Category Archives: pathogenic

Research – Number of foodborne illnesses associated with outbreaks in tomatoes decreased since 2001

Posted on July 21, 2019 by | Leave a comment

FreshPlaza

About 48 million episodes of foodborne illness and 3,000 deaths occur per year in the United States. The most common foodborne pathogens cause an estimated annual burden of $14 billion to $36 billion. Produce has been implicated in 46 percent of foodborne illness outbreaks. Tomatoes have been the source of a number of foodborne illness outbreaks since 1998, but the annual number of foodborne illnesses associated with outbreaks in tomatoes has generally decreased since their high of nearly 900 in 2001. Ten outbreaks have caused more than 100 illnesses, while 2 were associated with deaths of individuals. In 2005 and 2006, multistate outbreaks of salmonella in tomatoes sickened 487 individuals.

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Posted in food bourne outbreak, food contamination, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, food recall, Food Safety, Food Testing, foodborne outbreak, foodbourne outbreak, outbreak, Pathogen, pathogenic, Uncategorized

Research – Antibacterial Effects of Phytic Acid against Foodborne Pathogens and Investigation of Its Mode of Action

Posted on May 6, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

This study investigated the antimicrobial mechanism of phytic acid (PA) and its antibacterial effects in combination with ethanol. The MIC of PA on Escherichia coli ATCC 11229, Staphylococcus aureus ATCC 6538P, Bacillus subtilis ATCC 6633, and Salmonella Typhimurium CICC 27483 were 0.24, 0.20, 0.26, and 0.28% (w/w), respectively. E. coli ATCC 11229 and S. aureus ATCC 6538P were selected to investigate the mechanism of PA by analyzing its effects at 1/2MIC and at MIC on the cell morphology, intracellular ATP, and cell membrane integrity. Environmental scanning electron microscope images revealed that PA was able to change the cell morphology and disrupt the intercellular adhesion. PA retarded bacterial growth and caused cell membrane dysfunction, which was accompanied by decreased intracellular ATP concentrations. Flow cytometry analysis further revealed that almost all the bacterial cells were damaged after treatment with PA at its MIC for 2 h. Moreover, PA has a synergistic antimicrobial ability when used in combination with ethanol. These results suggested that PA is effective in inhibiting growth of foodborne pathogens mainly by the mechanism of cell membrane damage and to provide a theoretical basis for the development of natural antimicrobial agents in the food industry.

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Posted in Bacillus Subtilis, E.coli, Food Micro Blog, Food Microbiology Blog, Food Pathogen, Food Technology, microbial contamination, Microbiology, Pathogen, pathogenic, Salmonella, Staphylococcus aureus, Technology, Uncategorized

Research – Growth of Salmonella and Other Foodborne Pathogens on Inoculated Inshell Pistachios during Simulated Delays between Hulling and Drying

Posted on May 4, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

During harvest, pistachios are hulled, separated in water into floater and sinker streams (in large part on the basis of nut density), and then dried before storage. Higher prevalence and levels of Salmonella were previously observed in floater pistachios, but contributing factors are unclear. To examine the behavior of pathogens on hulled pistachios during simulated drying delays, floater and sinker pistachios collected from commercial processors were inoculated at 1 or 3 log CFU/g with cocktails of Salmonella and in some cases Escherichia coli O157:H7 or Listeria monocytogenes and incubated for up to 30 h at 37°C and 90% relative humidity. Populations were measured by plating onto tryptic soy agar and appropriate selective agars. In most cases, no significant growth (P > 0.05) of Salmonella was observed in the first 3 h after inoculation in hulled floaters and sinkers. Growth of Salmonella was greater on floater pistachios than on corresponding sinkers and on floater pistachios with ≥25% hull adhering to the shell surface than on corresponding floaters with <25% adhering hull. Maximum Salmonella populations (2 to 7 log CFU/g) were ∼2-log higher on floaters than on corresponding sinkers. The growth of E. coliO157:H7 and Salmonella on hulled pistachios was similar, but a longer lag time (approximately 11 h) and significantly lower maximum populations (4 versus 5 to 6 log CFU/g; P < 0.05) were predicted for L. monocytogenes. Significant growth of pathogens on hulled pistachios is possible when delays between hulling and drying are longer than 3 h, and pathogen growth is enhanced in the presence of adhering hull material.

HIGHLIGHTS

  • Foodborne pathogens multiplied on undried inshell pistachios.

  • Pathogen growth was greater when hull material was present.

  • Drying delays of >3 h led to significant increases in pathogen populations.

  • Managing drying delays will reduce the risk for growth of foodborne pathogens.

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Posted in E.coli, E.coli O157, E.coli O157:H7, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Technology, Food Testing, Pathogen, pathogenic, Salmonella, Uncategorized

Research – Differences Among Incidence Rates of Invasive Listeriosis in the U.S. FoodNet Population by Age, Sex, Race/Ethnicity, and Pregnancy Status, 2008–2016

Posted on February 14, 2019 by | Leave a comment

Mary Ann Leibert listeria

Listeria monocytogenes is a foodborne pathogen that disproportionally affects pregnant females, older adults, and immunocompromised individuals. Using U.S. Foodborne Diseases Active Surveillance Network (FoodNet) surveillance data, we examined listeriosis incidence rates and rate ratios (RRs) by age, sex, race/ethnicity, and pregnancy status across three periods from 2008 to 2016, as recent incidence trends in U.S. subgroups had not been evaluated. The invasive listeriosis annual incidence rate per 100,000 for 2008–2016 was 0.28 cases among the general population (excluding pregnant females), and 3.73 cases among pregnant females. For adults ≥70 years, the annual incidence rate per 100,000 was 1.33 cases. No significant change in estimated listeriosis incidence was found over the 2008–2016 period, except for a small, but significantly lower pregnancy-associated rate in 2011–2013 when compared with 2008–2010. Among the nonpregnancy-associated cases, RRs increased with age from 0.43 (95% confidence interval: 0.25–0.73) for 0- to 14-year olds to 44.9 (33.5–60.0) for ≥85-year olds, compared with 15- to 44-year olds. Males had an incidence of 1.28 (1.12–1.45) times that of females. Compared with non-Hispanic whites, the incidence was 1.57 (1.18–1.20) times higher among non-Hispanic Asians, 1.49 (1.22–1.83) among non-Hispanic blacks, and 1.73 (1.15–2.62) among Hispanics. Among females of childbearing age, non-Hispanic Asian females had 2.72 (1.51–4.89) and Hispanic females 3.13 (2.12–4.89) times higher incidence than non-Hispanic whites. We observed a higher percentage of deaths among older patient groups compared with 15- to 44-year olds. This study is the first characterizing higher RRs for listeriosis in the United States among non-Hispanic blacks and Asians compared with non-Hispanic whites. This information for public health risk managers may spur further research to understand if differences in listeriosis rates relate to differences in consumption patterns of foods with higher contamination levels, food handling practices, comorbidities, immunodeficiencies, health care access, or other factors.

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Posted in food contamination, food death, Food Hygiene, Food Illness, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Testing, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Uncategorized

Research – PopPUNK advances speed of bacterial pathogen surveillance

Posted on January 29, 2019 by | Leave a comment

Science Daily

In a study published today in Genome Research, researchers developed PopPUNK (Population Partitioning Using Nucleotide K-mers), a computational tool for analyzing tens of thousands of bacterial genomes in a single run, up to 200-fold faster than previous methods. Researchers envision PopPUNK will expedite the identification of bacterial strains as the scale of bacterial genomes being sequenced increases and, importantly, allow public health agencies to quickly identify outbreak strains that pose a public health risk.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Technology, Food Testing, Pathogen, pathogenic, Uncategorized, Whole Genomic Sequencing

Research – How to kill pathogens on seafood

Posted on December 19, 2018 by | Leave a comment

Food Processing

Controlled release antimicrobial film makes seafood safer.

Seafood may be contaminated with bacterial pathogens, such as Vibrio and Salmonella, which can survive long-term freezing conditions. Vibrio naturally occur in marine environments and Salmonella can contaminate seafood during production or processing and both are concerns for the seafood industry.

However, a solution may be at hand. A biodegradable, edible film made with plant starch and antimicrobial compounds may control the growth of foodborne pathogens on seafood, according to a group of international researchers.

Catherine Cutter, professor of food science, Penn State, explained, “We have the ability to develop a film with antimicrobial activity that can kill foodborne pathogens on food surfaces. Given the recent outbreaks that we have seen with a number of food products, coming up with something that can be used by the industry to kill microorganisms on the surfaces of food is a noble area of research to investigate.

“Vibrio and Salmonella are somewhat susceptible to freezing,” Cutter said. “So, if you treat bacterial cells with antimicrobials and then freeze them, the approach can be more lethal.”

Freezing does not kill bacteria. However, when freezing food, ice crystals can form from the water in food. The ice crystals, Cutter said, can act like “daggers” and pierce the bacterial cell wall, causing damage to the cell.

Researchers used a blend of thermoplastic starch, a biodegradable polymer made from tapioca powder and a gelatin coating containing antimicrobials known as Nisin Z and lauric arginate (LAE).

 

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, microbial contamination, Pathogen, pathogenic, Salmonella, Uncategorized, Vibrio, Vibrio cholera, Vibrio parahaemolyticus, Vibrio vulnificans, water microbiology

Research – Innate antimicrobial immunity in the skin: A protective barrier against bacteria, viruses, and fungi

Posted on December 11, 2018 by | Leave a comment

PLOS One

The epidermis, the outermost layer of the skin, is a physical barrier against pathogens. However, breach of the skin barrier through wounding introduces a myriad of microbes to the site of injury. Upon disturbance of the epidermal barrier, the innate immune system and its effectors play a key role in protecting humans against cutaneous and systemic infection [1]. Major constituents of the innate immune system include phagocytic cells, such as macrophages, neutrophils, and dendritic cells, as well as innate leukocytes, such as natural killer (NK) cells, mast cells, basophils, and eosinophils. In addition, epidermal keratinocytes act as active innate immune cells. In response to sensing pathogen-associated molecular patterns (PAMPs) expressed by microbes and host danger molecules, innate immune receptors present on keratinocytes become activated, causing release of inflammatory cytokines and host antimicrobial molecules [2, 3].

Recognition of pathogens

The first step of any immune response is recognition of potential pathogens. Germline-encoded pattern recognition receptors (PRRs) recognize PAMPs present on microbes and damaged-associated molecular patterns (DAMPs) on host cells (Fig 1) [4]. The four primary groups of human PRRs are toll-like receptors (TLRs), nucleotide-binding oligomerization domain-like receptors (NLRs), retinoic acid-inducible gene 1 (RIG-I)-like helicase receptors (RLRs) and c-type lectin receptors (CLRs) [4]. Signaling through PRRs has long been known to be essential for activation of the innate immune response. For example, stimulation of TLR2 increases the immune response to pathogens and helps rescue the inflammatory response of immunosuppressed patients with sepsis [5]. Although PRRs are not as specific as immune effectors of the adaptive immune system, different PRRs have evolved to recognize different molecular patterns [6]. For example, TLR2, TLR6, and nucleotide-binding oligomerization domain-containing protein 2 (NOD2) appear to play an important role in host defense against staphylococcal aureus, whereas TLRs 2, 3, 7, 8, and 9 have been found to be activated by many viruses, including members of the herpesviruses, papillomaviruses, and poxviruses [7, 8]. CLRs and TLRs 2, 4, and 9 are thought to be primary receptors involved in recognition of fungal pathogens such as Candida albicans, and there are reports of specific PRR deficiencies in patients with chronic mucocutaneous infections [9, 10].

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Posted in Bacteria, Food Virus, Pathogen, pathogenic, Uncategorized, Virus

Research – Migratory birds along the Mediterranean – Black Sea Flyway as carriers of zoonotic pathogens

Posted on November 10, 2018 by | Leave a comment

NRC

At the crossroad between Europe, Asia, and Africa, Bulgaria is part of the Mediterranean – Black Sea Flyway (MBSF) used by millions of migratory birds. In this study, bird species migrating through Bulgaria were investigated as carriers of zoonotic pathogens. In total, 706 birds belonging to 46 species were checked for the presence of various bacterial pathogens (Campylobacter, Yersinia, Salmonella, Listeria, Escherichia coli, Staphylococcus aureus, Francisella tularensis, Coxiella burnetii, Borrelia burgdorferi, and Brucella spp.). From 673 birds we investigated fecal samples, from the remaining 33, blood samples. We detected Campylobacter 16S rDNA gene in 1.3% of birds, but none were of pathogenic Campylobacter jejuni and Campylobacter coli species. Escherichia coli 16S rDNA gene was found in 8.8% of the birds. Out of 34 birds that transported Yersinia enterocolitica strains (5.05%), only 1 carried a pathogenic isolate. Three birds (0.4%) were carriers of nonpathogenic Salmonella strains. Four avian samples (0.6%) were positive for Listeria monocytogenes and 1 (0.15%) was positive for Brucella spp. None of the birds tested carried the tick-borne pathogens C. burnetii or B. burgdorferi sensu lato. Antibiotic-resistant strains were detected, suggesting that migratory birds could be reservoirs and spreaders of bacterial pathogens as well as antibiotic resistance genes.

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Posted in Campylobacter, E.coli, Food Pathogen, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Salmonella, Staphylococcus aureus, Uncategorized, Yersinia

Research – Composting To Inactivate Foodborne Pathogens for Crop Soil Application: A Review

Posted on October 27, 2018 by | Leave a comment

Journal of Food Protection

Compost is organic material that has been degraded into a nutrient-stabilized humus-like substance through intense microbial activity, which can provide essential plant nutrients (nitrogen, phosphorus) to aid in the growth of fruits and vegetables. Compost can be generated from animal waste feedstocks; these can contain human pathogens, which can be inactivated through the heat and microbial competition promoted during the composting process. Outbreaks of infections caused by bacterial pathogens such as Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on fruit and vegetable commodities consumed raw emphasize the importance of minimizing the risk of pathogenic contamination on produce commodities. This review article investigates factors that affect the reduction and survival of bacterial foodborne pathogens during the composting process. Interactions with indigenous microorganisms, carbon:nitrogen ratios, and temperature changes influence pathogen survival, growth, and persistence in finished compost. Understanding the mechanisms of pathogen survival during the composting process and mechanisms that reduce pathogen populations can minimize the risk of pathogen contamination in the cultivation of fruits and vegetables.

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Posted in E.coli O157, E.coli O157:H7, food contamination, Food Hygiene, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Testing, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Salmonella, Uncategorized

Research – Ruminant and chicken: important sources of Campylobacteriosis in France

Posted on June 22, 2018 by | Leave a comment

Poultry Med

Campylobacter spp. are regarded as the most common foodborne bacterial zoonosis in Europe, despite potential underestimation due to underreporting of cases. In France, C. jejuni is responsible for nearly 80% of human infections while C. coli accounts for around 15%. The economic burden of campylobacteriosis has been estimated to 2.4 billion euros annually in Europe, with estimates of £50 million in 2008–2009 in the United Kingdom and 82 million euros in the Netherlands in 2011.Pathogen source attribution studies are a useful tool for identifying reservoirs of human infection. Based on Multilocus Sequence Typing (MLST) data, such studies have identified chicken as a major source of C. jejuni human infection. The use of whole genome sequence-based typing methods offers potential to improve the precision of attribution beyond that which is possible from 7 MLST loci. Using published data and 156 novel C. jejuni genomes sequenced in this study, the researchers performed probabilistic host source attribution of clinical C. jejuni isolates from France using three types of genotype data: comparative genomic fingerprints; MLST genes; 15 host segregating genes previously identified by whole genome sequencing. Consistent with previous studies, chicken was an important source of campylobacteriosis in France (31–63% of clinical isolates assigned). There was also evidence that ruminants are a source (22–55% of clinical isolates assigned), suggesting that further investigation of potential transmission routes from ruminants to human would be useful.

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Posted in Campylobacter, food contamination, Food Hygiene, Food Inspections, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Testing, Pathogen, pathogenic, Research, Uncategorized