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Aims The aims of this study were to: (i) estimate the effectiveness of ultraviolet radiation (UV) and sulphuric acid‐based fertilizer (SA), at reducing levels of generic Escherichia coli in surface irrigation water and on produce and surface soil in open produce fields; and (ii) describe the population dynamics of generic E. coli in produce fields. Methods and Results Spinach and cantaloupe plots were randomly assigned to control, UV or SA treatment groups. Irrigation water was inoculated with Rifampicin‐resistant E. coli prior to treatment. More than 75% of UV‐ and SA‐treated tank water samples had counts below the detection limit, compared to a mean count of 3·3 Log10 CFU per ml before treatment. Levels of Rifampicin‐resistant E. coli in soil and produce both increased and decreased over 10–15 days after irrigation, depending on the plot and time‐period. Conclusions UV and SA treatments effectively reduce the levels of E. coli in surface irrigation water. Their effectiveness at reducing contamination on produce was dependent on environmental conditions. Applying wait‐times after irrigation and prior to harvest is not a reliable means of mitigating against contaminated produce. Significance and Impact of the Study The results are of timely importance for the agricultural industry as new FSMA guidelines require producers to demonstrate a low microbial load in irrigation water or allow producers to apply a wait‐time to mitigate the risk of contaminated produce.

Among the non-thermal food technologies, high pressure processing (HPP) is currently the most widespread intervention in the juice industry. The study herein was conducted to challenge a wide range...

Raw honey contains a diverse microbiota originating from honeybees, plants, and soil. Some gram-positive bacteria isolated from raw honey are known for their ability to produce secondary metabolites that have the potential to be exploited as antimicrobial agents. Currently, there is a high demand for natural, broad-spectrum, and eco-friendly bio-fungicides in the food industry. Naturally occurring antifungal products from food-isolated bacteria are ideal candidates for agricultural applications. To obtain novel antifungals from natural sources, we isolated bacteria from raw clover and orange blossom honey to evaluate their antifungal-producing potential. Two Bacillus velezensis isolates showed strong antifungal activity against food-isolated fungal strains. Antifungal compound production was optimized by adjusting the growth conditions of these bacterial isolates. Extracellular proteinaceous compounds were purified via ammonium sulfate precipitation, solid phase extraction, and RP-HPLC. Antifungal activity of purified products was confirmed by deferred overlay inhibition assay. Mass spectrometry (MS) was performed to determine the molecular weight of the isolated compounds. Whole genome sequencing (WGS) was conducted to predict secondary metabolite gene clusters encoded by the two antifungal-producing strains. Using MS and WGS data, we determined that the main antifungal compound produced by these two Bacillus velezensis isolates was iturin A, a lipopeptide exhibiting broad spectrum antifungal activity.

An Irrigation Water Quality Database was developed to help assess the microbiological quality of irrigation water used in fruit and vegetable production in 15 counties in New York (NY) State. Water samples from Tennessee (TN) were also included in the database. Four water quality parameters, quantified generic Escherichia coli, specific conductance, pH, and turbidity, were tested. Ground, reservoir, and running water were sampled over 2 years (2009 and 2010), covering three seasons each year (spring, summer, and fall). TN data are for all three seasons in 2010 only. Overall in NY (254 total samples), ground water had a geometric mean of 1 most probable number (MPN)/100 ml, reservoir water had a geometric mean of 8 MPN/100 ml, and running water had a geometric mean of 52 MPN/100 ml. Overall in TN (63 total samples), ground water had a geometric mean of 1 colony forming unit (CFU)/100 ml, reservoir water had a geometric mean of 5 CFU/100 ml, and running water had a geometric mean of 38 CFU/100 ml. These values are all below the 126 MPN/100 ml United States Environmental Protection Agency's Ambient Water Quality Standards (AWQS) standard for fresh water. The presence of E. coli had very weak but sometimes statistically signficiant correlatation with water specific conductance, pH, and turbidity, depending on the water source but the r-squared effect was not strong enough to make the other measurements a substitute for testing specifically for E. coli in water.

Six thermo-acidophilic, spore-forming strains were isolated from a variety of juice products and were characterized genetically and phenotypically. According to 16S rRNA and rpoB gene phylogenetic analyses and average nucleotide identity comparisons against the species demarcation cutoff at Alicyclobacillus . The isolates were designated FSL-W10-0018T, FSL-W10-0037, FSL-W10-0048, VF-FSL-W10-0049T, FSL-W10-0057 and FSL-W10-0059T. All six isolates were Gram-positive, motile, rod shaped, contained menaquinone 7 as the major respiratory quinone and had ω-cyclohexane C17 : 0 as a major fatty acid. They were all able to grow aerobically in a range of acidic and moderate thermal conditions. Only isolates FSL-W10-0048 and VF-FSL-W10-0049T were able to produce guaiacol. The following names are proposed for the three new species: Alicyclobacillus mali sp. nov. (type strain FSL-W10-0018T =DSM 112016T=NCIMB 15266T); Alicyclobacillus suci sp. nov (VF-FSL-W10-0049T=DSM 112017T=NCIMB 15265T); and Alicyclobacillus fructus sp. nov. (FSL-W10-0059T=DSM 112018T=NCIMB 15264T).

The objectives of this research were to study the effect of DMDC (0–250 ppm) on quality and shelf life of mango and passion fruit smoothie during cold storage. The correlation between microbial population (total microorganisms, yeast and mold, E. coli and S. aureus) and DMDC concentration using zero-order kinetic and first-order kinetic was also determined. In addition, the effect of DMDC compared with pasteurization (90 °C, 100 s) on quality of mixed mango and passion fruit smoothie during the cold storage (4 °C) was studied. The results showed that microbial inactivation was best-described by first-order kinetic model due to a higher coefficient of determination (R2). In addition, DMDC did not affect the decreasing trend of total soluble solid, color difference (∆E*) and total phenolic compound as compared to control during the cold storage. DMDC also hindered the increasing trend in microbial population and prevented the loss of antioxidant activity (DPPH and FRAP assays) and total flavonoid content and decreased the PPO activity as compared with the control during the cold storage. In summary, DMDC showed the potential to maintain the quality and to extend the shelf life of mango and passion fruit smoothie during cold storage.

Staphylococcus epidermidis and Staphylococcus aureus, two bacterial strains commonly associated with biofilm-related medical infections and food poisoning, can rapidly colonize biotic and abiotic surfaces. The present study investigates the ability of anodic alumina surfaces with nanoporous surface topography to minimize the attachment and biofilm formation mediated by these pathogenic bacterial strains. Early attachment and subsequent biofilm development were retarded on surfaces with nanopores of 15-25 nm in diameter compared to surfaces with 50-100 nm pore diameter and nanosmooth surfaces. After 30 min of incubation in nutritive media, the biomass accumulation per unit surface area was 2·93 ± 1·72 µm3 µm-2 for the 15 nm, 3·49 ± 1·97 µm3 µm-2 for the 25 nm, as compared to 14·04 ± 6·39 µm3 µm-2 for the nanosmooth, 11·88 ± 9·72 µm3 µm-2 for the 50 nm and 12·09 ± 11·84 µm3 µm-2 for the 100 nm surfaces respectively. These findings suggest that anodic alumina with small size nanoscale pores could reduce the incidence of staphylococcal biofilms and infections, and shows promise as a material for a variety of medical applications and food contact surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: This paper reports on a simple, robust and scientifically sound method to reduce attachment and biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis to abiotic surfaces using a carefully designed nanoscale topography. This approach can help to reduce the incidence of staphylococcal biofilms and infections without imposing selective stresses on bacteria, thus preventing the creation of resistant strains.

Psychrotolerant growth of Listeria monocytogenes in ready-to-eat (RTE) foods increases the risk to food safety, particularly when spoilage does not occur prior to L. monocytogenes growth of >1 log CFU/g. The purpose of this study was to evaluate the relative rates of quality deterioration and L. monocytogenes growth in six product systems (tomatoes, apples, fresh-cut cantaloupe, fresh-cut lettuce, baby spinach, and commercially processed turkey slices) under various conditions of refrigeration temperatures, atmospheres, and quality. Cantaloupe and spinach leaves supported >1 log CFU/g growth of L. monocytogenes before product spoilage at both 4 and 9°C. In some cases, conditions that improved microbial quality by extending shelf life also allowed L. monocytogenes growth of >1 log CFU/g before deterioration due to microbial spoilage. For example, storage with modified atmosphere packaging enhanced L. monocytogenes growth relative to spoilage microbiota in lettuce leaves (1.0-log increase 7 days before spoilage). In contrast, the use of secondary quality produce (i.e., apples, tomatoes, and lettuce with physical damage) reduced shelf life and, consequently, limited the time for L. monocytogenes proliferation. Therefore, spoilage cannot be considered a fail-safe indicator or proxy for limitation of shelf life across refrigerated RTE products.

The mean intake (500 mg/day) of branched chain fatty acids (BCFA) in western countries is from dairy products and beef. We hypothesized that Asian countries with low dairy consumption have an alternative source of BCFA and report the characterization of nātto and selected fermented foods for BCFA content. Nātto BCFA averaged 0.6 (range 0.21–1.43) mg BCFA per g natto (wet weight) and was highly variable. Nātto major BCFA are C14-17 iso- and anteiso-BCFA similar to fluid milk. BCFA concentrations were 1.00 ± 0.64%, 1.63 ± 0.72% and 0.65 ± 0.07%, of total fatty acids in nātto, shrimp paste and fish sauce, respectively. In contrast, saturates, monounsaturates, and major polyunsaturates were more constant (coefficient of variation = 21%, 26% and 4% compared to 64% for nātto BCFA). Detection of fatty acid ethyl esters were confirmed in miso and found in homemade kimchi. Habitual nātto and/or fermented seafood consumption could support BCFA intakes similar to dairy consumption.

Paecilomyces niveus has long been recognized as an important heat-resistant mold (HRM) causing spoilage in thermally processed apple products. With the recent discovery that P. niveus causes an apple disease called Paecilomyces rot, there is a need to evaluate the possibility that the spores can be introduced via infected fruit and survive thermal processing to contaminate apple products. Previously, research characterizing P. niveus survival and spoilage has been based on simple inoculation of cultured ascospores directly into juice. To determine whether ascospores formed in infected fruit survive through thermal processing with rotating vacuum evaporation (2.5 h, 70 °C), apples infected with P. niveus were used to make apple juice concentrate. Viable P. niveus was quantified in samples taken throughout the apple juice concentrate process: in cider, centrifuged juice, apple solids, and in juice made from concentrate. Additionally, the concentration of the mycotoxin patulin was determined in a subset of samples. Results show that P. niveus survived juice concentration. The thermal process used significantly reduced P. niveus (P = 0.0017); from an average of 5.5 log CFU L−1 in the initial cider made from diseased fruit to an average of 1.5 log CFU L−1 in single strength apple juice diluted from concentrate. Ascospores were observed at a greater abundance than intact asci throughout the concentration process. Patulin concentrations at all stages of apple juice concentration exceeded the United States’ regulatory defect action level of 50 ppb. This is the first report that apples infected with P. niveus can survive and remain viable in finished apple products and that patulin is produced in these apples. It raises important questions about the use of damaged and infected fruit as a source of HRM which contribute to spoilage and mycotoxins in apple juice concentrate.

Active packaging can enhance the performance of natural antimicrobials in controlling food spoilage and waste, while addressing consumer demands for cleaner labels. Yet, synergies are system dependent, with some conditions counterintuitively promoting antagonistic effects. In particular, metal chelators can improve performance of certain natural antimicrobials and have been incorporated in nonmigratory metal chelating active packaging technologies. However, the influence of chelating ligand chemistry on antimicrobial efficacy has not been investigated in microbial spoilage models. The effect of three commercial chelating resins on the growth of Alicyclobacillus acidoterrestris ATCC 49025, a thermoduric acidophilic spore-former, in growth media and apple juice was investigated. Dowex MAC-3, Chelex 100, and Lewatit TP260 were used as models for metal chelating active packaging containing carboxylic acid (CA), iminodiacetic acid (IDA), and aminomethylphosphonic acid (AMPA) ligands. Diameters (CA = 472.4 ± 117.2 μm, IDA = 132.93 ± 26.71 μm, and AMPA = 498.3 ± 29.24 μm), dissociation kinetics (CA = 6.44 ± 0.109, IDA = -0.977 ± 9.94, AMPA = 7.43 ± 0.193), and metal chelating capacities (CA = 1.16 × 10-4 mol/g, IDA = 1.52 × 10-3 mol/g, and AMPA = 4.67 × 10-4 mol/g) were used to distinguish differences in antimicrobial efficacies. Growth of A. acidoterrestris in acidified Potato Dextrose Broth over 24 hr with chelating resins indicated early death phase for CA and IDA resins and bactericidal for AMPA resin. However, viability in commercial apple juice with the inclusion of nisin and chelating resins was variable, with IDA resin significantly (P < 0.05) increasing viability while the effect of CA and AMPA resins remained elusive. This work emphasizes the importance of biological repeatability and correct statistical modeling in identifying conditions under which the antimicrobial intervention of nisin in real food systems, such as acidic beverages and juices, are synergistic or antagonistic. PRACTICAL APPLICATION: New technologies to control microbial food spoilage and waste need to be explored to address consumers on-going demands for reducing additive use. Solid support bound metal chelators can both promote and control microbial growth when used in conjunction with nisin, a natural antimicrobial. This work explores how system conditions can render a given technology either synergistic or antagonistic, and highlights the importance of sufficient biological replicates in experimental design.

The principal objective of the study was the isolation and identification of bacteria that are present in mature bee bread (BB) and dried (ready for selling and consumption) bee pollen (BP). Obtained isolates were screened for their potential to inhibit select human pathogenic bacteria and their ability to produce enzymes of particular industrial importance. Four and five samples of BP and BB, respectively, were used for the study. In total, 81 strains of bacteria were isolated, and 34 (42%) of them exhibited antagonistic interactions with at least one reference strain of pathogenic bacteria, namely Staphylococcus aureus ATCC 25923, Staphylococcus aureus ATCC 29213, Staphylococcus epidermidis 12228, Pseudomonas aeruginosa ATCC 27857, and Escherichia coli ATCC 25922. The sequencing of the 16S rRNA gene revealed that all strains producing antimicrobials belong to the genus Bacillus spp., and among them, five species were identified: B. pumilus (n = 17), B. altitudinis (n = 9), B. licheniformis (n = 4), B. subtilis (n = 2), and B. safensis (n = 1). Furthermore, 69, 54, 39, and 29 of the strains exhibited lipolytic, proteolytic, cellulolytic, and esterolytic activity, respectively. Alpha amylase and beta galactosidase activity were rarely observed, and none of the strains produced laccase. The outcomes of the study revealed that BP and BB can be considered potential sources of bacteria producing antimicrobial agents and/or enzymes of particular industrial importance. Of course, additional research is required to verify this hypothesis, but the results of preliminary studies are promising.

This study aimed at investigation of the antimicrobial potential of ethanolic extracts of bee bread (BB) and bee pollen (BP) and suspensions of these products in MHB (Mueller Hinton Broth). We covered 30 samples of BP and 19 samples of BB harvested in Polish apiaries. Slightly lower activity was observed against Gram-negative bacteria compared to Gram-positive staphylococci. BB extracts exhibited higher inhibitory potential with minimum inhibitory concentration (MIC) values in the range from 2.5 to 10% (v/v) against Staphylococcus aureus ATCC 25923 and ATCC 29213. Most active BB extracts, namely, BB6, BB11 and BB19, effectively inhibited growth of clinical isolates of S. aureus (n = 9), including MRSA (methicillin resistant Staphylococcus aureus) strains (n = 3) at concentrations ranging from 2.5 to 5.0% (v/v). Minimal bactericidal concentration (MBC) values were in the same range of concentrations, however, a shift from 2.5 to 5.0% (v/v) was observed for some products. The most active BP extracts inhibited the growth of reference strains of S. aureus at a concentration of 5% (v/v). Up to the concentration of 20% (v/v) three and seven BP extracts were not able to inhibit the growth of S. aureus ATCC 29213 and S. aureus ATCC 25923 respectively. The growth of staphylococci was also importantly inhibited in suspensions of the products in MHB. No correlation between phenolic content and antimicrobial activity was observed.

Cleaning and sanitation are critical to maintaining safe and high-quality food production. Monitoring these activities is important to ensure proper execution of procedure and to assure compliance with regulatory guidelines., Rapid ATP testing and microbiological enumeration are two common methods to monitor the effectiveness of cleaning and sanitation in the food industry. In this study, ATP testing and microbiological enumeration were implemented at a tofu production facility with the goal of improving cleaning practices and overall plant hygiene. Results from ATP monitoring were used to target areas of the production environment needing additional cleaning; ATP results were verified by microbiological enumeration of aerobic microorganisms, lactic acid bacteria, and yeasts and molds. Products from the production line were enumerated for the same microorganisms to determine if there was an impact on product quality. After the implementation of ATP monitoring and targeted cleaning, there was a statistically lower proportion of swabs that failed to meet established sanitary requirements for ATP, aerobic microorganisms, and lactic acid bacteria (P

This document provides an overview of juice-related foodborne outbreaks between 1922-2019. This information is useful to juice processors to aid in the identification of pertinent microorganisms, and also reviews locations, venues of juice preparations, and severity of juice-associated outbreaks.

Wine and alcoholic apple cider are commonly back-sweetened with unpasteurized juice to produce fresh, natural, and palatable sweetened alcoholic beverages. Foodborne pathogens may be introduced from unpasteurized juice into alcoholic beverages through this back-sweetening process. Although foodborne pathogens generally do not survive under low pH conditions or a high alcohol environment, the die-off of these pathogens has not been established to ensure the microbiological safety of the products. To establish the holding conditions that would provide the required 5-log pathogen reduction requirements for these back-sweetened beverages, we evaluated the survival of three common foodborne pathogens, E. coli O157:H7, Salmonella enterica, and Listeria monocytogenes, in modified white grape juice and apple juice models. White grape juice and apple juice were modified with hydrochloric acid and sodium hydroxide and with ethanol to achieve conditions that are similar to back-sweetened white wine and alcoholic apple cider in regard to pH and ethanol content. Foodborne pathogen cocktails were inoculated separately into modified juice models, and their survival in the juice models was recorded over a 96-h period. Our results show that a combination of low pH and high ethanol content resulted in faster pathogen die-off compared with higher pH and lower ethanol conditions. The holding times required for different combinations of pH and ethanol concentration for each juice model to achieve a 5-log reduction were reported. This research provides data to validate pathogen die-off to comply with juice hazard analysis and critical control point 5-log pathogen inactivation requirements for back-sweetened wine and alcoholic apple cider. HIGHLIGHTS

Increasing consumer demand for high-quality foods has driven adoption by the food industry of non-thermal technologies such as high pressure processing (HPP). The technology is employed as a post-packaging treatment step for inactivation of vegetative microorganisms. In order to evaluate HPP inactivation of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in acid and acidified juices and beverages, pressure tolerance parameters were determined using log-linear and Weibull models in pH-adjusted apple juice (pH 4.5) at 5 °C. A commercial processing HPP unit was used. The Weibull model better described the inactivation kinetics of the three tested pathogens. According to estimates from the Weibull model, 1.5, 0.9, and 1.5 min are required at 600 MPa to produce 5-log reductions of E. coli, Salmonella, and L. monocytogenes, respectively, whereas according to the log-linear model, 3.2, 1.8, and 2.1 min are required. The effects of process conditions were verified using commercial products (pH between 3.02 and 4.21). In all tested commercial juices or beverages, greater than 5-log reductions were achieved for all tested pathogens using HPP process conditions of 550 MPa for 1 min. These findings demonstrate that the HPP conditions of 600 MPa for 3 min, typically used by the food industry provide an adequate safety margin for control of relevant vegetative pathogens in acid and acidified juices and beverages (pH 4.5). Results from this study can be used by food processors to support validation studies and may be useful for the future establishment of safe harbors for the HPP industry.

An emerging need for new classes of antibiotics is, on the one hand, evident as antimicrobial resistance continues to rise. On the other hand, the awareness of the pros and cons of chemically synthesized compounds' extensive use leads to a search for new metabolites in already known reservoirs. Previous research showed that Paenibacillus strain (P. alvei MP1) recovered from a buckwheat honey sample presented a wide spectrum of antimicrobial activity against both Gram-positive and Gram-negative pathogens. Recent investigation has confirmed that P. alvei MP1 (deposited at DDBJ/ENA/GenBank under the accession WSQB00000000) produces a proteinaceous, heat-stable compound(s) with the maximum antimicrobial production obtained after 18 hours of P. alvei MP1 growth in LB medium at 37 &deg, C with continuous shaking at 200 RPM. The highest activity was found in the 40% ammonium sulfate precipitate, with high activity also remaining in the 50% and 60% ammonium sulfate precipitates. Moderate to high antimicrobial activity that is insensitive to proteases or heat treatment, was confirmed against pathogenic bacteria that included L. monocytogenes FSL &ndash, X1-0001 (strain 10403S), S. aureus L1 &ndash, 0030 and E. coli O157: H7. Further studies, including de novo sequencing of peptides by mass spectrometry, are in progress.

PurposeHigh-acid liquid foods are a substrate in which foodborne pathogens can maintain their viability. In this research an experimental design was conducted to optimize the parameters for high pressure processing (HPP) of apple juice (pH 3.76).Design/methodology/approachJuice was inoculated with cocktails of Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes. Pressures ranging from 139 to 561 MPa and dwell times between 39 and 181 s were challenged.FindingsPressures above 400 MPa achieved a greater than 5-log reduction in all pathogen cocktails regardless of the dwell time. L. monocytogenes was more sensitive to HPP at a pressure of 350 MPa and dwell times equal to or beyond 110 s. E. coli O157:H7 and S. enterica exhibited similar resistance; the number of log reductions in the central point (350 MPa/110 s) ranged from 2.2 to 3.7. The first-order mathematical model better fitted experimental data for E. coli O157:H7 and S. enterica. In regard to L. monocytogenes, the second-order model better fitted this pathogen's reduction.Practical implicationsFruit juices are usually high pressure processed at approximately 600 MPa. For pathogenic reduction, the use of milder parameters may save energy and maintenance costs. The results herein exhibited could assist the apple juice industry with more effective applications of HPP.Originality/valueThe findings of this study demonstrate that relatively moderate pressures can be successfully used to assure the safety of apple juice.

Purpose High pressure processing (HPP) has been widely used for high-acid (pH Design/methodology/approach Grape juice was inoculated with five strain cocktails of Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes. In total, 11 trials were carried out based on a Central Composite Rotational Design (CCRD). The pressure (P), ranging from 319 to 531 MPa, and dwell time (t), from 35 to 205 s, were tested. The performance of the combinations (P × t) was evaluated by pathogen challenge microbiological assays. Findings E. coli O157:H7 was more resistant to HPP than S. enterica. L. monocytogenes did not grow in unprocessed juice (before HPP). Findings demonstrated that moderate pressures (~400 MPa) and short dwell times (~2 min) were effective in achieving a greater than 5-log reduction in the pathogens of reference. Practical implications Because the maintenance costs of equipment exponentially increase with pressure beyond 600 MPa, significant reductions in process pressure are highly desirable. Originality/value The results of this study can supplement the dearth of information on the applicability of high pressure as a Concord grape juice processing technology in terms of the pathogens inactivation. Furthermore, the use of a cocktail of five strains of pathogens inoculated in Concord grape juice to challenge different HPP parameters has not been reported.

Fungal spoilage in processed foods remains a challenge for food manufacturers despite the increasing availability of diverse processing and formulation strategies used to control foodborne microorganisms. Physiological features of yeasts and molds contribute to their tolerance to thermal processing, acidity, desiccation, and oxygen and nutrient limitations. These features variably include growth form, cell wall structure, cytoplasmic composition, cell membrane-bound proteins, and secretion of secondary metabolites. Collectively, these mechanisms contribute to the ability of fungi to disperse, survive, and propagate in highly restrictive food environments. The diversity of fungal growth and survival mechanisms has resulted in organisms adapted to nearly all food environments; although, only a small subset of fungi are particularly suited for spoilage of a given product. The relationship between the individual physiology and metabolic capabilities of a yeast or mold and the product's specific physicochemical attributes and processing history determines spoilage potential. Explicit characterization of the fungal features responsible for this extremotolerance contributes to more targeted and effective control strategies.

Reducing biofouling while increasing lubricity of inserted medical catheters is highly desirable to improve their comfort, safety, and long-term use. We report here a simple method to create thin (∼30 μm) conformal lubricating hydrogel coatings on catheters. The key to this method is a three-step process including shape-forming, gradient cross-linking, and swell-peeling (we label this method as SGS). First, we took advantage of the fast gelation of agar to form a hydrogel layer conformal to catheters; then, we performed a surface-bound UV cross-linking of acrylamide mixed in agar in open air, purposely allowing gradual oxygen inhibition of free radicals to generate a gradient of cross-linking density across the hydrogel layer; and finally, we caused the hydrogel to swell to let the non-cross-linked/loosely attached hydrogel fall off, leaving behind a surface-bound, thin, and mostly uniform hydrogel coating. This method also allowed easy incorporation of different polymerizable monomers to obtain multifunctionality. For example, incorporating an antifouling, zwitterionic moiety sulfobetaine in the hydrogel reduced both in vitro protein adsorption and in vivo foreign-body response in mice. The addition of a biocidal N-halamine monomer to the hydrogel coating deactivated both Staphylococcus aureus ( S. aureus) and Escherichia coli ( E. coli) O157:H7 within 30 min of contact and reduced biofilm formation by 90% compared to those of uncoated commercial catheters when challenged with S. aureus for 3 days. The lubricating, antibiofouling hydrogel coating may bring clinical benefits in the use of urinary and venous catheters as well as other types of medical devices.

A collection of 206 Staphylococcus spp. isolates was investigated for their ability to produce compounds exhibiting antistaphylococcal activity. This group included Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus xylosus strains recovered from bovine mastitis (n = 158) and human skin wounds and soft tissues infections (n = 48). Production of substances with antimicrobial activity was observed in six strains. Five of them were recovered from bovine mastitis, and one was isolated from the infected human skin wound. Three of the six antimicrobials produced by the different strains showed substantial loss of antimicrobial activity upon treatment with proteolytic enzymes, which suggests their peptidic structure. Additional studies have shown that one of the putative bacteriocins was efficiently secreted to the liquid medium, facilitating its large-scale production and isolation. The peptide produced by the M2B strain exhibited promising activity; however, against narrow spectrum of Staphylococcus spp. clinical and animal isolates. Growth inhibition was observed only in the case of 13 (including nine S. aureus, three S. xylosus and one S. epidermidis strains) out of 206 strains tested. Important advantage of the produced agent was its high thermal stability. Fifteen minutes of incubation at 90°C did not affect its antimicrobial potential. The highest efficiency of production of the agent was demonstrated in TSB medium after 24 hours at 37°C. The researches revealed that ability to production of bacteriocin among staphylococci is not very common. Only one (S. xylosus strain assigned as M2B) out of 206 strains tested produced satisfactory amounts of antistaphylococcal bacteriocin. In spite of that, we would encourage other researchers for investigation of their collections of Staphylococcus spp. isolates towards selection strains producing antimicrobial agents.

Microbial spoilage of fruit and vegetable juices represents an important threat to food quality and an area of concern in reducing food waste. Despite this, relatively little research is dedicated to microbial spoilage compared to other aspects of food microbiology. Establishing the incidence and impact of microbial spoilage in juice production would provide justification for future research. In this study, we present the findings from a survey of juice processor members of the U.S. based Juice Products Association and the European based International Fruit and Vegetable Juice Association (31.1% response rate). Respondents were asked a series of forced choice, Likert-type, and open response questions regarding microbial juice quality challenges and control measures regarding their facility. The vast majority of respondents (97.4%) indicated that spoilage mattered a lot or a great deal in brand protection. An additional 89.5% indicated that better control over microbial food spoilage would reduce waste and increase profits, with 57.9% indicating a lot or a great deal of impact, perhaps as a result of the frequency with which respondents indicated they discarded ingredients or product to protect quality. The most frequent disposition reportedly occurred on a weekly basis, with over half of respondents indicating discarding ingredients or product at least annually. Manufacturers reported a range of challenges, notably spoilage from Alicyclobacillus and heat resistant mold. This was accompanied by an identified need for associated sanitation and production control strategies. This work provides a basis for subsequent research exploring improved control strategies and detection methods used to reduce microbial spoilage of fruit and vegetable juices.

Novel processing technologies can be used to improve both the microbiological safety and quality of food products. The application of high pressure processing (HPP) in combination with dimethyl dicarbonate (DMDC) represents a promising alternative to classical thermal technologies. This research work was undertaken to investigate the combined effect of HPP and DMDC, which was aimed at reaching over 5-log reduction in the reference pathogens Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes inoculated in apple juice. Different strains of each species were tested. The pressure (ranging from 100 to 600 MPa), dwell time (from 26 to 194 s), and DMDC (from 116 to 250 mg/L) were tested based on a central composite rotatable design. The dwell time, in the studied range, did not have a significant effect (p > 0.1) on the pathogens´ reduction. All treatments achieved a greater than 5-log reduction for E. coli O157:H7 and L. monocytogenes. The reductions for S. enterica were also greater than 5-log for almost all tested combinations. The results for S. enterica suggested that it is more resistant to HPP and DMDC compared with E. coli O157:H7 and L. monocytogenes. The findings of this study showed that DMDC at low concentrations can be added to apple juice to reduce the parameters conventionally applied in HPP. The combined use of HPP and DMDC was highly effective under the conditions of this study.

Consumers are increasingly searching for preservative-free and “natural” food options. Confectionery products with low water activity (aw) are typically considered resistant to contaminati...

Consumption of spicy foods and hot sauces is currently a popular trend worldwide. Shelf-stable acidified sauces are commonly hot-filled to ensure commercial sterility, but cold-fill-hold processes might also be suitable if microbial safety and stability are ensured. For this study, model acidified hot pepper sauces were developed and characterized. The effects of sauce pH and of two different organic acids on the survival of Pichia manshurica and Lactobacillus curvatus isolated from contaminated commercial hot sauces and on pathogenic Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes were assessed. Full factorial designs with three levels for pH (3.2, 3.5, and 3.9) and two for organic acid (citric and acetic) were used to determine the effects of these factors and their interactions on the survival of the microorganisms. Commercially sterile sauces were independently inoculated and kept at ambient temperature. Microbial counts were determined at different sampling times, depending on the treatment evaluated. Sauces acidified to pH 3.2 with citric or acetic acid were inoculated with cocktails of five strains or serotypes of the three pertinent pathogens, and inactivation curves were determined. Trials were performed in triplicate. A greater than 5-log reduction of P. manshurica and L. curvatus was achieved in less than 6 h in sauces adjusted to pH 3.2 with acetic acid. Greater than 5-log reductions of pathogenic bacteria were achieved 0.5 h after inoculation in sauces acidified to pH 3.2 with acetic acid. In contrast, at least 48 h was required to guarantee the same inactivation for the most tolerant pathogen when citric acid was used. Thus, a cold-fill-hold process may be a suitable alternative for acidified hot pepper sauces. Based on survival of the microorganisms evaluated in this study, microbial safety and stability can be achieved by adjusting the pH to 3.2 or less by the addition of acetic acid. Universidad de Costa Rica/[735-B5-246]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro Nacional de Ciencia y Tecnología de Alimentos (CITA) UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Tecnología de Alimentos

High pressure processing (HPP) is a popular method of processing juices to retain “fresh” properties. However, heat and pressure resistant fungi, Byssochlamys spp. and Aspergillus spp., can survive processing and cause spoilage. The goal of this study was to evaluate the pressure and time necessary to cause a reduction of heat and pressure resistant spoilage fungi common in juice and determine the effect of water activity (0.94–1.0 aw) and pH (3.5–7.0) on HPP inactivation kinetics. The effect of sulfites and dimethyl dicarbonate (DMDC) was also assessed as a proof of concept to determine if either aided in fungal inactivation. Refrigerated storage up to 26 weeks after treatment was performed to assess fungal growth. Processing A. pseudoglaucus in pH 3.5 diluted apple juice concentrate (DAJC) at 600 MPa for 15 min at 5 °C was more effective than in pH 4.6, 7.0, or 4.6 with sulfites. Processing A. fischeri at pH 3.5 or 7.0 for 15 min at 600 MPa, 5 °C or at pH 4.6 for 1.5 min at 450 MPa resulted in a 1-log reduction. The addition of DMDC to pH 7.0 DAJC inoculated with A. fischeri and processed at 600 MPa for 15 min resulted in 1-log activation rather than a reduction. The addition of 8 ppm potassium metabisulfite at pH 4.6 had varying effects between species and did not significantly increase the shelf life. Sulfites aided in reducing A. pseudoglaucus but increased the activation of A. fischeri and P. niveus (B. nivea Westling). Processing at 600 MPa for 15 min at 5 °C resulted in the activation of P. niveus at pH 3.5, 4.6 and 7.0 DAJC at 0.94–1.0 aw. Generally, a greater reduction of all fungi tested was observed at 1.0 aw than at 0.94 aw. A 17–26 week storage period could be achieved, but only at refrigeration.

Quality and safety of fresh produce are important to public health and maintaining commerce between Mexico and USA. While preventive practices can reduce risks of contamination and are generally successful, the variable environment of the supply chain of fresh produce can be suitable for introduction or proliferation of pathogenic microorganisms. As routine surveillance of these pathogens is not practical, indicator microorganisms are used to assess the sanitary conditions of production and handling environments. An opportunity exists to use indicators on fresh produce to measure how handling and transport from field to market may affect microbial populations that contribute to their quality or safety. The objective was to quantify indicator microorganisms on tomatoes sampled along the supply chain during the harvest year, in order to observe the levels and changes of populations at different locations. Roma tomatoes (n=475) were taken from the same lots (n=28) at four locations of the postharvest supply chain over five months: at arrival to and departure from the packinghouse in Mexico, at the distribution center in Texas, and at retail in USA. Samples were analyzed individually for four microbial populations: aerobic plate count (APC), total coliforms (TC), generic Escherichia coli, and yeasts and molds (YM). APC population differed (p

A needs assessment survey was designed and administered to measure knowledge of and attitudes toward food safety impacts of nonthermal processing technologies of shellfish and produce industry personnel and extension educators. An online survey was sent via e-mail notification with the survey link through professional listserves. The survey evaluated background information, knowledge, attitude, and training needs. A variety of response formats was used. Knowledge/attitude responses were analyzed using descriptive statistics, 1-way ANOVA and t-tests using SPSS software and reported at P 0.9. There were no differences in attitudes and knowledge between the 2 industry groups. The total attitude score, based on a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree), of the produce and shellfish industry and educator respondents toward nonthermal processing technologies was 3.6 ± 0.4, 3.4 ± 0.5, and 3.6 ± 0.4, respectively. Respondent's slightly indifferent attitude may reflect low knowledge regarding the impact of nonthermal processing technologies on food safety and quality. Both groups indicated a desire for information and/or training. For both industry and educators, common preferred formats for outreach resources were printed materials, Internet/web-based materials, and PowerPoint. Educators identified barriers as equipment cost, lack of information, and lack of product validation. While the majority of the respondents were aware of nonthermal processing, they were not knowledgeable, indicating a need for education and outreach in nonthermal processing methods to both shellfish/produce industry and food safety educators.

Food spoilage has an enormous economic impact, and microbial food spoilage plays a significant role in food waste and loss; subsequently, an equally significant portion of undergraduate food microbiology instruction should be dedicated to spoilage microbiology. Here, we describe a set of undergraduate microbiology laboratory exercises that focus specifically on food spoilage which were taught in 2 lab periods as part of the undergraduate food microbiology lab curriculum at Cornell University. The lab was broken down into 3 exercises. Two exercises lead students to determine the likely source of contamination in a canned salsa through (exercise 1a) plating and observation of colony morphology and (exercise 1b) determination of the thermal resistance for those isolates. The final exercise (2) involved detection of the spoilage bacterium Alicyclobacillus in apple juice. Spoiled juice demonstrations were also prepared in this exercise for students to observe sensorial changes resulting from spoilage, emphasizing that spoilage is not always visually detectable. Students were able to successfully determine the source of contamination based on the results of their laboratory findings, which they used to make recommendations for production to reduce microbial food spoilage in the canned salsa product. Based on student answers to discussion questions provided following lab exercises, participants were able to (a) identify the significance of microbial spoilage and how spoilage is principally different from food safety, (b) describe varying sensorial changes associated with microbial spoilage, and (c) employ methods and analysis to evaluate sources and type of contamination. Downloadable handouts and stepwise instructions are available as supporting information.