Effect of Gamma Irradiation on Pathogenic Staphylococcus aureus in Packaged Ready-to-Eat Salads Treated with Biological Extracts.

Providing pathogen-free ready-to-eat (RTE) salads is critical for all consumers, especially individuals with weakened immunity. In this study, the efficacy of γ-irradiation on Staphylococcus aureus (S. aureus) in freshly packaged salads (4.24 log CFU/g) treated with essential oil (EO) and myrtle juice during 10 days of storage and their impact on organoleptic properties were investigated. EO was extracted by hydrodistillation and the chemical composition was analyzed by gas chromatography with Flame Ionization Detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS). Myrtle juice was prepared from fresh fruits. The cytotoxic effects of Thymus capitatus (T. capitatus) EO against a normal human umbilical vein endothelial cell (HUVEC) were assessed. GC/FID and GC-MS analysis of the thyme EO revealed the presence of 13 compounds, including carvacrol (79.55%) and p-cymene (7.93%) as major components. The EO was found to be noncytotoxic, with concentrations lower than 0.16 µL/mL. A reduction of more than 3 log CFU/g and a total inactivation of S. aureus were achieved with the combination of gamma irradiation at 0.5 kGy with myrtle juice at 6 µL/mL and EO at 0.08 µL/mL, respectively. The treatment of fresh RTE salads with thyme and myrtle juice was evaluated as acceptable by the sensory panel. The combined effect showed a synergistic potential on the inactivation of S. aureus.

Prevalence and growth potential of Listeria monocytogenes in innovative, pre-packed, plant-based ready-to-eat food products on the Belgian market.

In recent years, pre-packed ready-to-eat (RTE) food products on the Belgian market have shifted to a more plant-based composition due to a variety of reasons, including consumer concerns about health, animal welfare, and sustainability. However, similar to animal-based RTE foods, plant-based RTE foods can be susceptible to the presence and outgrowth of Listeria monocytogenes (L. monocytogenes). Three innovative, pre-packed, plant-based RTE food product categories on the Belgian market were identified based upon data gaps regarding the prevalence and growth potential of this pathogen. These were vegetarian and vegan deli sandwich slices (category 1), fresh-cut (mixes of) leafy vegetables (category 2), and multi-ingredient salad bowls (category 3). Reports on associated listeriosis outbreaks and recalls were collected and a comprehensive literature review on the prevalence of L. monocytogenes (i.e. detection in 25 g food) was performed. In addition, the prevalence of L. monocytogenes was also determined through an exploratory retail survey of ca. 50 different RTE products of each category. A batch was considered positive if L. monocytogenes was detected in a food item, either on the day of purchase, at the end of shelf life, or both. During the retail survey, L. monocytogenes was not detected in category 2 (0 out of 51 batches), while 1 out of 51 and 6 out of 48 batches were found positive for respectively category 1 and 3. The observed L. monocytogenes concentration did not exceed 10 CFU/g at any point in time in any batch. Furthermore, challenge tests were performed to determine the growth potential of L. monocytogenes in nine pre-packed, plant-based RTE food products (two to four different products of each category, and three different batches per product). After inoculation, products were stored for half of their shelf life at 7 °C and half of their shelf life at 9 °C (simulation of resp. retail and consumer storage). In six of the nine challenge tests executed, growth of L. monocytogenes was supported (i.e. growth potential ≥0.50 log10 CFU/g during shelf life). The highest growth potential was observed for fresh-cut iceberg lettuce (3.60 log10 CFU/g in 9 days), but a large variation regarding the growth potential of L. monocytogenes was noted both between and within the three studied pre-packed, plant-based RTE food product categories. This variation was mainly caused by differences in product composition, physicochemical product characteristics, present (competitive) microbiota such as lactic acid bacteria, applied preservation techniques, and shelf life.

Prevalence of Campylobacter spp., Salmonella spp., and Listeria monocytogenes, and Population Levels of Food Safety Indicator Microorganisms in Retail Raw Chicken Meat and Ready-To-Eat Fresh Leafy Greens Salads Sold in Greece.

The presence of microbial pathogens in foods compromises their safety resulting in foodborne illnesses, public health disorders, product recalls, and economic losses. In this work, 60 samples of chilled raw chicken meat and 40 samples of packaged ready-to-eat (RTE) fresh leafy greens salads, sold in Greek retail stores (butchers and supermarkets), were analyzed for the presence of three important foodborne pathogenic bacteria, i.e., Campylobacter spp., Salmonella spp., and Listeria monocytogenes, following the detection protocols of the International Organization for Standardization (ISO). In parallel, the total aerobic plate count (APC), Enterobacteriaceae, total coliforms, Escherichia coli, and staphylococci were also enumerated as hygiene (safety) indicator organisms. When present, representative typical colonies for each pathogen were biochemically verified, following the ISO guidelines. At the same time, all the Campylobacter isolates from chicken (n = 120) were identified to the species level and further phylogenetically discriminated through multiplex and repetitive sequence-based (rep) polymerase chain reaction (PCR) methods, respectively. Concerning raw chicken, Campylobacter spp. were recovered from 54 samples (90.0%) and Salmonella spp. were recovered from 9 samples (15.0%), while L. monocytogenes was present in 35 samples (58.3%). No Campylobacter was recovered from salads, and Salmonella was present in only one sample (2.5%), while three salads were found to be contaminated with L. monocytogenes (7.5%). The 65% of the Campylobacter chicken isolates belonged to C. jejuni, whereas the rest, 35%, belonged to C. coli. Alarmingly, APC was equal to or above 106 CFU/g in 53.3% and 95.0% of chicken and salad samples, respectively, while the populations of some of the other safety indicators were in some cases also high. In sum, this study unravels high occurrence percentages for some pathogenic and food safety indicator microorganisms in raw chicken meat and RTE fresh leafy greens salads sold in Greek retail, highlighting the need for more extensive microbiological control throughout the food production chain (from the farm/field to the market).

Possibilities of valorization of Gnetum spp leaves in modern gastronomy: Production and characterization of new vegetable tarts and salads.

Gnetum spp is a green creeper plant abundantly found in the Central African forests. Their leaves are eaten as vegetable by inhabitants. In order to valorize this vegetable in modern gastronomy, a survey was carried out in three towns of Cameroon to evaluate its importance in the feeding habits. The leaves were also sliced in two different forms, precooked, spin-dried and used for Gnetum tarts and salads production. 50, 100 and 150 g of thin sliced precooked leaves were used to prepare three salads and three tarts, keeping the other ingredients constant. Three additional tarts were prepared similarly using thinnest sliced precooked leaves. The final products were analyzed in terms of physiochemical, nutritional and sensorial properties. More than 96.9% of people investigated eat Gnetum leafy vegetables at least once per month. The survey study indicates that the transformation of Gnetum is mostly done by people within the age of 20 to 40 years old. Results of the physicochemical analyses showed that the total protein, lipid and carbohydrate contents increased in general with the increasing of the Gnetum leaf quantities used for preparation. The crude fiber contents of salads and tarts ranged from 52.00 ± 0.68 to 62.66 ± 1.26 and 29.33 ± 0.67 to 33.66 ± 0.47 g/100 g DW respectively. They were positively correlated with the quantity of Gnetum leaves used. The total phenolic contents, also increased significantly (p < 0.05) with the quantity of Gnetum leaves, from 182.45 ± 1.69 to 493.52 ± 2.10 mg/100 g DW for the salad and from 86.69 ± 4.08 to 283.21 ± 6.79 mg/100 g DW for the tart. The calculated energy density of tarts and salads permitted to classify these food products as low and high energy density foods respectively. The nutritional densities of produced tarts oscillated from 0.27 to 0.3 and that of salads from 0.58 to 0.71. With their nutritional values and the significant amount of fibers, Gnetum tarts and salads could be good new recipes to valorize the Gnetum leafy vegetables.

Biofortification of baby leafy vegetables using nutrient solution containing selenium.

BACKGROUND: Biofortification of vegetables is an important innovation technique in the horticultural sector. Vegetables can be a vector of different minor elements that have beneficial effects on human health. Selenium (Se) is an important element for human nutrition and plays a significant role in defence mechanisms. The aim of this work was to investigate the effect of Se in the nutrient solutions on the crop biofortification ability, yield, and quality parameters of four baby leafy vegetables destined to the minimally processed industry. Experiments were performed on lamb's lettuce, lettuce, wild rocket, and spinach. These crops were cultivated in the floating systems with nutrient solution enriched with 0, 2.6, 3.9, and 5.2 µmol L-1 Se provided as sodium selenate. RESULTS: At harvest, Se concentrations, yield, nitrate concentration, sugars, and some mineral elements were measured. Data collected and analyses showed that yield, nitrate, sucrose, and reducing sugars were not affected by Se treatments, even if varied among species. Se concentrations linearly increased in leaves of different species by increasing the Se concentration in the nutrient solution. Rocket was the species with the highest accumulation ability and reached a concentration of 11 µg g-1 fresh weight Se in plants grown with 5.2 µmol L-1 Se. CONCLUSION: A floating system with Se-enriched nutrient solution is an optimal controlled growing biofortification system for leafy vegetables. The accumulation ability decreased in different species in the order wild rocket, spinach, lettuce, and lamb's lettuce, highlighting a crop-dependent behaviour and their attitude to biofortification. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Nutritional Assessment of Ready-to-Eat Salads in German Supermarkets: Comparison of the nutriRECIPE-Index and the Nutri-Score.

Globally, an unbalanced diet causes more deaths than any other factor. Due to a lack of knowledge, it is difficult for consumers to select healthy foods at the point of sale. Although different front-of-pack labeling schemes exist, their informative value is limited due to small sets of considered parameters and lacking information on ingredient composition. We developed and evalauated a manufacture-independent approach to quantify ingredient composition of 294 ready-to eat salads (distinguished into 73 subgroups) as test set. Nutritional quality was assessed by the nutriRECIPE-Index and compared to the Nutri-Score. The nutriRECIPE-Index comprises the calculation of energy-adjusted nutrient density of 16 desirable and three undesirable nutrients, which are weighted according to their degree of supply in the population. We show that the nutriRECIPE-Index has stronger discriminatory power compared to the Nutri-Score and discriminates as well or even better in 63 out of the 73 subgroups. This was evident in groups where seemingly similar products were compared, e.g., potato salads (Nutri-Score: C only, nutriRECIPE-Index: B, C and D). Moreover, the nutriRECIPE-Index is adjustable to any target population's specific needs and supply situation, such as seniors, and children. Hence, a more sophisticated distinction between single food products is possible using the nutriRECIPE-Index.

Culture-dependent examination of the bacteriological quality of ready-to-eat African salads in Enugu metropolis, Nigeria and antibiotic resistance profile of associated bacteria.

This study investigated the bacteriological quality of ready-to-eat (RTE) African salads in Enugu metropolis, Enugu, Nigeria. A total of 10 samples of African salad were purchased from 10 different vendors in Enugu metropolis. The samples were purchased from Agbani Road, Ogbete, Mayor, Uwani, Kenyatta, Achara Layout, Obiagu and Timber. Isolation and enumeration of bacterial isolates were done using Nutrient agar, Eosin Methylene Blue (EMB) agar, Thiosulphate-citrate-bile salts-sucrose (TCBS) agar, Salmonella-Shigella Agar (SSA) and MacConkey agar, following standard methods. Identification of the bacterial isolates were done through biochemical tests and the Analytical Profile Index (API 20E) test kit. The antibiotic sensitivity of the bacterial isolates was also done using the Kirby Bauer disc diffusion method. Total culturable heterotrophic count was above 300 colonies across the samples. The highest bacterial counts recorded on EMB, SSA and TCBS across the samples were 6.3 × 106 CFU/g, 7.4 × 106 CFU/g and 1.21 × 107 CFU/g respectively. The identities of the organisms were; Salmonella spp., Staphylococcus aureus, Escherichia coli, Vibrio mimicus, Vibrio fluvialis, Vibrio cholerae, Vibrio parahaemolyticus and Vibrio hollisae. The prevalent organism across the samples was Vibrio spp. The antibiotic sensitivity test suggested that Vibrio spp. was resistant to Ampiclox and Amoxycillin but sensitive to Erythromycin, Pefloxacin and Septrin. From this study, it was discovered that consumers of RTE African salad from majority of the vendors across Enugu metropolis are at risk of severe food poisoning.

High Prevalence of Klebsiella pneumoniae in European Food Products: a Multicentric Study Comparing Culture and Molecular Detection Methods.

The Klebsiella pneumoniae species complex (KpSC) is a leading cause of multidrug-resistant human infections. To better understand the potential contribution of food as a vehicle of KpSC, we conducted a multicentric study to define an optimal culture method for its recovery from food matrices and to characterize food isolates phenotypically and genotypically. Chicken meat (n = 160) and salad (n = 145) samples were collected in five European countries and screened for the presence of KpSC using culture-based and zur-khe intergenic region (ZKIR) quantitative PCR (qPCR) methods. Enrichment using buffered peptone water followed by streaking on Simmons citrate agar with inositol (44°C for 48 h) was defined as the most suitable selective culture method for KpSC recovery. A high prevalence of KpSC was found in chicken meat (60% and 52% by ZKIR qPCR and the culture approach, respectively) and salad (30% and 21%, respectively) samples. Genomic analyses revealed high genetic diversity with the dominance of phylogroups Kp1 (91%) and Kp3 (6%). A total of 82% of isolates presented a natural antimicrobial susceptibility phenotype and genotype, with only four CTX-M-15-producing isolates detected. Notably, identical genotypes were found across samples-same food type and same country (15 cases), different food types and same country (1), and same food type and two countries (1)-suggesting high rates of transmission of KpSC within the food sector. Our study provides a novel isolation strategy for KpSC from food matrices and reinforces the view of food as a potential source of KpSC colonization in humans. IMPORTANCE Bacteria of the Klebsiella pneumoniae species complex (KpSC) are ubiquitous, and K. pneumoniae is a leading cause of antibiotic-resistant infections in humans. Despite the urgent public health threat represented by K. pneumoniae, there is a lack of knowledge of the contribution of food sources to colonization and subsequent infection in humans. This is partly due to the absence of standardized methods for characterizing the presence of KpSC in food matrices. Our multicentric study provides and implements a novel isolation strategy for KpSC from food matrices and shows that KpSC members are highly prevalent in salads and chicken meat, reinforcing the view of food as a potential source of KpSC colonization in humans. Despite the large genetic diversity and the low levels of resistance detected, the occurrence of identical genotypes across samples suggests high rates of transmission of KpSC within the food sector, which need to be further explored to define possible control strategies.

Contamination of home-grown and retail vegetables with Clostridioidesdifficile.

The opportunistic intestinal pathogen Clostridioides difficile is the number one cause of nosocomial diarrhea in humans. In this study, C. difficile was isolated from 26.7% of potatoes and 1.9% of salads from German retail. The majority of strains possessed toxinogenic PCR-ribotypes that are associated with human clinical cases pointing towards a potential risk to human health.

Tolerance of foodborne Acinetobacter spp. to sanitizer agents.

INTRODUCTION: The bacteria Acinetobacter spp. are extremely relevant in clinical settings. Recently, they have emerged as potential food-borne opportunistic pathogens. Their ability to form biofilms contributes to antibiotic resistance by generating an environment that facilitates the acquisition and transfer of resistance genes. Studies on the tolerance of Acinetobacter spp. from food sources to sanitizers used in the food industry and homes are necessary to help mitigate food contamination by these microorganisms. METHODOLOGY: Isolates from ready-to-eat salads (n = 11) and raw goat milk (n = 4) were evaluated for their tolerance to sodium hypochlorite (NaClO), quaternary ammonium compound/biguanide (QAC/BG), and peracetic acid (PAA). The Food and Drug Administration (FDA) recommends that the concentration of these sanitizers in food-processing equipment and utensils and other food-contact articles should not exceed 200 parts per million (ppm). RESULTS: The minimum inhibitory (MIC) and bactericidal (MBC) concentrations of NaClO were above 312.5 ppm for all isolates tested and ≥ 2,500 ppm for four isolates from salads. Only three isolates from salads and four isolates from goat milk were inhibited by an MIC lower than 200 ppm of PAA. QAC/BG presented the lowest MIC and MCB values (9.37/6.25  ppm for all isolates tested), suggesting that it is the most effective agent against the isolates used in this study. CONCLUSIONS: Our results demonstrate that Acinetobacter spp. isolates from food can be tolerant to the recommended concentrations of NaClO and PAA, which highlights the health risks to consumers.

Growth of Ready Meals in Australian Supermarkets: Nutrient Composition, Price and Serving Size.

Pre-prepared, or ready meals (frozen, chilled and shelf-stable) are increasingly available in supermarkets in developed countries. This study aimed to investigate how the range of ready meals in Australian supermarkets has changed from 2014 to 2020, and how products vary by price, serving size, nutrient composition and Health Star Rating. Product information was obtained from the FoodTrack™ packaged food database for the years 2014 to 2019 and from an instore audit of products available in Adelaide, Australia for 2020. There was a 13% annual average increase in the number of ready meals available in supermarkets. Serving size did not change (median 350 g, p-trend = 0.100) and price increased modestly from 2014 to 2020 (median $1.67 to $1.79/100 g, p-trend < 0.001), with chilled ready meals being the most expensive. A modest decrease in sodium density from 2014 to 2020 (median 275 to 240 mg/100 g, p-trend < 0.001) was seen. However, the category has a wide range in Health Star Ratings and nutrient composition, highlighting the importance of appropriate consumer choice to optimise health benefits. With the increasing availability of ready meals, global improvements within this category should be encouraged and consumers guided to choose healthier products.

Promoting Healthy Eating Behaviors by Incentivizing Exploration of Healthy Alternatives.

Incentive-based intervention programs aimed at promoting healthy eating behaviors usually focus on incentivizing repeating the desired behavior. Unfortunately, even when effective, these interventions are often short-lived and do not lead to a lasting behavioral change. We present a new type of intervention program focused on incentivizing exploration of new healthy alternatives rather than incentivizing repeated healthy behaviors. This intervention aims to help participants find long-lasting "personal treasures" -new foods that are both healthy and tasty for them. Our field study included a final sample of 48 students with low or medium daily consumption of fresh salads. Participants in the control group received a fixed payment for completing the program, while the participants in the incentivized exploration group received a lower fixed fee for completing the task and a bonus for each new salad they tried. Results show that participants in the incentivized exploration group reported eating more salads even 1 year after the program ended compared to the participants in the control group. Though preliminary, our results paint a promising picture for the successful application of incentivizing exploration interventions to promote healthy lifestyle.

Contamination of fresh produce sold on the Italian market with Cyclospora cayetanensis and Echinococcus multilocularis.

To investigate the presence of Cyclospora cayetanensis, Toxoplasma gondii and Echinococcus spp. in fresh produce sold in Italy, 324 locally produced 'ready-to-eat' (RTE) mixed-salad packages belonging to three brands and 324 berries packages (blueberries and blackberries imported from Peru and Mexico, respectively, and raspberries grown in Italy) were purchased at retail. Nine individual packages from each of the six types of fresh produce were collected monthly for one year, and with the same produce pooled, this resulted in a total of 72 pools for the whole year. Using microscopy (FLOTAC), a Cyclospora-like oocyst was detected in a blueberry sample and a taeniid egg was detected in a RTE-salad sample. Molecular tools confirmed these to be C. cayetanensis and Echinococcus multilocularis, respectively. Toxoplasma gondii was not detected in any of the samples. This study shows for the first time in Europe that imported berries on the Italian market may be contaminated with C. cayetanensis and RTE salads grown in Italy with E. multilocularis. The results indicate a new epidemiological scenario and highlight that current management of fresh produce, locally produced or imported, does not ensure products are free from parasite contamination.

Isolation and Characterization of a Virulent Bacteriophage for Controlling Salmonella Enteritidis Growth in Ready-to-Eat Mixed-Ingredient Salads.

ABSTRACT: Ready-to-eat vegetable salads have gained popularity worldwide. However, the microbial safety of these salads is a health concern, primarily due to Salmonella Enteritidis contamination during the growing, harvesting, processing, and handling of produce. In this study, a bacteriophage-based strategy was developed to control Salmonella Enteritidis growth in mixed-ingredient salads. The lytic Salmonella-specific phage SapYZU01 was isolated from a soil sample from a suburban vegetable field in Yangzhou (People's Republic of China). SapYZU01 has a short latent period, a large burst size, and a lytic effect against 13 Salmonella Enteritidis strains isolated from various sources (human samples, pork, deli foods, chickens, and chicken meat). The SapYZU01 genome did not contain virulence or antibiotic resistance genes. SapYZU01 significantly decreased the viability of Salmonella Enteritidis cells in iceberg lettuce, chicken meat, and mixed-ingredient (lettuce plus chicken) salads at 37 and 25°C. Bacterial levels in the salad decreased significantly (by 4.0 log CFU/g) at 25°C after treatment of contaminated lettuce before salad preparation with SapYZU01 at a multiplicity of infection (MOI) of 100. Bacterial levels were decreased by 3.8 log CFU/g at 25°C in lettuce plus chicken salads treated after the salad preparation with SapYZU01 at an MOI of 100. In contrast, treating cooked chicken meat with SapYZU01 at an MOI of 100 before mixing it with contaminated lettuce decreased the bacterial level of the salad by 1.2 log CFU/g at 25°C. These findings indicate the potential application of SapYZU01 as a natural biocontrol agent against Salmonella Enteritidis in mixed-ingredient salads. However, both the treatment method and the bacteriophage MOI must be considered when using this lytic bacteriophage in mixed-ingredient salads.

Expiration Date of Ready-to-Eat Salads: Effects on Microbial Load and Biochemical Attributes.

When minimally processed vegetables reach their expiration date, expose an increased microbial load. This includes mainly spoilage microorganisms but also foodborne pathogens, thus affecting the quality and safety of highly consumed ready-to-eat salads. A total of 144 ready-to-eat salads from the Cypriot market were analyzed in an attempt to determine the effects of the expiration date on the microbial load and plant metabolic variables of the salads. Possible correlations between them were also investigated for the first time. Furthermore, the impacts of the season (winter, summer), salad producing companies and type of salad and/or their interactions with the tested parameters were investigated. Results revealed that the microbial load (mainly spoilage microorganisms, such as Pseudomonas spp., yeasts and molds) increased towards the end of the shelf life. The microbial load was differentiated among the five salad producers and/or the salad types, highlighting the importance of a common and safe sanitation-processing chain in the preparation of ready-to-eat salads. Summer was the season in which Escherichia coli counts were found to be higher for plain lettuce, while Staphylococcus spp. was increased numbers for the lettuce+endive/radicchio, lettuce+rocket and lettuce+chives type of salads. Additionally, an increased Staphylococcus spp. was observed for plain rocket salads in winter. All samples examined were found negative for Salmonella enterica and Listeria monocytogenes. Moreover, carbon dioxide production and damage indexes (hydrogen peroxide and lipid peroxidation) increased on expiration date on both winter and summer seasons, indicating plant tissue stress at the end of shelf life. These findings indicate that the expiration date and relevant shelf life of processed vegetables are important parameters to be considered when postharvest management is applied to these products, ensuring safety and quality.

The Possibilities of Using Ultrasonically Activated Streams to Reduce the Risk of Foodborne Infection from Salad.

In this study, we investigated the effects of an ultrasonically activated stream (UAS) on the removal of microbial contaminants from spinach leaves. The microbial loads on samples cleaned with and without UAS were enumerated using the cell culture method and compared against unwashed samples on day 0 and day 6 after cleaning. The effects of UAS cleaning on leaf quality were also examined through both macroscopic and microscopic inspection, as well as measurement of the electrolyte leakage rate. Results showed that the microbial load on samples cleaned with UAS for 2 min was significantly lower on day 6 after cleaning than on those treated without ultrasound. Comparison between the cleaning effects of UAS for 40 s versus 2 min indicated that a cleaning duration of 2 min allowed sufficient time for UAS to disaggregate and detach the microbial contamination more effectively. In this case, the induction of bacteria into a viable but non-culturable state does not affect the shelf-life test results as much as it does with a 40 s clean. UAS cleaning for 2 min did not produce significant surface damage, which can affect overall leaf quality. These findings highlight the potential of UAS systems in the salad industry to improve the microbiological quality and shelf life of salads.

Polyphasic study of antibiotic-resistant enterobacteria isolated from fresh produce in Germany and description of Enterobacter vonholyi sp. nov. isolated from marjoram and Enterobacter dykesii sp. nov. isolated from mung bean sprout.

Forty-two antibiotic-resistant enterobacteria strains were isolated from fresh produce obtained from the northern German retail market. A polyphasic characterization based on both phenotypic and genotypic methods was used to identify predominant strains as Citrobacter (C.) gillenii, C. portucalensis, Enterobacter (En.) ludwigii, Escherichia (E.) coli and Klebsiella (K.) pneumoniae. 38.1% of the enterobacteria strains were resistant to tetracycline, while 23.8% and 9.5% of strains were resistant to streptomycin and chloramphenicol, respectively. A high percentage of Klebsiella (100%), Enterobacter (57.1%) and Citrobacter (42.9%) strains were also resistant to ampicillin, with some strains showing multiple resistances. For unequivocal species identification, the genomes of thirty strains were sequenced. Multilocus sequence analysis, average nucleotide identity and digital DNA-DNA hybridization showed that Enterobacter strains E1 and E13 were clearly clustered apart from Enterobacter species type strains below the species delineation cutoff values. Thus, strains E1T (=DSM 111347T, LMG 31875T) represents a novel species proposed as Enterobacter dykesii sp. nov., while strain E13T (=DSM 110788T, LMG 31764T) represent a novel species proposed as Enterobacter vonholyi sp. nov. Strains often possessed different serine ß-lactamase genes, tet(A) and tet(D) tetracycline resistance genes and other acquired antibiotic resistance genes. Typical plasmid replicon types were determined. This study thus accurately identified the enterobacteria from fresh produce as species belonging to the genera Citrobacter, Enterobacter, Escherichia and Klebsiella, but also showed that these can carry potentially transferable antibiotic resistance genes and may thus contribute to the spread of these via the food route.

Microbiological Quality of Ready-to-Eat Leafy Green Salads during Shelf-Life and Home-Refrigeration.

The market of ready-to-eat leafy green salads is experiencing a noticeable growth in Europe. Since they are intended to be consumed without additional treatments, these ready-to-eat products are associated with a high microbiological risk. The aim of this work was to evaluate the microbiological quality and safety of ready-to-eat leafy green salads sold in widespread supermarket chains in Lazio, Italy, on the packaging date during shelf-life and during home-refrigeration. The study also aimed to determine the differences between low-, medium-, and high-cost products. Salmonella spp. and L. monocytogenes were chosen as safety indicators as specified by European regulations while total aerobic mesophilic bacteria and Escherichia coli were chosen as quality indicators as suggested by national guidelines. Analyses were performed following the ISO standards and in parallel for the evaluation of total aerobic mesophilic bacteria, with an alternative colorimetric system, the Micro Biological Survey method, in order to propose a simple, affordable and accurate alternative for testing the microbiological quality of products, especially suitable for small and medium enterprises and on-site analyses. The study revealed high, unsatisfactory, total bacterial loads in all analyzed samples on the packaging date and expiry date and a very high prevalence of Salmonella spp. (67%) regardless of the selected varieties and cost categories; L. monocytogenes was not recovered aligning with the results obtained in other studies.

Effects of Intrinsic and Extrinsic Visual Cues on Consumer Emotion and Purchase Intent: A Case of Ready-to-Eat Salad.

With increasing demand for ready-to-eat (RTE) fresh vegetables, it is important to understand how visual information cues, both intrinsic and extrinsic, affect consumer perception of these products. This study developed an emotional and wellness lexicon related to RTE salads. Subsequent questionnaires with images of salads were used to quantify consumer (N = 150) emotional and hedonic perceptions related to green color shade, shape/size of pieces, multicolor scheme, product name, and packaging. The different visual cues significantly impacted emotions and their intensities. Qualitatively, feelings of health and wellness predominated across salad samples. Negative emotions were more influenced by size of piece and green-color (intrinsic), while positive emotions were influenced by viewing salads of multiple colors (intrinsic) and packaging (extrinsic). Pale green salads were generally less liked than darker green ones. Values, in one case, ranged from 4.39 to 7.28 (on a 9-point hedonic scale), but naming the product ("iceberg lettuce") did raise the lowest score to 5.75. The addition of vegetables with orange and purple colors to the salad mix had a positive impact on the perception of pale green salads. This study demonstrated that intrinsic and extrinsic visual cues significantly influenced consumer emotions, hedonic perception and purchase intent of RTE salads, but the effects of extrinsic cues were generally less prominent.

Fruit and Vegetable Consumption of US Adults by Level of Variety, What We Eat in America, NHANES 2013-2016.

BACKGROUND: Dietary guidance encourages consuming a variety of fruit and vegetables (FVs), which has been associated with higher FV intake and nutrient adequacy. Dietary intake of adults in the United States has not been described in the context of variety. OBJECTIVES: The objective of this study was to describe FV consumption of adults in the United States by level of FV variety. METHODS: One day of dietary intake data of adults aged ≥20 y (n = 10,064) in What We Eat in America, NHANES 2013-2016 were used. FV variety was the count of foods consumed that contributed to total FV intake. Each FV was counted only once; a mixed dish counted as 1. Variety levels were high (≥5 items, n = 2316); moderate (3-4 items, n = 3423); or low (1-2 items, n = 3746). Differences between each level of variety were compared by t test. RESULTS: Among the low, moderate, and high levels, total FV intakes were 1.4, 2.6, and 4.4 cup equivalents (CE), respectively. CE amounts of FVs consumed were 0.3, 0.6, and 1.4 of vegetables excluding potatoes; 0.2, 0.3, and 0.3 of potatoes; 0.3, 0.6, and 1.2 of fruit; and 0.4, 0.4, and 0.5 from mixed dishes, respectively; percentages of each level reporting intake were 34%, 64%, and 89% for vegetables excluding potatoes; 23%, 34%, and 32% for potatoes; 22%, 49%, and 75% for fruit; and 72%, 71%, and 72% for mixed dishes, respectively. CONCLUSIONS: Those with more variety of FV intake include whole FVs more frequently and in higher amounts. These results support suggestions for encouraging more FVs at snacks and as side dishes and salads at meals to increase total intake.