent of Escherichia coli O157:H7 contamination in fresh-cut bagged lettuce leaving the processing plant. A probabilistic model was constructed in Excel to account for E. coli O157:H7 cross contamination when contaminated lettuce enters the processing line. Simulation of the mod...

Cooked meat ready-to-eat products are recognized to be contaminated during slicing which, in the last years, has been associated with several outbreaks. This work aimed to find out possible relation between the hygiene practice taking place at retail point during slicing of cooked meat products in small and medium-sized establishments (SMEs) and la...

The presence of Escherichia coli in contaminated food products is commonly attributed to faecal contamination when they are improperly handled and/or when inactivation treatments fail. Adaptation of E. coli at low pH and a(w) levels can vary at different temperatures depending on the serotype, thus more detailed studies are needed. In this work, a...

Foodborne diseases constitute a major concern in societies, and their causes are aimed to be identified and minimized. Only in the last few years, this is encouraged by the application of risk assessment, management, and communication. This work presents a probabilistic quantitative microbiological risk assessment and management of Listeria monocyt...

Boundary models have been recognized as useful tools to predict the ability of microorganisms to grow at limiting conditions. However, at these conditions, microbial behaviour can vary, being difficult to distinguish between growth or no growth. In this paper, the data from the study of Valero et al. [Valero, A., Pérez-Rodríguez, F., Carrasco, E.,...

The seasonal changes in concentrations of calcium (Ca), magnesium (Mg), sodium (Na) and potassium (K) present in the milk of the three main milk-producing species (cow, ewe and goat) were studied for 1 year by using flame atomic absorption spectrophotometry. The mean concentrations obtained for the four minerals studied, Ca, Mg, Na and K, were: 1.2...

The seasonal changes in concentrations of copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn) present in the milk of the three main milk-producing species (cow, ewe and goat) were studied for one year by using flame atomic absorption spectrophotometry. The mean concentrations obtained for the four minerals studied, Cu, Fe, Zn and Mn, were: 0.16 ±...

The microbial behaviour of five enterotoxigenic strains of Staphylococcus aureus was studied in the growth/no growth domain. A polynomial logistic regression equation was fitted using a stepwise method to study the interaction of temperature (8, 10, 13, 16 and 19 degrees C), pH (4.5; 5.0; 5.5; 6.0; 6.5 7.0 and 7.5) and water activity (A(w)) (19 lev...

Listeria monocytogenes, when present, could be able to grow on Ready-to-Eat (RTE) iceberg lettuce. This investigation demonstrates that L. monocytogenes grows on packaged shredded iceberg lettuce held at 13 or 5 °C (maximum growth rate of 0.019 and 0.013 log cfu/h, respectively), with increments of 4.85 and 2.66 log cfu/g, respectively, after 14 da...

Bacterial transfer events are considered to be an important cause of transmission of food-borne diseases. In this review the most common ways of bacterial transfer to food are studied, concluding that high levels of moisture, contact time and pressure could result in higher transfer between surfaces. From a risk management approach, this means that...

A recent Draft regulation adopted by the Commission of the European Communities establishes microbiological criteria in foods. For the pathogen Listeria monocytogenes in a specific food category, two different microbiological criteria are proposed, and the application of either depends on the demonstration that L. monocytogenes will not exceed a ce...

Increasing demand for fresh-cut or ready-to-eat fruits and vegetables, developed to meet the consumer need for quick and convenient products, has prompted extensive research into their microbiological quality, safety, processing, and packaging. The microbial ecology of Listeria monocytogenes is recognized as a major safety concern for fresh-cut pro...

Staphylococcus aureus contamination of foods is one of the most prevalent causes of gastroenteritis worldwide, which is caused by ingestion of preformed toxins. Ready-to-eat foods without previous heat treatment before consumption are susceptible to be contaminated during processing, storage or handling at both retail points and domestic homes. In...

A new approach to predict the growth/no growth interface of Listeria monocytogenes as a function of storage temperature, pH, citric acid (CA) and ascorbic acid (AA) is presented. A linear logistic regression procedure was performed and a non-linear model was obtained by adding new variables by means of a Neural Network model based on Product Units...

Cross contamination is one of the most important contributing factors in foodborne illnesses originating in household environments. The objective of this research was to determine the transfer coefficients between a contaminated domestic slicing machine and a cooked meat product, during slicing. The microorganisms tested were Staphylococcus aureus...

The risk assessment study of Listeria monocytogenes in ready-to-eat foods conducted by the U.S. Food and Drug Administration is an example of an extensive quantitative microbiological risk assessment that could be used by risk analysts and other scientists to obtain information and by managers and stakeholders to make decisions on food safety manag...

The lead and cadmium content of 89 samples of some edible mushrooms, corresponding to 8 different species, were determined by atomic absorption spectrophotometry to evaluate the importance of mushrooms as a dietary source of both elements. Lead content of the selected mushrooms ranged from less than 0.058 to 1.85 mg/kg, whereas cadmium content vari...

The effects of storage temperature and time on the microflora of fresh, vacuum packaged, and modified atmospheres packaged asparagus (Asparagus officinalis) were analyzed. Total aerobic mesophilic, psychrophilic, lactic acid bacteria, Enterobacteriaceae, and yeast and molds were determined as a function of time. The effect of washing on the origina...

Abstract The shelf-life of vacuum packed, sliced, cooked chicken-breast based on sensory and microbial changes as a function of temperature (2.3, 6.5, 10, 13.5 and 17.7C) was determined. Sensory evaluation and a microbiological study charted the development of lactic acid and psychotropic bacteria and of Brochothrix thermosphacta. Six different sen...

Growth of Listeria monocytogenes in pasteurized white asparagus was monitored at different storage temperatures (4, 10, 20, and 30 degrees C). Among the main microbial kinetic parameters, growth rate (mu) per hour was calculated at each temperature using the Baranyi-Roberts model. L. monocytogenes was able to grow at all temperatures, although at 4...

The recent Commission Regulation (EC) No 2073/2005 establishes microbiological criteria in foods. For the pathogen Listeria monocytogenes in the category ready-to-eat foods able to support its growth, other than those intended for infants and for special medical purposes, two different microbiological criteria are proposed: (i) L. monocytogenes lev...

The impact of precultural temperature and pH on the distribution of the lag phase of individual Listeria monocytogenes cells was assessed during preincubation at 7 degrees C, using a dilution protocol to obtain single cells, and optical density measurements to estimate the individual lag phase. Firstly, the pure temperature effect (37, 15, 10, 7, 4...

Different secondary modeling approaches for the estimation of Listeria monocytogenes growth rate as a function of temperature (4 to 30 degrees C), citric acid (0% to 0.4% w/v), and ascorbic acid (0% to 0.4% w/v) are presented. Response surface (RS) and square-root (SR) models are proposed together with different artificial neural networks (ANN) bas...

A linear logistic regression model was built to describe the growth/no growth boundaries of Listeria monocytogenes as a function of temperature (4–30°C), pH (4.5–6), citric acid (0–0.4%) and ascorbic acid (0–0.4%). A fractional factorial design was followed among the factors considered and an inoculum size of 105CFU/ml was used. Evaluation of growt...

A practical approach was used to achieve specified food safety objectives (FSOs) by incorporating risk assessment methodology. A series of cross-contamination scenarios at the retail level were evaluated in a spreadsheet and ranked according to their level of risk, and the degree to which they exceeded an FSO for Listeria monocytogenes (100 CFU/g)...

  The influence of environmental conditions (temperature and pH) on the relationship between growth data expressed by absorbance (ABS) and data transformed to cell count (CC) measurements was studied, using calibration curves for predicting Listeria monocytogenes growth rate. With this aim, 19 calibration curves at different stress conditions were...

Changes in the mineral content of peas (Pisum sativum, L.) as a function of size during commerical processing were studied. Peas were divided into four levels of maturity, and samples were taken on different sizes of peas at various stages of the canning process. Mineral content was determined by atomic absorption spectrophotometry. significant cha...

This study simulates the conditions in which Botrytis may appear in a modified atmosphere packed horticulture product, such as strawberry, so as to elaborate a predictive model that could allow us to estimate the shelf-life of a contaminated food product in such atmosphere conditions (0 to 40% CO2). The estimated shelf-lives obtained at 18 °C were...

The combined effects of different temperatures (10.5–24.5 °C), pH level (5.5–7.5), sodium chloride levels (0.25–6.25%) and sodium nitrite levels (0–200 ppm) on the predicted growth rate and lag-time of Leuconostoc mesenteroides under aerobic and anaerobic conditions was studied. The response surface (RS) model developed provided reliable estimates...

Changes in sensory quality and proliferation of pathogenic and spoilage microorganisms in pasteurized white asparagus were measured as a function of storage temperature. The main sensorial attributes studied with regard to storage time were the general appearance of the product, turgidity and package swelling. There was a significant correlation be...

This article presents a new approach to the Artificial Neural Networks (ANN) modeling of bacterial growth; using Neural Network models based on Product Units (PUNN) instead of on sigmoidal units (multilayer perceptron type [MLP]) of kinetic parameters (lag-time, growth rate, and maximum population density) of Leuconostoc mesenteroides and those fac...

This article presents a new approach to the Artificial Neural Networks (ANN) modeling of bacterial growth; using Neural Network models based on Product Units (PUNN) instead of on sigmoidal units (multilayer perceptron type [MLP]) of kinetic parameters (lag-time, growth rate, and maximum population density) of Leuconostoc mesenteroides and those fac...

A response surface model of Listeria monocytogenes’ growth rate was built in this study under different temperatures (10 °C, 15 °C, 20 °C, 25 °C and 30 °C) and acid concentrations: citric acid (0–0.4%) and ascorbic acid (0–0.4%); two ingredients which are often used in the food industry as preservatives. Mathematical validation was performed with a...

The combined effect of temperature (10.5 to 24.5 degrees C), pH level (5.5 to 7.5), sodium chloride level (0.25% to 6.25%) and sodium nitrite level (0 to 200 ppm) on the predicted specific growth rate (Gr), lag-time (Lag) and maximum population density (yEnd) of Leuconostoc mesenteroides under aerobic and anaerobic conditions, was studied using an...

An Artificial Neural Network-based predictive model (ANN) for Leuconostoc mesenteroides growth in response to temperature, pH, sodium chloride and sodium nitrite, developed by Garcia-Gimeno et al. [Int. J. Food Microbiol. (2005)]) was validated on vacuum packed, sliced, cooked meat products and applied to shelf-life determination. Lag-time (Lag), g...

In this study, we assessed the impact of pre-cultural temperature and pH on the lag phase of individual Listeria monocytogenes cells at 7°C. In a first step, the pre-cultural temperature effect (37, 15, 10, 7, 4 and 2°C) was investigated on a subsequent growth at 7°C and pH 7.4. In a second step, low pre-cultural temperatures (10, 7 and 4°C) were c...

In this study, a Response Surface Model (RSM) of Escherichia coli O157:H7 as affected by pH levels, sodium chloride and nitrite concentrations, temperature, and aerobic/anaerobic conditions is presented. The standard error of prediction (%SEP) obtained was acceptable for the growth rate prediction (33%SEP), although a bit high for lag time (53.01 %...

It is well known that the factors most affecting the growth of microorganisms are pH, storage temperature, water activity, preservatives, and modification of atmosphere during packaging (Gibson et al., 1988), among others. Given an adequate database, the response of many microbes in food can be predicted based on knowledge of the food’s formulation,...

The contents of macroelements (Ca, Mg, Na, K y P) and trace elements (Cu, Fe, Zn and Mn) of frozen green asparagus were determined by atomic absorption spectrometry to investigate the possible changes during 45 and 90 days frozen storage at –18C. A significant decrease of mineral concentrations was observed at 45 days of frozen storage. After 90 da...

The combined effect of different temperatures (7 to 19 degrees C), pH levels (4.5 to 8.5), sodium chloride levels (0 to 8%), and sodium nitrite levels (0 to 200 ppm) on the predicted growth rate and lag time of Staphylococcus aureus under aerobic and anaerobic conditions was studied. The two predictive models developed, response surface (RS) and th...

The combined effect of different temperatures (7 to 19degreesC), pH levels (4.5 to 8.5), sodium chloride levels (0 to 8%), and sodium nitrite levels (0 to 200 ppm) on the predicted growth rate and lag time of Staphylococcus aureus under aerobic and anaerobic conditions was studied. The two predictive models developed, response surface (RS) and the...

Artificial neural networks (ANN) was evaluated and compared with Response Surface Model (RSM) results using growth response data for E.coli O157:H7 as affected by 5 variables: pH, sodium chloride, and nitrite concentrations, temperature, and aerobic/anaerobic conditions. The best ANN obtained, where the 2 kinetic parameters, growth rate and lag-tim...

The growth of Staphylococcus aureus in commercially available vacuum-packaged cooked ham, turkey breast meat, and chicken breast meat stored at 2.3, 6.5, 10, 13.5, and 17.7 degrees C was studied. Growth rates observed in these food products were compared with those predicted on the basis of various growth models found in the literature and with tho...

Lead content was investigated in infant formulas by using graphite furnace atomic absorption spectroscopy (GFAAS). Formulas were distinguished as 'beginner', 'continuation' and 'special infant formula', the latter being classified as subtypes 'hypoallergenic', 'without lactose', 'vegetable base' and 'others'. The mean concentrations of lead were 25...

An alternative method based on artificial neural networks (ANN) for the estimation of kinetic growth parameters of a microorganism is performed by applying an automatic regression on different sections of the growth curve so as to obtain more precise growth rate and lag-time values. Through the combination of genetic algorithms and pruning methods...

Cadmium content was investigated in infant formulas by using graphite furnace atomic absorption spectroscopy (GFAAS). Formulas were distinguished as "beginner", "continuation" and "special infant formulas", the last ones were classified as subtypes "hypoallergenic", "without lactose", "vegetable base" and "others". The mean concentrations of cadmiu...

The power of computational neural networks (CNN) for microbiological growth prediction was evaluated. The training set consisted of growth responses data from a combination of three strains of Salmonella in a laboratory medium as affected by pH level, sodium chloride concentration and storage temperature. The architecture of CNN was designed to con...

Growth of Listeria monocytogenes in packaged fresh green asparagus was investigated at different temperatures The present study monitored the growth of L. monocytogenes in packaged fresh green asparagus stored at 2, 4, 8, 12 and 20 degrees C. Changes in carbon dioxide, oxygen concentrations and pH were determined. Growth data were fitted to the Bar...

An evaluation was made of the degree of toughening of asparagus during its storage through a study of the morphological and cellular differences of the xylem vascular bundles as a function of the variety, thickness and portion of the asparagus spear. Light microscopic examinations were carried out to determine the thickness of the cell wall to quan...

Lead and cadmium were determined in fresh and canned asparagus, at each step of the canning process, by atomic absorption spectrophotometry to evaluate the contribution of these vegetables to the daily intake of cadmium and lead in Spain. Lead content of the asparagus ranged from less than 0.074 mg/kg to 0.292 mg/kg, whereas cadmium content varied...

Changes in the essential trace elements (copper, iron, manganese and zinc) of the asparagus (Asparagus officinalis, L.) were determined in order to investigate the effect of the industrial processing of asparagus on mineral content and estimate if these possible changes involve a modification of its nutritional value. The main effect was a decrease...

Changes in the copper, iron, zinc, manganese, nickel, chromium, calcium, magnesium, sodium, potassium and phosphorus content of fresh green asparagus (Asparagus officinalis L) according to the portion of spear considered and differences existing between varieties (Mary-Washington and UC-150) and thicknesses (<11 and 14mm) asparagus were investigate...

Variations in lead and cadmium contents were deter mined throughout the: pasteurizing, sterilizing and desiccation (to obtain powdered milk) processes by graphite furnace atomic absorption spectrophotometry. No statistically significant differences were observed (p>0.05) from an analysis of variance (ANOVA) which was performed to compare lead and c...

Nine essential elements (copper, iron, zinc, manganese, calcium, magnesium, sodium potassium and phosphorous) were determined in white asparagus (Asparagus officinalis, L.) by flame atomic absorption spectrophotometry in order to examine the possible variations in mineral content caused by frozen storage at −18C for 45 and 90 days. Statistically si...

Changes in concentrations of nickel present in cow's, ewe's and goat's milk were studied monthly (n = 360 samples) by using graphite furnace atomic absorption spectrometry. The mean concentrations of nickel are 15.0 ± 3.81, 18.6± 2.50 and 13.6 ± 2.46 μg·kg-1 of fresh weight for cow's, ewe's and goat's milk respectively. Two-factor (species and time...

Variations in the copper, iron, zinc, manganese, calcium, magnesium, sodium, potassium and phosphorous content of fresh white asparagus (Asparagus officinalis, L.) as a function of the spear portion and the differences between varieties (Desto and Cipré's) and thicknesses (< 11 and > 14 mm) of asparagus were investigated. The mineral elements studi...

An objective method to predict shelf-life and spoilage of packaged green asparagus would be desirable. The present study monitored the evolution of spoilage organisms in packaged fresh green asparagus stored at 2, 4, 8, 12 and 20°C. Changes in carbon dioxide, oxygen concentrations and pH were recorded. Predictive modelling was used to establish a t...

Variations in nickel content were determined by graphite furnace atomic absorption spectrophotometry throughout the process of making and ripening Manchego-type cheese. The products from cheesemaking process showed statistically significant differences (p<0.01) for the nickel levels, and Tukey's homogeneity test (p<0.05) revealed 2 homogeneous grou...

Concentrations of calcium, magnesium, sodium, potassium and phosphorus were determined in white asparagus (Asparagus officinalis, L.) by atomic absorption spectrophotometry to investigate and estimate if the influence of industrial processing on mineral content and mineral nutritional value of different varieties, diameters and portions of white as...

Variations in cadmium content were determined throughout cheese manufacturing and ripening processes by applying graphite furnace atomic absorption spectrophotometry to samples of natural pasteurized milk, rennet, curd whey, pressed curd, pressing whey and cheese. The total mean cadmium contents were 4.79 +/- 2.4 and 4.67 +/- 2.1 microgram/kg fresh...

The influence of certain industrial processing operations of white asparagus (Asparagus officinalis, L.) on concentrations of chromium and nickel was studied. Samples of white asparagus were taken during the following operations of the industrial processing: reception and selection of raw material (fresh asparagus), after machine-washing (washed as...

Batches of white asparagus (Asparagus officinalis, L. var Ciprés) were analyzed by flame atomic absorption spectrophotometry to investigate the variations in chromium and nickel contents caused by the freezing process and storage of spears at −18C for 45 and 90 days. Samples of asparagus were classified into two groups according to diameter, < 11 m...

The shelf-life of ready-to-eat vegetable salads established by manufacturers is usually 7-14 days depending on the type of vegetable, and is determined by loss in organoleptic qualities. A more objective method to predict shelf-life and spoilage would be desirable. The present study monitored the evolution of spoilage organisms in a mixed salad of...

The modifications in the chromium (Cr) and nickel (Ni) content and the distribution of these trace elements in white asparagus spears (Asparagus officinalis, L.) were investigated. Samples were taken of two varieties of white asparagus, Desto and Ciprés, and grouped in function of their thickness in spears of < 11 mm and of > 14 mm. All the asparag...

The aim of this study was to evaluate the survival and potential growth ofAeromonas hydrophilain commercial mixed vegetable salads composed of lettuce, red cabbage and carrots, packed under modified atmosphere and stored at 4 and 15°C. The evolution of carbon dioxide, oxygen and pH values was determined. A sensory panel assessed changes to organole...

ABSTRACTA total of 116 commercial samples of mixed vegetable salads, packaged in plastic bags, were examined for the presence of Listeria monocytogenes during storage at 4C. Commercial products, belonging to 4 different batches, were sampled over a period of one year and stored for 300 h at 4C in the laboratory. Different sets of enrichment and pla...

The essential elements: calcium (Ca), magnesium (Mg), sodium (Na) potassium (K) and phosphorus (P) were analyzed in fresh asparagus to determine the effect of the ripening of the asparagus on the mineral content. Asparagus samples were classified in two groups by diameter (14 mm). Asparagus from a sample group with the same diameter were divided in...

Variations in mineral content were determined throughout the process of making cheese, taking samples of natural, pasteurised milk, with additions of rennet, curd, whey, pressed curd, pressing whey and cheese. The mean contents in cheese were 7·59mg/g for calcium, 0·309mg/g for magnesium, 6·46mg/g for sodium. 1·38mg/g for potassium and 0·364μg/g fo...