Transforming a public university hospital and its area of influence into a comprehensive resource in response to the COVID-19 pandemic.

INTRODUCTION AND OBJECTIVES: The outbreak of COVID-19 has overwhelmed healthcare systems all over the world. The aim of this article is to describe the process of transforming the Vall d'Hebron University Hospital, the second largest hospital in Spain, into a COVID-19 centre coordinating response to the pandemic in its reference area. MATERIALS AND METHODS: The study draws on the experience of the authors in transforming the hospital into a comprehensive resource in response to the COVID-19 pandemic. The strategy is based on four central strategies: early planning, coordination of all healthcare agents in its reference area, definition of clear leadership roles, and the organisation of care based on multidisciplinary teams with minimal recruitment of new staff. RESULTS: The transformation strategy enabled the hospital to cope with the surge in patients without exceeding its capacity. During the response phases, which amounted to a period of 57 days, 3106 patients consulted the ER and 2054 were admitted, 346 of whom were treated at the ICU. To accommodate the number of adult COVID-19 patients, adult ICU availability was progressive increased by 371%, and ordinary beds increased by 240. A total of 671 staff members went on sick leave after testing positive for COVID-19. CONCLUSION: The transformation experience of the hospital provides insight into how effectively adapt the structures and functioning of large hospitals. The relevance of territorial coordination during the pandemic is stressed as an effective strategy that contributed coping the pandemic.

Pathogenic potential of the surviving Salmonella Enteritidis on strawberries after disinfection treatments based on ultraviolet-C light and peracetic acid.

Fresh fruits, especially strawberries, are usually consumed raw without any step to ensure their food safety. Salmonella enterica is one of the most important etiologic agents for foodborne diseases throughout the world and its ability to respond to some stress responses makes it even more dangerous. In the present investigation, we study the survival of S. Enteritidis (CECT-4300) on strawberries after 2-min of various disinfection steps (NaClO (200 ppm), peracetic acid (PAA; 40 ppm), water-assisted UV-C (WUV-C), and the combination WUV-C and 40 ppm of PAA (WUV-C + PAA)) and after 5 days of cold storage (4 °C). Moreover, the pathogenic potential of the surviving bacteria, such as the ability to survive throughout the gastrointestinal tract (GI) and subsequently the capability to adhere to and invade Caco-2 cells, was tested at each sampling point. After 2-min of washing procedures, reductions of S. Enteritidis on strawberries were ≥1.2 log, with no significant differences among treatments. However, the use of WUV-C + PAA treatment achieved the highest reductions in washing water, in which S. Enteritidis was not detected (

Evaluation of a sanitizing washing step with different chemical disinfectants for the strawberry processing industry.

Strawberries are often consumed fresh or only receive minimal processing, inducing a significant health risk to the consumer if contamination occurs anywhere from farm to fork. Outbreaks of foodborne illness associated with strawberries often involve a broad range of microbiological agents, from viruses (human norovirus) to bacteria (Salmonella spp. and Listeria monocytogenes). The addition of sanitizers to water washes is one of the most commonly studied strategies to remove or inactivate pathogens on berries as well as avoid cross contamination due to reuse of process wash water. The risk posed with the safety issues of by-products from chlorine disinfection in the fruit industry has led to a search for alternative sanitizers. We evaluated the applicability of different chemical sanitizers (peracetic acid (PA), hydrogen peroxide (H2O2), citric acid (CA), lactic acid (LA) and acetic acid (AA)) for the inactivation of S. enterica, L. monocytogenes and murine norovirus (MNV-1) on strawberries. A control treatment with chlorine (NaClO) (100 ppm) was included. For each sanitizer, different doses (40, 80 and 120 ppm for PA and 1, 2.5 and 5% for H2O2, LA, AA and CA) and time (2 and 5 min) were studied in order to optimize the decontamination washing step. The best concentrations were 80 ppm for PA, 5% for H2O2 and 2.5% for organic acids (LA, AA and CA) after 2 min treatment. Results indicate that the sanitizers selected may be a feasible alternative to chlorine (100 ppm) for removing selected pathogenic microorganisms (P > 0.05), with reductions about ≥2 log for bacterial strains and ≥ 1.7 log for MNV-1. As the washing water may also increase the microbial counts by cross-contamination, we observed that no pathogenic bacteria were found in wash water after 5% H2O2 and 80 ppm PA after 2 min treatment. On the other hand, we also reported reductions about total aerobic mesophyll (TAM) (0.0-1.4 log CFU/g) and molds and yeasts (M&Y) (0.3-1.8 log CFU/g) with all alternative sanitizers tested. Strawberries treated did not shown significant differences about physio-chemical parameters compared to the untreated samples (initial). For this study, the optimal sanitizer selected was PA, due to the low concentration and cost needed and its microbiocidal effect in wash water and fruit. Notwithstanding the results obtained, the effect of PA in combination with other non-thermal technologies such as water-assisted ultraviolet (UV-C) light should be studied in future research to improve the disinfection of strawberries.

Patrones de prescripción de fármacos antihiperglucemiantes en pacientes ancianos en España: un estudio transversal nacional / Prescription patterns of antihyperglycemic drugs in elderly patients in Spain: a national cross-sectional study

ANTECEDENTES Y OBJETIVOS: Los pacientes ancianos con diabetes tipo 2 constituyen un grupo heterogéneo y creciente de sujetos en el que los objetivos terapéuticos y las prescripciones de los fármacos antihiperglucemiantes deben adaptarse a las enfermedades coexistentes y a su situación funcional y social. MÉTODOS: Realizamos un estudio transversal (desde febrero de 2014 a diciembre de 2014) para evaluar los patrones de prescripción y la inadecuación del tratamiento en pacientes con diabetes tipo 2 mayores de 65 años con al menos 6 meses de tratamiento con fármacos antihiperglucemiantes. RESULTADOS: Incluimos un total de 4.917 pacientes atendidos por 2.100 médicos de familia y 450 especialistas. Las prescripciones para la diabetes fueron monoterapia (21,2%), terapia dual (58,1%) y terapia triple (20,6%). Los patrones de prescripción más frecuentes fueron el de metformina en monoterapia (66,5%), metformina más inhibidores de la DPP-4 en terapia dual (77,3%) y, en terapia triple, fármacos orales (45,5%) y fármacos orales más insulina (45,8%). Un total de 1.272 (25,9%) pacientes presentaban riesgo de hipoglucemia grave, de los cuales 643 (50,6%) estaban en tratamiento con secretagogos (25%) o con insulina humana (25,6%). CONCLUSIONES: Los pacientes ancianos con diabetes tipo 2 reciben a menudo terapia antihiperglucemiante que comporta un alto riesgo de hipoglucemia. La sustitución de los secretagogos y de la terapia con insulina humana por una medicación más segura reduciría considerablemente los efectos secundarios del tratamiento de la diabetes en esta población

BACKGROUND AND OBJECTIVE: Elderly patients with type 2 diabetes represent a growing and heterogeneous group of subjects where treatment targets and antihyperglycemic drugs prescriptions should be tailored according to coexisting illnesses, functional and social domains. METHODS: We carried-out a national cross-sectional study (from February 2014 to December 2014) to assess prescription patterns and treatment inadequacy in patients with type 2 diabetes older than 65 years with at least 6 months of treatment with antihyperglycemic drugs. RESULTS: We included a total of 4,917 patients cared by 2,100 family physicians and 450 specialists. Diabetes prescriptions were monotherapy (21.2%), dual therapy (58.1%) and triple therapy (20.6%). The most common prescription patterns were metformin in monotherapy (66.5%), metformin plus DPP4 inhibitors in dual therapy (77.3%) and, in triple therapy, oral drugs (45.5%) and oral drugs plus insulin (45.8%). A total of 1,272 (25.9%) patients were at risk of serious hypoglycemia, 643 of them due to treatment with secretagogues (25%) or treatment with human insulin types (25.6%). CONCLUSIONS: Elderly patients with type 2 diabetes often receive antihyperglycemic therapy with higher risk of hypoglycemia. Substitution of secretagogues and human insulin therapy for safer medication could significantly reduce the adverse effects of diabetes treatment in this population

Microbial interaction between Salmonella enterica and main postharvest fungal pathogens on strawberry fruit.

The microbial interaction between Salmonella enterica and the main postharvest fungal pathogens of strawberries was evaluated. Inoculation of fungal suspension was done 2 (D2) and 1 (D1) day(s) before and at the same time (D0) as S. enterica. Fruits were stored at 20 °C and 4 °C. At both temperatures, Botrytis cinerea and Rhizopus stolonifer caused a decrease in S. enterica population. Treatments where the mould was inoculated (D2, D1 and D0) achieved a significant logarithmic reduction (P < 0.05) of S. enterica populations after 48 h (20 °C) and 14 days (4 °C) compared to fungal-uninoculated fruits (CK). Regarding temperature, average reductions were significantly higher at 4 °C (3.38 log10 CFU/wound) than at 20 °C (1.16 log10 CFU/wound) (P < 0.05). Average reductions comprising all treatments were 1.91 and 0.41 log10 CFU/wound for B. cinerea and R. stolonifer at 20 °C, and 3.39 and 3.37 log10 CFU/wound for B. cinerea and R. stolonifer at 4 °C. A linear log10 model was fitted in order to predict the inactivation rate (kmax, log10 CFU/h) of S. enterica. Inactivation rates were higher at 20 °C for D2 treatments than at 4 °C throughout the running time. The main inactivation rate was obtained for B. cinerea at 20 °C (0.160 ±â€¯0.027/h), which was found to have stronger inhibitory activity against S. enterica than R. stolonifer. Univariate analysis ANOVA was carried out to evaluate the effect of different external variables on the inhibition of S. enterica. Results found that single effects were significant (P < 0.05) except for the pH. The inhibitory effect caused by the action of moulds in conjunction with some environmental factors could indicate the potential interactions between strawberry fungal pathogens and S. enterica.

Prescription patterns of antihyperglycemic drugs in elderly patients in Spain: A national cross-sectional study. / Patrones de prescripción de fármacos antihiperglucemiantes en pacientes ancianos en España: un estudio transversal nacional.

BACKGROUND AND OBJECTIVE: Elderly patients with type 2 diabetes represent a growing and heterogeneous group of subjects where treatment targets and antihyperglycemic drugs prescriptions should be tailored according to coexisting illnesses, functional and social domains. METHODS: We carried-out a national cross-sectional study (from February 2014 to December 2014) to assess prescription patterns and treatment inadequacy in patients with type 2 diabetes older than 65 years with at least 6 months of treatment with antihyperglycemic drugs. RESULTS: We included a total of 4,917 patients cared by 2,100 family physicians and 450 specialists. Diabetes prescriptions were monotherapy (21.2%), dual therapy (58.1%) and triple therapy (20.6%). The most common prescription patterns were metformin in monotherapy (66.5%), metformin plus DPP4 inhibitors in dual therapy (77.3%) and, in triple therapy, oral drugs (45.5%) and oral drugs plus insulin (45.8%). A total of 1,272 (25.9%) patients were at risk of serious hypoglycemia, 643 of them due to treatment with secretagogues (25%) or treatment with human insulin types (25.6%). CONCLUSIONS: Elderly patients with type 2 diabetes often receive antihyperglycemic therapy with higher risk of hypoglycemia. Substitution of secretagogues and human insulin therapy for safer medication could significantly reduce the adverse effects of diabetes treatment in this population.

Occurrence of selected viral and bacterial pathogens and microbiological quality of fresh and frozen strawberries sold in Spain.

Strawberry production and exports have been increasing in Spain in recent decades. However, little information is available about their microbiological quality. Due to the growing concern about the microbial safety of these fruits, the objective of this investigation was to study the microbiological quality and the prevalence of the main foodborne pathogens on strawberries sold in Spain. Fresh (n = 152) and frozen (n = 31) samples were obtained from marketplaces and fields in 2017 and 2018. The samples were assayed for total aerobic mesophilic microorganisms (TAM), moulds and yeasts (M&Y), total coliforms (TC), Escherichia coli, Salmonella spp., Listeria monocytogenes as well as Norovirus (NoV) GI and GII. The microbiological counts ranged from <1.70 (detection limit, dl) - 5.89 log10 CFU/g (mean 3.78 log10 CFU/g) for TAM; 2.10-5.86 log10 CFU/g (mean 3.80 log10 CFU/g) for M&Y; and <0.70 (dl) - 4.91 log10 CFU/g (mean 2.15 log10 CFU/g) for TC in fresh strawberries. In frozen strawberries, the counts were <1.70 (dl) - 3.66 log10 CFU/g (mean 2.30 log10 CFU/g) for TAM; <1.70 (dl) - 2.76 log10 CFU/g (mean 1.82 log10 CFU/g) for M&Y; and <0.70(dl) - 1.74 log10 CFU/g (mean 0.77 log10 CFU/g) for TC. All the samples in this study tested negative for Salmonella spp., L. monocytogenes. E. coli and NoV GI and GII genome. A global overview of all the data was executed using Principal Component Analysis (PCA), and the results showed that the scores and loadings according to principal components 1 (PC1) and 2 (PC2) accounted for 75.9% of the total variance, allowing a distinction between fresh and frozen samples. The presence of moulds was significantly higher in the supermarket samples whereas the presence of total coliforms was significantly higher in the field samples (p < 0.05). Although pathogenic microorganisms were not found, preventative measures and prerequisites in the strawberry production chain must be considered in order to avoid possible foodborne diseases related to the microbiological quality of the fruit.

Efficacy of Pseudomonas graminis CPA-7 against Salmonella spp. and Listeria monocytogenes on fresh-cut pear and setting up of the conditions for its commercial application.

Pseudomonas graminis CPA-7 has been reported to control foodborne pathogens on fresh-cut apple, peach and melon. The first aim of this study was to assess its antagonistic activity against Salmonella spp. and L. monocytogenes on fresh-cut pear. CPA-7 was able to control both pathogens on fresh-cut pear stored in air conditions at 5, 10 and 20 °C. However, when CPA-7 antagonistic effect was tested by simulating commercial application (with antioxidant solution and passive modified atmosphere packaging), its effect decreased and no reductions of foodborne pathogens were reported at 10 °C. Therefore, the second aim was to optimise the antioxidant solution and the packaging in order to retain its antagonistic capacity. The selected antioxidant solution was 2% ascorbic acid +2% sodium citrate +1% CaCl2 according to growth and effect of CPA-7. Film permeability, which affects gas composition inside fruit packages, influenced CPA-7 efficacy. If the biopreservative strain is used, film has to be sufficiently gas permeable to allow CPA-7 function and at the same time to maintain product quality.

Biopreservative methods to control the growth of foodborne pathogens on fresh-cut lettuce.

Fruits and vegetables can become contaminated by foodborne pathogens such as Escherichia coli O157:H7, Salmonella and Listeria monocytogenes, and it has been demonstrated that current industrial sanitizing treatments do not eliminate the pathogens when present. Chemical control is widely used, but biological control appears to be a better solution, mainly using the native microbiota present on fresh produce. The first objective of this study was to isolate native microbiota from whole and fresh-cut produce and to determine whether these bacteria were antagonistic toward foodborne pathogens. A total of 112 putative antagonist isolates were screened for their ability to inhibit the growth of Salmonella enterica on lettuce disks. Five different genera reduced S. enterica growth more than 1-log unit at 20°C at the end of 3 days. When tested against L. monocytogenes 230/3, only Pseudomonas sp. strain M309 (M309) was able to reduce pathogen counts by more than 1-log unit. Therefore, M309 strain was selected to be tested on lettuce disks at 10°C against S. enterica, E. coli O157:H7 and L. monocytogenes. M309 strain was only able to reduce S. enterica and E. coli O157:H7 populations. The second objective was to test different biopreservative methods including M309 strain, Pseudomonas graminis CPA-7 (CPA-7), bacteriophages (Listex P100 and Salmonelex) and nisin at conditions simulating commercial applications against Salmonella and L. monocytogenes on fresh-cut lettuce. The addition of the biopreservative agents did not result in a significant reduction of Salmonella population. However, CPA-7 strain together with nisin reduced L. monocytogenes numbers after 6 days of storage at 10°C. The cocktail of Salmonella and L. monocytogenes was not markedly inactivated by their respective bacteriophage solutions. This study highlighted the potential of biocontrol, but the combination with other technologies may be required to improve their application on fresh-cut lettuce.

Effectiveness of a bacteriophage in reducing Listeria monocytogenes on fresh-cut fruits and fruit juices.

Listeria monocytogenes is a serious foodborne pathogen and new strategies to control it in food are needed. Among them, bacteriophages hold attributes that appear to be attractive. The objective of this study was to investigate the efficacy of the bacteriophage Listex P100 to control L. monocytogenes growth on melon, pear and apple products (juices and slices) stored at 10 °C. L. monocytogenes grew well in untreated fruit slices. In juices, the pathogen grew in untreated melon, survived in untreated pear and decreased in untreated apple. Phage treatment was more effective on melon followed by pear, but no effect on apple products was observed. Reductions of about 1.50 and 1.00 log cfu plug(-1) for melon and pear slices were found, respectively. In juices, higher reductions were obtained in melon (8.00 log cfu mL(-1)) followed by pear (2.10 log cfu mL(-1)) after 8 days of storage. L. monocytogenes in apple juice was unaffected by phage treatment in which the phage decreased to almost undetectable numbers. These results highlight that Listex P100 could avoid pathogen growth on fresh-cut and in fruit juices with high pH during storage at 10 °C. The combination with other technologies may be required to improve the phage application on high acidity fruits.

Presence and survival of Escherichia coli O157:H7 on lettuce leaves and in soil treated with contaminated compost and irrigation water.

Escherichia coli O157:H7 outbreaks associated with produce consumption have brought attention to contaminated compost manure, and polluted irrigation water as potential sources of pathogens for the contamination of these crops. The aim of this study was to determine the potential transfer of E. coli O157:H7 from soil fertilized with contaminated compost or irrigated with contaminated water to edible parts of lettuce together with its persistence in soil under field conditions in two different seasons (fall and spring). Moreover, its survival on lettuce sprinkled with contaminated irrigation water was evaluated, as well as the prevalence of aerobic mesophilic, Enterobacteriaceae and Pseudomonadaceae in control lettuce samples. Four treatments, contaminated compost, surface and sprinkle irrigation with contaminated water and uninoculated pots, were used in this work. Contaminated compost was applied to soil in the pots before lettuce was transplanted and contaminated irrigation water was applied twice and three times on the plants after the seedlings were transplanted, for sprinkle and surface irrigation, respectively. E. coli O157:H7 survived in soil samples for 9 weeks at levels, 4.50 log cfu gdw(-1) (dw, dry weight) in fall and 1.50 log cfu gdw(-1) in spring. The pathogen survives better in fall, indicating an important influence of environmental factors. E. coli O157:H7 population in lettuce leaves after sprinkle irrigation was very high (between 10(3) and 10(6) cfu g(-1)), but decreased to undetectable levels at field conditions. There was also transfer of E. coli O157:H7 from soil contaminated with compost or irrigated with contaminated water to lettuce leaves, mainly to the outer ones. The mean counts for aerobic mesophilic, Enterobacteriaceae and Pseudomonadaceae populations were also influenced by environmental conditions; higher levels were observed under fall conditions than in spring conditions. Contamination of lettuce plants in the field can occur through both contaminated composted manure and irrigation water and persist for several months.

Formulation development of the biocontrol agent Bacillus subtilis strain CPA-8 by spray-drying.

AIMS: To prepare commercially acceptable formulations of Bacillus subtilis CPA-8 by spray-drying with long storage life and retained efficacy to control peach and nectarine brown rot caused by Monilinia spp. METHODS AND RESULTS: CPA-8 24-h- and 72-h-old cultures were spray dried using 10% skimmed milk, 10% skimmed milk plus 10% MgSO(4) , 10% MgSO(4) and 20% MgSO(4) as carriers/protectants. All carriers/protectants gave good percentages of powder recovery (28-38%) and moisture content (7-13%). CPA-8 survival varied considerably among spray-dried 24-h- and 72-h-old cultures. Seventy-two hours culture spray dried formulations showed the highest survival (28-32%) with final concentration products of 1·6-3·3 × 10(9) CFU g(-1) , while viability of 24-h-old formulations was lower than 1%. Spray-dried 72-h-old formulations were selected to subsequent evaluation. Rehydration of cells with water provided a good recovery of CPA-8 dried cells, similar to other complex rehydration media tested. Spray-dried formulations stored at 4 ± 1 and 20 ± 1°C showed good shelf life during 6 months, and viability was maintained or slightly decreased by 0·2-0·3-log. CPA-8 formulations after 4- and 6 months storage were effective in controlling brown rot caused by Monilinia spp. on nectarines and peaches resulting in a 90-100% reduction in disease incidence. CONCLUSIONS: Stable and effective formulations of biocontrol agent B. subtilis CPA-8 could be obtained by spray-drying. SIGNIFICANCE AND IMPACT OF THE STUDY: New shelf-stable and effective formulations of a biocontrol agent have been obtained by spray-drying to control brown rot on peach.

Transfer of Listeria innocua from contaminated compost and irrigation water to lettuce leaves.

Many foodborne outbreaks of some pathogens such as Escherichia coli O157:H7, Salmonella or Listeria have been associated with the consumption of contaminated vegetables. Contaminated manure and polluted irrigation water are probable vehicles for the pathogens. The aim of this study was to determine the potential transfer of Listeria innocua from soil fertilized with contaminated compost or irrigated with contaminated water to the edible parts of lettuce grown on these soils together with its survival in lettuce and in soil under field conditions during two different seasons. Moreover, its survival on lettuce sprinkled with contaminated irrigation water was evaluated. L. innocua survived in soil samples for 9 weeks at high concentrations, 10(5) cfu gdw(-1) in fall and 10(3) cfu gdw(-1) in spring. Pathogen survived better in fall, indicating an important influence of temperature and humidity. L. innocua population in lettuce leaves was very high on lettuce leaves after sprinkling, but decreased to undetectable levels at field conditions. There was also transfer of L. innocua from soil contaminated with compost or irrigated with contaminated water to lettuce leaves, mainly to the outer ones. Survival profiles of L. innocua on lettuce and soil samples contaminated either by application of contaminated compost or surface irrigation water was similar. Our results indicated that contaminated compost and contaminated irrigation water can play an important role in the presence of foodborne pathogens on vegetables.

Microbiological quality of fresh lettuce from organic and conventional production.

Previously there was no available information on the levels of indicator bacteria and the prevalence of pathogens in fresh lettuce grown in organic and conventional farms in Spain. A total of 72 lettuce samples (18 farms for 4 repetitions each) for each type of the agriculture were examined in order to assess the bacteriological quality of the lettuces, in particular the prevalence of selected pathogens. The lettuce samples were analyzed for the presence of aerobic mesophilic, psychrotrophic microorganisms, yeasts and moulds, Enterobacteriaceae, mesophilic lactic acid bacteria, Pseudomonas spp. and presumptive Escherichia coli, Salmonella spp. and Listeria monocytogenes. The mean aerobic mesophilic counts (AM) were 6.35 +/- 0.69 log(10) cfu g(-1) and 5.67 +/- 0.80 log(10) cfu g(-1) from organic and conventional lettuce, respectively. The mean counts of psychrotrophic microorganisms were 5.82 +/- 1.01 log(10) cfu g(-1) and 5.41 +/- 0.92 log(10) cfu g(-1) from organic and conventional lettuce, respectively. Yeasts and moulds (YM) mean counts were 4.74 +/- 0.83 log(10) cfu g(-1) and 4.21 +/- 0.96 log(10) cfu g(-1) from organic and conventional lettuce, respectively. Lactic acid bacteria (LAB) were present in low numbers and the mean counts were 2.41 +/- 1.10 log(10) cfu g(-1) and 1.99 +/- 0.91 log(10) cfu g(-1) from organic and conventional lettuce, respectively. Pseudomonas spp. mean counts were 5.49 +/- 1.37 log(10) cfu g(-1) and 4.98 +/- 1.26 log(10) cfu g(-1) in organic and conventional lettuce, respectively. The mean counts for Enterobacteriaceae were 5.16 +/- 1.01 log(10) cfu g(-1) and 3.80 +/- 1.53 log(10) cfu g(-1) in organic and conventional lettuce, respectively. E. coli was detected in 22.2% (16 samples) of organic lettuce and in 12.5% (9 samples) of conventional lettuce. None of the lettuce samples was positive for E. coli O157:H7, L. monocytogenes and Salmonella spp. From the samples analyzed by principal component analysis (PCA) a pattern with two different groups (conventional and organic) can be observed, being the highest difference between both kinds of samples the Enterobacteriaceae count.

Effects of packaging type and storage temperature on the growth of foodborne pathogens on shredded 'Romaine' lettuce.

Fresh produce can be a vehicle for the transmission of pathogens capable of causing human illnesses and some of them can grow on fresh-cut vegetables. The survival and growth of Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes inoculated onto shredded lettuce was determined under modified atmosphere packaging conditions, at various storage temperatures. We also monitored changes in pH and gas atmospheres within the packages and the growth of psychrotrophic and mesophilic microorganisms. After pathogen inoculation, shredded lettuce was packaged in films of different permeability and stored at 5 and 25 degrees C. After 10 days at 5 degrees C populations of E. coli O157:H7 and Salmonella decreased approximately 1.00 log unit while L. monocytogenes increased about 1.00 log unit, in all package films. Moreover, the pathogens level increased between 2.44 and 4.19 log units after 3 days at 25 degrees C. Psychrotrophic and mesophilic bacteria had similar growth at both temperatures with higher populations in air than in the other atmospheres. The composition of the storage atmosphere within the packaging of lettuce had no significant effect on the survival and growth of the pathogens used in this study at refrigeration temperatures. The results obtained can be considered as a warning indicator, which reinforces the necessity for corrective measures to avoid contamination of vegetables.

Acid tolerance response induced in the biocontrol agent Pantoea agglomerans CPA-2 and effect on its survival ability in acidic environments.

The aim of this work was to optimize acid stress conditions for induction of acid tolerance response (ATR) in the biocontrol agent Pantoea agglomerans and study the effect of ATR induced on the ability to survive under acidic conditions. Initially, Pantoea agglomerans was grown in mild acidic conditions (pH 6.0, 5.5, 5.0 and 4.0) in order to induce ATR. The highest ATR was induced at initial pH of 5 using malic or citric acid. A first in vitro experiment was carried out. Thus, basal liquid medium at different pHs (3.0, 3.5, 4.0 and non-acidified) were then inoculated with acid-adapted and non-adapted inocula of P. agglomerans and survivals were examined during incubation at 25 or 4 degrees C. It was found that acid adaptation enhanced the survivals of Pantoea agglomerans CPA-2 cells at pH levels at which the cells were unable to grow (<3.5 and 4.0, at 25 and 4 degrees C, respectively). In contrast, in pH levels at which the cells were able to grow (pH 4.0 at 25 degrees C and non-acidified medium at 25 and 4 degrees C) no-differences were found between adapted and non-adapted cells. In in vivo tests, adapted and non-adapted cells were inoculated in wounds on mandarins and pome fruits. No differences were found between adapted and non-adapted cells and biocontrol efficacy was maintained. The present study demonstrated that exposure of Pantoea agglomerans to mild acidic conditions could induce acid resistance in this biocontrol agent.

Microbiological quality of fresh, minimally-processed fruit and vegetables, and sprouts from retail establishments.

A survey of fresh and minimally-processed fruit and vegetables, and sprouts was conducted in several retail establishments in the Lleida area (Catalonia, Spain) during 2005-2006 to determine whether microbial contamination, and in particular potentially pathogenic bacteria, was present under these commodities. A total of 300 samples--including 21 ready-to-eat fruits, 28 whole fresh vegetables, 15 sprout samples and 237 ready-to-eat salads containing from one to six vegetables--were purchased from 4 supermarkets. They were tested for mesophilic and psychrotrophic aerobic counts, yeasts and moulds, lactic acid bacteria, Enterobacteriaceae, presumptive E. coli and Listeria monocytogenes counts as well as for the presence of Salmonella, E. coli O157:H7, Yersinia enterocolitica and thermotolerant Campylobacter. Results for the fresh-cut vegetables that we analyzed showed that, in general, the highest microorganism counts were associated with grated carrot, arugula and spinach (7.8, 7.5 and 7.4 log cfu g(-1) of aerobic mesophilic microorganisms; 6.1, 5.8 and 5.2 log cfu g(-1) of yeast and moulds; 5.9, 4.0 and 5.1 log cfu g(-1) lactic acid bacteria and 6.2, 5.3 and 6.0 log cfu g(-1) of Enterobacteriaceae). The lowest counts were generally associated with fresh-cut endive and lettuce (6.2 and 6.3 log cfu g(-1) of aerobic mesophilic microorganisms; 4.4 and 4.6 log cfu g(-1) of yeast and moulds; 2.7 and 3.8 log cfu g(-1) lactic acid bacteria and 4.8 and 4.4 log cfu g(-1) of Enterobacteriaceae). Counts of psychrotrophic microorganisms were as high as those of mesophilic microorganisms. Microbiological counts for fresh-cut fruit were very low. Sprouts were highly contaminated with mesophilic (7.9 log cfu g(-1)), psychrotrophic microorganisms (7.3 log cfu g(-1)) and Enterobacteriaceae (7.2 log cfu g(-1)) and showed a high incidence of E. coli (40% of samples). Of the samples analyzed, four (1.3%) were Salmonella positive and two (0.7%) harboured L. monocytogenes. None of the samples was positive for E. coli O157:H7, pathogenic Y. enterocolitica or thermotolerant Campylobacter.

Improving low water activity and desiccation tolerance of the biocontrol agent Pantoea agglomerans CPA-2 by osmotic treatments.

AIMS: To study the improvement of tolerance to low water activity (aw) and desiccation during spray drying in Pantoea agglomerans cells subjected to mild osmotic stress during growth. METHODS AND RESULTS: The micro-organism was cultured in an unmodified liquid (control) or in aw-modified media, and viability of these cells was evaluated on unstressed (0.995) and 0.96 aw stressed solid media, in order to check total viability and aw stress tolerance respectively. Significant improvements in viability on unmodified medium were observed with cells grown for 24 h in NaCl 0.98 aw, glycerol 0.98 aw and 0.97 aw and for 48 h in NaCl 0.98 aw and 0.97 aw modified media. Both yield improvements and water stress tolerance were achieved with low aw media. Cells grown for 24 h in NaCl 0.98 aw or for 48 h in NaCl 0.98 aw, 0.97 aw and 0.96 aw, glucose 0.97 aw and glycerol 0.97 aw showed improved aw stress tolerance in comparison with control cells. The best results were obtained with NaCl treatments (0.98 aw and 0.97 aw) which also exhibited better survival rates than control cells during spray-drying process and maintained their efficacy against postharvest fungal pathogens in apples and oranges. CONCLUSIONS: NaCl treatments are very appropriate for improving P. agglomerans low aw tolerance obtaining high production levels and maintaining biocontrol efficacy. SIGNIFICANCE AND IMPACT OF THE STUDY: Improving stress tolerance of biocontrol agents could be an efficient way to obtain consistency and maintain efficacy of biological control under practical conditions.

Microbial quality of commercial 'Golden Delicious' apples throughout production and shelf-life in Lleida (Catalonia, Spain).

'Golden Delicious' apples taken from different points throughout the production chain and shelf-life were analysed for Enterobacteriaceae, thermotolerant coliforms, E. coli, E. coli O157:H7 and Salmonella spp. A total of 36 samples picked up in the orchard, 36 after storage and handling in the packinghouses and 144 from different retail stores were analysed using standardised techniques. Enterobacteriaceae counts were very variable. Pantoea spp. was the main genera isolated. The percentage of samples with thermotolerant coliforms was 16.6%, 22.2% and 10.4% after harvest, after handling in the packinghouse and in the stores, respectively. Strains belonging to Citrobacter, Enterobacter, Klebsiella and Escherichia were isolated. Three samples coming from orchards, five from the packinghouse and two from retailers harboured E. coli. However, none of the E. coli strains isolated had the virulence genes that are pathogenic for humans. None of the samples was Salmonella positive. This is the first study regarding microbial safety of fresh apples in the European Union (EU).

Optimization of growth conditions of the postharvest biocontrol agent Candida sake CPA-1 in a lab-scale fermenter.

AIM: To maximize the growth (expressed as number of viable cells per millilitre) of the postharvest biocontrol agent Candida sake CPA(-1) at laboratory scale conditions. METHODS AND RESULTS: Growth conditons (aeration, agitation speed and inoculum size) were studied in batch conditions in a 5 l fermenter using molasses and urea as growth medium. Consumption of sugars and urea were analysed. Fed-batch studies were also carried out. Glucose and fructose were consumed during the exponential growth phase and were depleted after 18 h of growth. On the contrary, C. sake cells assimilated sucrose during the stationary phase. There was not growth improvement when fed-batch technology was used. Addition of an extra amount of glucose or molasses after 18 h of growth did not contribute to increase final population. CONCLUSIONS: Maximum growth (about 8 x 10(8 )CFU ml(-1)) was obtained at batch fermentation after 30 h growth at 400 rev min(-1), 150 l h(-1) of air and initial concentration of 106 CFU ml(-1). SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained in this study are an approach for further upscaling of C. sake production.