Proteolytic Fungi Isolated from Decayed and Damaged Raw Tomatoes and Implications Associated with Changes in Pericarp pH Favorable for Survival and Growth of Foodborne Pathogens

Raw and minimally processed high-acid fruits and vegetables are considered to be at low or no risk for supporting growth of foodborne pathogens. The potential increase in the pH of tissues as a result of fungal growth, however, may enhance the potential for survival and growth. We examined 77 decayed and 138 damaged, raw, ripe tomatoes for the presence of yeasts and molds that produce proteolytic enzymes and other metabolites that can potentially increase the pH of pulp tissue. The pH of decayed and sound radial pericarp tissues (pulp) of decayed tomatoes ranged from 4.7 to 7.8 (mean = 6.2) and 4.3 to 5.8 (mean = 5.0), respectively, whereas the pH of damaged and sound pericarp of damaged tomatoes ranged from 4.2 to 7.8 (mean = 5.2) and 4.2 to 8.0 (mean = 4.9), respectively. The pH of sound pericarp of 8.5% of decayed tomatoes and 3.4% of damaged tomatoes, respectively, was >5.41. In contrast, the pH of 70% of the decayed tissue and 18% of the damaged tissue was >5.41. Fungal isolates (n = 371) recovered from decayed and damaged tomatoes on dichloran rose bengal chloramphenicol agar were examined for proteolytic activity on gelatin agar and standard methods caseinate agar. One hundred eight (29%) of the isolates exhibited proteolytic activity on one or both differential media; 96 (89%) were molds, and 12 (11%) were yeasts. The pH of both media increased at the edge of proteolytic fungal colonies. Growth of proteolytic isolates from decayed tomatoes on tomato juice agar (pH = 4.3) and on the surface of tomato juice (pH = 4.1) caused an increase in mean pH values at the colony/medium interface to 7.2 and 6.4, respectively. Results show that some fungi capable of infecting raw tomatoes, as well as the mycoflora incident on tomato surfaces, can increase the pH of pericarp and juice to levels favorable for growth of most foodborne pathogenic bacteria.

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Attraction of a Free-Living Nematode, Caenorhabditis elegans, to Foodborne Pathogenic Bacteria and Its Potential as a Vector of Salmonella Poona for Preharvest Contamination of Cantaloupe

Journal of Food Protection ◽

10.4315/0362-028x-66.11.1964 ◽

2003 ◽

Vol 66 (11) ◽

pp. 1964-1971 ◽

Cited By ~ 25

Author(s):

KRISHAUN N. CALDWELL ◽

GARY L. ANDERSON ◽

PHILLIP L. WILLIAMS ◽

LARRY R. BEUCHAT

Keyword(s):

Caenorhabditis Elegans ◽

Foodborne Pathogens ◽

Pathogenic Bacteria ◽

Fruits And Vegetables ◽

Test Model ◽

Human Pathogens ◽

Free Living ◽

Bacterial Colony ◽

C Elegans ◽

Time Required

Caenorhabditis elegans was studied to determine the potential role of free-living microbivorous nematodes as vectors for preharvest contamination of fruits and vegetables with foodborne pathogens. The propensity of C. elegans to be attracted to seven strains of Escherichia coli O157:H7, eight serotypes of Salmonella, six strains of Listeria monocytogenes, and cantaloupe juice was investigated. Twenty to 30 adult worms were placed on the surface of K agar midway between a 24-h bacterial colony and 10 μl of uninoculated tryptic soy broth (TSB) or cantaloupe juice positioned 1.5 cm apart. The numbers of nematodes that migrated to the colony, to the TSB, and to the cantaloupe juice within 5, 10, 15, and 20 min at 21°C were determined, and then the plates were incubated at 37°C for up to 7 days to determine the ability of C. elegans to survive and reproduce in bacterial colonies. The nematode was attracted to colonies of all test pathogens and survived and reproduced within colonies for up to 7 days. C. elegans was not attracted to cantaloupe juice. The potential of C. elegans to serve as a vector for the transport of Salmonella Poona to cantaloupe rinds was investigated. Adult worms that had been immersed in a suspension of Salmonella Poona were deposited 1 or 3 cm below the surface of soil on which a piece of cantaloupe rind was placed. The rind was analyzed for the presence of Salmonella Poona after 1, 3, 7, and 10 days at 21°C. The presence of Salmonella Poona was evident more quickly on rinds positioned on soil beneath which C. elegans inoculated with Salmonella Poona was initially deposited than on rinds positioned on soil beneath which Salmonella Poona alone was deposited. The time required to detect Salmonella Poona on rinds was longer when the rind was placed 3 cm above the inoculum than when the rind was placed 1 cm above the inoculum. Free-living nematodes may play a role in the preharvest dispersal of incidental human pathogens in soil to the surfaces of raw fruits and vegetables in contact with soil during development and maturation, as evidenced by the behavior of C. elegans as a test model.

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Effect of Storage Temperature on Survival and Growth of Foodborne Pathogens on Whole, Damaged, and Internally Inoculated Jalapeños (Capsicum annuum var. annuum)

Journal of Food Protection ◽

10.4315/0362-028x.jfp-11-304 ◽

2012 ◽

Vol 75 (2) ◽

pp. 382-388 ◽

Cited By ~ 7

Author(s):

KARLEIGH HUFF ◽

RENEE BOYER ◽

CYNTHIA DENBOW ◽

SEAN O'KEEFE ◽

ROBERT WILLIAMS

Keyword(s):

Foodborne Pathogens ◽

Pathogenic Bacteria ◽

Storage Temperature ◽

External Surface ◽

Storage Conditions ◽

Internal Cavity ◽

Growth And Survival ◽

E Coli ◽

Foodborne Pathogenic Bacteria ◽

Survival And Growth

There is a lack of general knowledge regarding the behavior of foodborne pathogenic bacteria associated with jalapeño peppers. The survival and growth behaviors of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica on the interior and exterior of jalapeño peppers were determined under different storage conditions. Jalapeños were inoculated with a five-strain cocktail of L. monocytogenes, E. coli O157:H7, or S. enterica on the intact external surface, injured external surface, or intact internal cavity of jalapeño peppers and held at 7 or 12°C for a period of 14 days. Populations of each pathogen were determined at 0, 1, 2, 5, 7 10, and 14 days throughout storage. The uninjured, intact external surface of jalapeño peppers did not support growth of the pathogens tested under both storage conditions, with the exception of L. monocytogenes at 12°C. Populations of E. coli and S. enterica declined on the external injured surface of peppers at 7°C, but populations of L. monocytogenes remained consistent throughout the length of storage. At 12°C, L. monocytogenes and S. enterica populations increased throughout storage, and E. coli populations remained unchanged on injured surfaces. The uninjured internal cavity of the jalapeño supported growth of all pathogens at 12°C. Overall, L. monocytogenes was the microorganism most capable of growth and survival in association with jalapeño peppers for the scenarios tested. Results emphasize the importance of jalapeño pepper quality and proper storage conditions in preventing or reducing pathogen survival and growth.

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Inhibitory Effect of Lactobacillus plantarum FL75 and Leuconostoc mesenteroides FL14 against Foodborne Pathogens in Artificially Contaminated Fermented Tomato Juices

BioMed Research International ◽

10.1155/2019/6937837 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Aïssé Bah ◽

Helena Albano ◽

Joana Bastos Barbosa ◽

Imene Fhoula ◽

Yosra Gharbi ◽

...

Keyword(s):

Organic Acids ◽

Lactobacillus Plantarum ◽

Foodborne Pathogens ◽

Pathogenic Bacteria ◽

Leuconostoc Mesenteroides ◽

Foodborne Pathogen ◽

Inhibitory Effect ◽

Hplc Method ◽

Tomato Juice ◽

High Survival

Tomatoes and tomato based-foods contain beneficial microorganisms and various organic acids that have important nutritional values for human. The objective of this study was to access the physiochemical properties of fermented tomatoes juices and to evaluate the competitiveness of lactic acid bacteria (LAB) against Listeria monocytogenes, Listeria innocua, and Salmonella spp., in artificially contaminated tomato juice. Microbial counting (LAB, fungi Salmonella spp., and Listeria spp.) was performed after fermentation and weekly during storage. Different organic acids (Lactic, succinic, and acetic) and ethanol were also monitored using HPLC method. Color parameters were also determined. The results showed an increase of lactic and acetic acid content, during fermentation and storage of juices inoculated with Lactobacillus plantarum and Leuconostoc mesenteroides at 25°C. Besides, citric acid and ethanol revealed higher content at the end of storage compared to that registered at 4°C. The pH from tomatoes juices decreased from an initial value of 4.5 to below 3.2. Alongside, foodborne pathogen population was significantly suppressed in tomatoes juices when the samples were coinoculated with LAB strains. Moreover, the inhibition of Salmonella species was faster compared to that of Listeria. After four weeks of storage at 4°C, Lb. plantarum and Lc. mesenteroides showed high survival rate, while pathogenic bacteria, yeasts, and molds cell numbers decreased drastically in all the contaminated vials. This work highlights the efficiency of Lb. plantarum and Lc. mesenteroides as potential starters for developing nutritious and safe fermented tomato juice products.

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Polyphenols as Antioxidants for Extending Food Shelf-Life and in the Prevention of Health Diseases: Encapsulation and Interfacial Phenomena

Biomedicines ◽

10.3390/biomedicines9121909 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1909

Author(s):

Marlene Costa ◽

Zerrin Sezgin-Bayindir ◽

Sonia Losada-Barreiro ◽

Fátima Paiva-Martins ◽

Luciano Saso ◽

...

Keyword(s):

Oxidative Stress ◽

Foodborne Pathogens ◽

Fruits And Vegetables ◽

Antimicrobial Properties ◽

Fungal Growth ◽

Delivery Systems ◽

Health Concern ◽

Therapeutic Effects ◽

Colloidal Systems ◽

Endogenous Antioxidant

Toxicity caused by the exposure to human-made chemicals and environmental conditions has become a major health concern because they may significantly increase the formation of reactive oxygen species (ROS), negatively affecting the endogenous antioxidant defense. Living systems have evolved complex antioxidant mechanisms to protect cells from oxidative conditions. Although oxidative stress contributes to various pathologies, the intake of molecules such as polyphenols, obtained from natural sources, may limit their effects because of their antioxidant and antimicrobial properties against lipid peroxidation and against a broad range of foodborne pathogens. Ingestion of polyphenol-rich foods, such as fruits and vegetables, help to reduce the harmful effects of ROS, but the use of supramolecular and nanomaterials as delivery systems has emerged as an efficient method to improve their pharmacological and therapeutic effects. Suitable exogenous polyphenolic antioxidants should be readily absorbed and delivered to sites where pathological oxidative damage may take place, for instance, intracellular locations. Many potential antioxidants have a poor bioavailability, but they can be encapsulated to improve their ideal solubility and permeability profile. Development of effective antioxidant strategies requires the creation of new nanoscale drug delivery systems to significantly reduce oxidative stress. In this review we provide an overview of the oxidative stress process, highlight some properties of ROS, and discuss the role of natural polyphenols as bioactives in controlling the overproduction of ROS and bacterial and fungal growth, paying special attention to their encapsulation in suitable delivery systems and to their location in colloidal systems where interfaces play a crucial role.

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

Foods ◽

10.3390/foods10050941 ◽

2021 ◽

Vol 10 (5) ◽

pp. 941

Author(s):

Panayiota Xylia ◽

George Botsaris ◽

Panagiotis Skandamis ◽

Nikolaos Tzortzakis

Keyword(s):

Shelf Life ◽

Foodborne Pathogens ◽

Carbon Dioxide Production ◽

Microbial Load ◽

Expiration Date ◽

Postharvest Management ◽

Minimally Processed Vegetables ◽

Yeasts And Molds ◽

Staphylococcus Spp ◽

Spoilage Microorganisms

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.

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The Use of Bacteriophages in the Poultry Industry

Animals ◽

10.3390/ani10050872 ◽

2020 ◽

Vol 10 (5) ◽

pp. 872 ◽

Cited By ~ 6

Author(s):

Katarzyna Żbikowska ◽

Monika Michalczuk ◽

Beata Dolka

Keyword(s):

Foodborne Pathogens ◽

Pathogenic Bacteria ◽

Bacterial Resistance ◽

Health And Safety ◽

Legal Framework ◽

Multidrug Resistant ◽

Poultry Production ◽

Salmonella Spp ◽

Food Contact Surfaces ◽

Public Health And Safety

The emergence of multidrug-resistant infections and antibiotic failures have raised concerns over human and veterinary medicine worldwide. Poultry production has had to confront the problems of an alarming increase in bacterial resistance, including zoonotic pathogens. According to the European Food Safety Authority (EFSA), campylobacteriosis and salmonellosis have been the most frequently reported human foodborne diseases linked to poultry. This situation has strongly stimulated a renewal of scientists’ interest in bacteriophages (phages) since the beginning of the 21st century. Bacteriophages are the viruses of bacteria. They are abundant in nature, and accompany bacteria in each environment they colonize, including human microbiota. In this review, we focused on the use of bacteriophages as therapeutic agents to treat infections and reduce counts of pathogenic bacteria in poultry, as biocontrol agents to eliminate foodborne pathogens on/in food, and also as disinfectants to reduce contamination on food-contact surfaces or poultry carcasses in industrial conditions. Most of the phage-based products are targeted against the main foodborne pathogens, such as Campylobacter jejuni, Salmonella spp., Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, and Clostridium perfringens. Phages are currently addressed at all stages of the poultry production "from farm to fork", however, their implementation into live birds and food products still provokes discussions especially in the context of the current legal framework, limitations, as well as public health and safety.

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Transfer of Salmonella enterica Serovar Typhimurium from Beef to Tomato through Kitchen Equipment and the Efficacy of Intermediate Decontamination Procedures

Journal of Food Protection ◽

10.4315/0362-028x.jfp-15-531 ◽

2016 ◽

Vol 79 (7) ◽

pp. 1252-1258 ◽

Cited By ~ 6

Author(s):

E. GKANA ◽

A. LIANOU ◽

G.-J. E. NYCHAS

Keyword(s):

Foodborne Pathogens ◽

Salmonella Enterica ◽

Fruits And Vegetables ◽

Salmonella Enterica Serovar Typhimurium ◽

Tap Water ◽

Pathogenic Microorganisms ◽

Cross Contamination ◽

Raw Meat ◽

Serovar Typhimurium ◽

Cutting Boards

ABSTRACT It is well established that a high percentage of foodborne illness is caused by failure of consumers to prepare food in a hygienic manner. Indeed, a common practice in households is to use the same kitchen equipment for both raw meat and fresh produce. Such a practice may lead to cross-contamination of fruits and vegetables, which are mainly consumed without further processing, with pathogenic microorganisms originating from raw meat. The present study was performed to examine the transfer of the pathogenic bacterium Salmonella enterica serovar Typhimurium from inoculated beef fillets to tomatoes via contact with high-density polyethylene (PE), stainless steel (SS), and wooden (WD) surfaces and through cutting with SS knives. Furthermore, the following decontamination procedures were applied: (i) rinsing with tap water, (ii) scrubbing with tap water and liquid dish detergent, and (iii) using a commercial antibacterial spray. When surfaces and knives that came into contact with contaminated beef fillets were not cleaned prior to handling tomatoes, the lowest level of pathogen transfer to tomatoes was observed through PE surfaces. All of the decontamination procedures applied were more effective on knives than on surfaces, while among the surface materials tested, WD surfaces were the most difficult to decontaminate, followed by PE and SS surfaces. Mechanical cleaning with tap water and detergent was more efficient in decontaminating WD surfaces than using commercial disinfectant spray, followed by rinsing only with water. Specifically, reductions of 2.07 and 1.09 log CFU/cm2 were achieved by washing the WD surfaces with water and detergent and spraying the surfaces with an antibacterial product, respectively. Although the pathogen's populations on SS and PE surfaces, as well as on tomatoes, after both aforementioned treatments were under the detection limit, the surfaces were all positive after enrichment, and thus, the potential risk of cross-contamination cannot be overlooked. As demonstrated by the results of this study, washing or disinfection of kitchen equipment may not be sufficient to avoid cross-contamination of ready-to-eat foods with foodborne pathogens, depending on the decontamination treatment applied and the material of the surfaces treated. Therefore, separate cutting boards and knives should be used for processing raw meat and preparing ready-to-eat foods in order to enhance food safety.

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Insects as vectors of foodborne pathogenic bacteria

Terrestrial Arthropod Reviews ◽

10.1163/187498311x543989 ◽

2011 ◽

Vol 4 (1) ◽

pp. 5-16 ◽

Cited By ~ 21

Author(s):

Jeffrey Blazar ◽

Marc Allard ◽

E. Kurt Lienau

Keyword(s):

Food Safety ◽

Foodborne Pathogens ◽

Pathogenic Bacteria ◽

Current Knowledge ◽

Disease Outbreaks ◽

House Fly ◽

American Cockroach ◽

Health Concern ◽

Foodborne Disease ◽

Salmonella Spp

AbstractFood safety is an important consideration worldwide. To maintain and improve our current knowledge of foodborne disease outbreaks, we must understand some of the more imminent issues related to food safety. A variety of agents are responsible for transmitting the estimated 76 million cases of illnesses caused by foodborne pathogens every year. This review explores why insects pose a serious health concern, in terms of worldwide food safety initiatives, by looking at evidence in published <abs>Food safety is an important consideration worldwide. To maintain and improve our current knowledge of foodborne disease outbreaks, we must understand some of the more imminent issues related to food safety. A variety of agents are responsible for transmitting the estimated 76 million cases of illnesses caused by foodborne pathogens every year. This review explores why insects pose a serious health concern, in terms of worldwide food safety initiatives, by looking at evidence in published literature. We highlight at least eleven different species of insects, including the lesser mealworm, Alphitobius diaperinus (Panzer); secondary screwworm, Cochliomyia macellaria (Fabricius); synanthropic flies [flesh fly, Sarcophaga carnaria (L.); house fly, Musca domestica (L.); fruit fly, Drosophila melanogaster (Meigen); and stable fly, Stomoxys calcitrans (L.)], American cockroach, Periplaneta americana (L.); German cockroach, Blatella germanica (L.); Oriental cockroach, Blatta orientalis (L.); Pacific beetle cockroach, Diploptera punctata (Eschscholtz); and Speckled feeder cockroach, Nauphoeta cinerea (Olivier), which act as vectors for Salmonella spp. or Escherichia coli and illustrate how these insects are successful vectors of foodborne disease outbreaks. We propose that insects be considered as one of the latest issues in food safety initiatives. Not only are some insects extremely important contributors to diseases, but now we suggest that more research into insects as potential carriers of E. coli and Salmonella spp., and therefore as contributing to foodborne disease outbreaks, is granted.

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Survival and Growth of Foodborne Pathogens on Commercial Dishsponges/cloths and Inhibitory Effects of Sanitizers

Food Science and Technology Research ◽

10.3136/fstr.18.437 ◽

2012 ◽

Vol 18 (3) ◽

pp. 437-443 ◽

Cited By ~ 2

Author(s):

Young-Min BAE ◽

Seung-Hee LEE ◽

Jin-Hee YOO ◽

Sun-Young LEE

Keyword(s):

Foodborne Pathogens ◽

Inhibitory Effects ◽

Survival And Growth

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Evaluation of Gaseous Chlorine Dioxide as a Sanitizer for Killing Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, and Yeasts and Molds on Fresh and Fresh-Cut Produce

Journal of Food Protection ◽

10.4315/0362-028x-68.6.1176 ◽

2005 ◽

Vol 68 (6) ◽

pp. 1176-1187 ◽

Cited By ~ 112

Author(s):

KAYE V. SY ◽

MELINDA B. MURRAY ◽

M. DAVID HARRISON ◽

LARRY R. BEUCHAT

Keyword(s):

Escherichia Coli ◽

Listeria Monocytogenes ◽

Chlorine Dioxide ◽

Foodborne Pathogens ◽

Escherichia Coli O157 ◽

Gaseous Chlorine Dioxide ◽

Sensory Qualities ◽

A Cell ◽

Fresh Cut ◽

Yeasts And Molds

Gaseous chlorine dioxide (ClO2) was evaluated for effectiveness in killing Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on fresh-cut lettuce, cabbage, and carrot and Salmonella, yeasts, and molds on apples, peaches, tomatoes, and onions. Inoculum (100 μl, ca. 6.8 log CFU) containing five serotypes of Salmonella enterica, five strains of E. coli O157:H7, or five strains of L. monocytogenes was deposited on the skin and cut surfaces of fresh-cut vegetables, dried for 30 min at 22°C, held for 20 h at 4°C, and then incubated for 30 min at 22°C before treatment. The skin surfaces of apples, peaches, tomatoes, and onions were inoculated with 100 μl of a cell suspension (ca. 8.0 log CFU) containing five serotypes of Salmonella, and inoculated produce was allowed to dry for 20 to 22 h at 22°C before treatment. Treatment with ClO2 at 4.1 mg/liter significantly (α = 0.05) reduced the population of foodborne pathogens on all produce. Reductions resulting from this treatment were 3.13 to 4.42 log CFU/g for fresh-cut cabbage, 5.15 to 5.88 log CFU/g for fresh-cut carrots, 1.53 to 1.58 log CFU/g for fresh-cut lettuce, 4.21 log CFU per apple, 4.33 log CFU per tomato, 1.94 log CFU per onion, and 3.23 log CFU per peach. The highest reductions in yeast and mold populations resulting from the same treatment were 1.68 log CFU per apple and 2.65 log CFU per peach. Populations of yeasts and molds on tomatoes and onions were not significantly reduced by treatment with 4.1 mg/liter ClO2. Substantial reductions in populations of pathogens on apples, tomatoes, and onions but not peaches or fresh-cut cabbage, carrot, and lettuce were achieved by treatment with gaseous ClO2 without markedly adverse effects on sensory qualities.

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