María I Gil

• Bachelor of Pharmacy, PhD of Biology
• Professor at Spanish National Research Council

This tender, developed under a self‐task mandate from the BIOHAZ Panel, analysed the characteristics of the water and the practices followed by the European food business operators (FBOs) to maintain process water quality used during the post‐harvest handling and processing operations for fresh and frozen fruits, vegetables and herbs (ffFVHs) using...

A commercial phage biocontrol for reducing Listeria monocytogenes has been described as an effective tool for improving fresh produce safety. Critical challenges in the phage application must be overcome for the industrial application. The validation studies were performed in two processing lines of two industry collaborators in Spain and Denmark,...

Since 2020, there is a new European Regulation (EU, 2020/741) on minimum requirements for water reuse, where routine and validation monitoring requirements (log reductions of indicator microorganisms and reference pathogens) have been established. Many reclamation facilities that are already in operation might have difficulties to comply with these...

A commercial phage biocontrol for reducing Listeria monocytogenes has been described as an effective tool for improving fresh produce safety. Critical challenges in the phage application must be overcome for the industrial application. The validation studies were performed in two processing lines of two industry collaborators in Spain and Denmark,...

The presence of human enteric viruses in produce has extensively been reported. However, the significance of the quality of process water (PW) used by the produce industry and the viral inactivation capacity of water disinfection agents used to maintain the microbiological quality of PW has received limited attention. This study evaluates the antiv...

In the present study, the occurrence of indicator antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) both in the influent and the effluent of four Spanish wastewater treatment plants (WWTPs) was monitored for 12 months, and the susceptibility profiles of 89 recovered extended spectrum β-lactamase (ESBL)-producing Escherichia...

Some water disinfection treatments, such as chlorine and chlorine dioxide, used in the fresh-cut industry to maintain the microbiological quality of process water (PW), inactivate bacterial cells in the water but they also lead to the induction of an intermediate state between viable and non-viable known as viable but non-culturable (VBNC) state. V...

Frozen vegetables have emerged as a concern due to their association with foodborne outbreaks such as the multi-country outbreak of Listeria monocytogenes serogroup IVb linked to frozen corn. The capacity of L. monocytogenes to colonize food-processing environments is well-known, making the bacteria a real problem for consumers. However, the signif...

Lettuce is one of the most commonly consumed leafy vegetables worldwide and is available throughout the entire year. Lettuce is also a significant source of natural phytochemicals. These compounds, including glycosylated flavonoids, phenolic acids, carotenoids, the vitamin B groups, ascorbic acid, tocopherols, and sesquiterpene lactones, are essent...

A case study of 15 wastewater treatment plants (WWTPs) at a full-scale was assessed for the risks of disinfection byproduct (DBP) formation, mainly the regulated trihalomethanes (THMs) and haloacetic acids (HAAs) and chlorate as an inorganic byproduct regulated recently in the EU. Raw wastewater from large, medium/small urban areas were treated wit...

The virological quality of process water (PW) used by the produce industry has received limited attention. As a first step to overcoming technical limitations in monitoring viruses in PW, the analytical performance of ultrafiltration was assessed to concentrate viral particles from 20 L of spiked PW. The selected method used for sample concentratio...

The elaboration of guidelines for the industry to establish minimum concentration to prevent cross-contamination during washing practices based on operational limits is the core of the recommended criteria for the use of sanitizers. Several studies have evidenced that sanitizers reduced the levels of foodborne pathogens. However, they might lead to...

The new European regulation on minimum quality requirements (MQR) for water reuse (EU, 2020/741) was launched in May 2020 and describes the directives for the use of reclaimed water for agricultural irrigation. This Regulation will be directly applicable in all Member States from 26 June 2023. Since its publication in 2020, concerns have raised abo...

The present study aimed to characterize wastewater fractions obtained after the wet extraction of proteins from legumes. In addition, the suitability of wastewater fractions for the potential recovery of high value-added compounds was also examined, and consequently, the prevention of the environmental impact of these wastes was explored. Similar t...

Sanitizers are an effective measure to maintain the microbiological safety of fresh produce process water. Proper water disinfection management is critical to avoid cross-contamination during the washing of fresh produce. Chlorine remains the most common sanitizer, and recent research deals, among other topics, with the comparison of different type...

An accurate sensor for peracetic acid (PAA) is needed to monitor and control the disinfection of fresh produce wash water. Inaccurate measurements can result in underdosing and unsafe produce or overdosing with huge cost implications. In this study, five methods were compared for measuring PAA in process water from washing apples, tomatoes, red swe...

One solution to current water scarcity is the reuse of treated wastewater. Water reuse systems have to be examined as a whole, including the efficacy of water-reclamation treatments and the operation steps from the wastewater inlet into the WWTP to the irrigation endpoint, including the irrigated crop. In this study, the monitoring of human enteric...

In the washing operations of fruit and vegetables, the maintenance of an appropriate range of pH in the water when using chlorine is crucial to ensure the maximum concentration of hypochlorous acid (HOCl), the form of chlorine with the highest antimicrobial activity. In this study, the effect of two inorganic acids (phosphoric and sulfuric) and two...

La industria de alimentos vegetales consume grandes volúmenes de agua de buena calidad y genera grandes cantida­des de agua residual. Uno de los sistemas que se pueden aplicar para reducir el consumo y el vertido de agua es la reutilización del agua de lavado. Para llevar a cabo la reutilización del agua sin comprometer la seguridad microbiológica...

The significance of viable but non-culturable (VBNC) cells in the food industry is not well known, mainly because of the lack of suitable detection methodologies to distinguish them from dead cells. The study aimed at the selection of the method to differentiate dead and VBNC cells of Listeria monocytogenes in process wash water (PWW) from the frui...

Antimicrobial treatment of fresh produce wash water can enable water reuse by avoiding microbial cross-contamination. In this study, the efficacy of chlorine dioxide (ClO2; 2–3 mg/L) to maintain the microbiological quality of process wash water in a tomato packinghouse was assessed. Different parameters were measured, including the physicochemical...

The use of reclaimed water for irrigation after disinfection can provide significant environmental, social and economic benefits and solve the problem of water scarcity. The occurrence of disinfection by-products (DBPs) as pollutants in irrigation water has been highlighted as a health risk of emerging concern since they can be uptaken by the plant...

The washing stage from a bell pepper commercial packinghouse was assessed to study some of the critical control points related to bacterial cross-contamination. The washing line comprised two overhead spray bars applications: a pre-wash step without peroxyacetic acid (PAA), and a wash step with PAA. The physicochemical characteristics of the wash w...

Growth of L. monocytogenes is among the most important factors affecting the risk of human listeriosis. In ready to eat leafy greens, the use of anti-Listeria treatments represents a good alternative to inhibit growth during storage. Several commercially available antimicrobial agents have been suggested as effective intervention strategies. Among...

Fresh products can become contaminated with disease-causing microorganisms and chemical contaminants at every step of the production and processing chain and in a variety of ways, including through contact with contaminated process water. Water quality is critical to prevent microbial and chemical risks in any of the postharvest and processing oper...

Abstract Fresh produce can become contaminated with disease‐causing microorganisms and chemical contaminants at every step of the production and processing chain and in a variety of ways, including through contact with contaminated process water. Water quality is critical to prevent microbial and chemical risks in any of the postharvest and process...

https://authors.elsevier.com/a/1ZNE33PY0vU4j6 Anyone using this link before August 30, 2019 will be taken directly to the final version of the article on ScienceDirect

Fresh produce causes most foodborne outbreaks in the USA, and it is also considered a hazardous food product in other areas of the world such as Europe. The outbreaks attributed to fresh produce increase the focus of producers on hygiene to minimize exposure to food hazards. The fresh produce industry has the urgent need to detect if there are prod...

Antimicrobial treatment of fresh produce process wash water (PWW) needs to be optimized to improve the microbiological safety while minimizing the presence of disinfection by-products (DBPs) that can be adsorbed by the washed produce. In this study, the occurrence of DBPs including trihalomethanes (THMs) and chlorate in the PWW of shredded lettuce,...

During the processing of fresh produce, washing with chlorinated water may result in an unacceptable source of chlorate as a disinfection by-product (DBP) in the finished product. The differential ability for the uptake of chlorate by different fresh-cut products during washing was evaluated. Results showed that chlorate uptake was affected by the...

The metabolism of phenolic compounds is a key factor in the development of wound-induced enzymatic browning of fresh-cut lettuce. In the present study, the lettuce midribs discriminant metabolites, selected in a previous untargeted metabolomics study, were thoroughly identified. Our results showed that their basal contents correlated with browning...

The goal of the present study was to establish free chlorine operational limits for the disinfection of different types of fresh-cut produce wash water using sodium hypochlorite (NaClO). The proposed operational limits in the wash water are based on both the effectiveness of microbial inactivation and the occurrence of disinfection by-products (DBP...

Reclaimed water obtained from urban wastewater is currently being used as irrigation water in water‐scarce regions in Spain. However, wastewater can contain enteric viruses that water reclamation treatment cannot remove or inactivate completely. In the present study, greenhouse‐grown baby lettuce ( Lactuca sativa L.) was irrigated with secondary tr...

Reclaimed wastewater used for agricultural irrigation should meet specific microbiological standards in order to prevent microbial contamination of the irrigated produce. The objective of this study was to evaluate the suitability of chlorine dioxide (ClO2) for the disinfection of secondary-treated municipal wastewater and its subsequent use for ov...

The effects of factors such as weather conditions, leaf age and irrigation water disinfection on the main bacterial genera (total bacterial, Enterobacteriaceae and Pseudomonas) of baby spinach were studied. Culture-dependent and independent quantification techniques were compared. Cultivation was carried out over two consecutive trials in commercia...

A complete untargeted metabolomics study was developed to identify biomarkers related to the browning offresh-cut lettuce which is the main cause of quality loss. For this purpose, UPLC-MS-QTOF analysis was opti-mized to explore the metabolome of 30 selected cultivars of romaine lettuce with different browning suscept-ibility harvested at three diffe...

The safety of agricultural products might be influenced by different factors such as climate change and global trends. An unequivocal consequence associated to climate change is global warming, with a prediction of an average increase in global temperature by 2100 between 1.8 and 4°C. Among other climate effects, the global warming will also be ass...

The efficacy of electrochemical treatment for the disinfection of process wash water, using boron-doped diamond electrodes, as well as its suitability for the fresh-cut produce industry, has been evaluated. Process water containing different levels of organic matter (chemical oxygen demand (COD), around 60, 300, 550±50 and 750±50 mg L⁻¹) obtained f...

The contamination of pathogenic bacteria through irrigation water is a recognized risk factor for fresh produce. Irrigation water disinfection is an intervention strategy that could be applied to reduce the probability of microbiological contamination of crops. Disinfection treatments should be applied ensuring minimum effective doses, which are ef...

Rarefaction curves of sequencing samples. (A) irrigation water samples (IW), (B) soil samples (soil), (C) baby spinach samples (crop). CT is the control treatments (without chlorine dioxide) and ClO2 represents chlorine dioxide treatments. (1, IW-CT; 2, IW-CT; 3, IW-CT; 4, IW-CT; 5, IW-CT; 6, IW-CT; 7, IW-CT; 8, IW-CT; 9, IW-CT; 10, IW-CT; 11, IW-C...

Composition of bacterial families of untreated and ClO2 treated samples of irrigation water (IW), soil (Soil) and baby spinach (Crop). Bacterial community is the average of 5 individual samples. Data shown are families that comprised at least 1% of the sequences in at least one sample of a given agronomic habitat. (PDF)

Process wash water and washed products from three different fresh produce processing lines were characterized at commercial scale. Different physicochemical and microbiological characteristics of wash water were measured. Great variability between processing lines on the physicochemical quality of process wash water was observed, caused in part by...

This chapter reviews the implications of water quality in the fresh produce industry and the associated problems from the food safety and environmental perspectives including the wastewater generated. Guidelines and national regulations focused on Good Agricultural Practices (GAP), Good Handling Practices (GHP), and Good Manufacturing Practices (GM...

Background: Irrigation water disinfection reduces the microbial load but it might lead to the formation and accumulation of disinfection by-products (DBPs) in the crop. If DBPs are present in the irrigation water, they can accumulate in the crop, particularly after the regrowth, and be affected by the postharvest handling such as washing and stora...

Background: Treatments for the disinfection of irrigation water have to be evaluated by demonstration tests carried out under commercial settings taking into account not only their antimicrobial activity but also the potential phytotoxic effects on the crop. The consequences of the treatment of irrigation water with chlorine dioxide (ClO2 ) used f...

Irrigation water has been highlighted as a potential contamination source of fresh produce with foodborne pathogens. Water disinfection treatments can be used to improve its microbiological safety. Growers should ascertain the minimum effective disinfectant doses able to achieve the desired microbiological goals. Furthermore, potential unwanted eff...

To establish the association between microbial indicators and the presence of foodborne pathogens in irrigation water, Escherichia coli was enumerated using two quantification methods (plate counts and PMA-qPCR) and presence/absence of pathogenic microorganisms, including five strains from the Shiga toxigenic E. coli (O157:H7, O26, O103, O111 and O...

The effects of relative humidity (RH), fluctuating climate conditions, inoculum size and carrier on the survival of Salmonella enterica serovar Typhimurium on baby lettuce in environmental test chambers were studied. Buffered peptone water (BPW), distilled water (DW), and irrigation water (IW) were compared as inoculum carriers. Additionally, survi...

Fresh fruit and vegetables are a major source of biologically active compounds essential for human wellbeing. They are, however, perishable living products that require coordinated actions by growers, storage operators, processors, and retailers to maintain their quality and reduce food loss and waste. Recent advances in shelf life extension have b...

Strong off-odor development is still one of the major problems associated with quality loss of baby spinach stored in MA with low O2 and high CO2. Freshness has been generally evaluated by sensory techniques that allow the description of aromatic profiles but it does not identify the responsible compound(s). An approach including sensory analysis a...

Enzymatic browning is one of the main causes of quality loss in lettuce as a prepared and ready to eat cut salad. An untargeted metabolomics approach using UPLC-ESI-QTOF-MS was performed to explain the wound response of lettuce after cutting and to identify the metabolites responsible of browning. Two cultivars of Romaine lettuce with different bro...

The main goal of the present study was to describe the volatile profile of three different basil genotypes (Genovese and Green and Purple Iranian), and the impact that water stress (75% and 50% field capacity) and storage time (up to 7 days) have under mild refrigerated conditions. The chromatographic profile pointed to three different chemotypes:...

Solar radiation has been identified as a stress factor affecting phyllosphere associated bacteria colonization and survival during primary production. In the present study, the impact of different solar radiation doses on the phyllosphere microbiota of red-pigmented baby leaf lettuce cultivated in open field under commercial conditions was evaluate...

The objective of this study was to investigate if different growing season climates influenced the quality of fresh-cut lettuce. Different cultivars and harvests of iceberg and romaine lettuce grown over 26 months were processed and stored for 11 d in active modified atmosphere (MA) and then transferred to air for 24 h at 7 °C. Pearson correlation...

Salinity is one of the most important stress factors in crop production, particularly in arid regions. This research focuses on the effect of salinity on the growth of lettuce plants; three solutions with different levels of salinity were considered and compared (S1 = 50, S2 = 100 and S3 = 150 mM NaCl) with a control solution (Ct = 0 mM NaCl). The...

The popularity of the consumption of fresh ready-to-eat (RTE) products has increased globally. Simultaneously, the number of outbreaks and cases of foodborne illness associated with the consumption of contaminated fresh produce continues to escalate. Thus, it becomes clear that fresh and fresh-cut vegetables are not processed in ways that effective...

Cultivar selection is of great importance for the fresh-cut industry and new cultivars and breeding lines with low response to cutting are constantly required. However, there is no standardized protocol for lettuce breeding and processing companies to select those cultivars most appropriate for the specific requirements of fresh-cut. The objective...

Browning of fresh-cut romaine lettuce was inhibited in modified atmosphere (MA) packaging with low O2 and moderate CO2 concentrations during storage. This study explains the control mechanisms of MA causing differences in phenolic substrates and oxidative enzymes related to browning of two cultivars of romaine lettuce. Modified atmosphere decreased...

The shift from local to global food markets as well as other food safety concerns such as the pressure of climate change has increased the demand on current horticultural production systems to guarantee the microbiological (e.g., control of Salmonella and pathogenic E. coli) and chemical (e.g., pesticide residues) safety of fresh produce. To deal w...

Introduction The shelf-life of fresh-cut lettuce after storage is limited by several factors that affect its quality and lead to consumer rejection. Different metabolic events occur after cutting as an abiotic stress response. Objectives This study aims to explore the metabolome of iceberg lettuce and to understand the changes related to storage t...

Aims: To assess the prevalence of enteric viruses in different irrigation water sources and in the irrigated produce, and the possible links with microbiological and physicochemical water characteristics. Methods and results: The prevalence and levels of Escherichia coli, Norovirus (NoV) genogroup I (GI) and II (GII), as well as Hepatitis A viru...

Electrolyzed water (EW) is known by its bactericidal efficacy and capability to oxidize organic matter. The present research evaluated the efficacy of recently developed electrolytic cells able to generate higher concentration of reactive oxygen species using lower power and salt concentration than conventional cells. This study tested the inactiva...

Minimally processed products are generally exposed to low temperature and uncontrolled light conditions during the supply chain. The positive effect of low temperature on quality of baby spinach is widely reported, but there is little information available about the light effect. The objective of this study was to obtain insight about the cause-eff...

The use of fecal indicators such as Escherichia coli has been proposed as a potential tool to characterize microbial contamination of irrigation water. Recently, not only the type of microbial indicator but also the methodologies used for enumeration have been called into question. The goal of this study was to assess the microbial quality of diffe...

Traditionally, microbiological testing for food safety assurance in fresh-cut industries relied on end product to evaluate compliance with microbial standards. Replacement of end-product testing by a preventive system is being recommended by competent authorities for the production of safe food. In the fresh-cut processing industry, there is still...

The objective of this study was to evaluate if time of day for harvest and delay before processing affected the quality of baby spinach. Three times of the day for harvest (8:30, 13:00 and 17:30. h as H1, H2 and H3, respectively) and three times of delay before processing (DP) (3, 24 and 48. h as DP3, DP24 and DP48, respectively) were studied. Two...

This study examined the effects of salt stress on the physiological responses and postharvest quality characteristics of fresh sweet basil (Ocimum basilicum L.). Plants were treated with 40 and 80 mM NaCl for 25 days during cultivation in 2014. Two green genotypes, Green Iranian and Genovese basil, were studied after harvest, and while two Iranian...

The suitability of high power ultrasound (HPU, 20 kHz, 0.28 kW/l) combined with residual chemical sanitizers for water reconditioning was studied. A synergetic disinfection effect was observed when HPU was combined with peroxyacetic acid (PAA) or a commercial mix of organic acids and phenolic compounds (OA/PC). In recycled water (RW) with a chemica...