Category Archives: Salmonella

Research – Ultrasound treatment combined with fumaric acid for inactivating food-borne pathogens in apple juice and its mechanisms

Posted on August 16, 2019 by | Leave a comment

Science Direct

Highlights

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The combination of Ultrasound (US) and fumaric acid (FA) showed a synergistic bactericidal effect in apple juice.

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US-FA combined treatment of apple juice did not affect quality.

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Cell membrane damage was the main mechanism of US-FA synergistic lethal effect.

Abstract

The purpose of this study was to evaluate the synergistic bactericidal efficacy of combining ultrasound (US) and fumaric acid (FA) treatment against Escherichia coliO157:H7, Salmonella Typhimurium, and Listeria monocytogenes in apple juice and to identify the synergistic bactericidal mechanisms. Additionally, the effect of combination treatment on juice quality was determined by measuring the changes in color, pH, non-enzymatic browning index, and total phenolic content. A mixed cocktail of the three pathogens was inoculated into apple juice, followed by treatment with US (40 kHz) alone, FA (0.05, 0.1, and 0.15%) alone, and a combination of US and FA for 1, 2, 3, 4, and 5 min. Combined US and 0.15% FA treatment for 5 min achieved 5.67, 6.35, and 3.47 log reductions in E. coli O157:H7, S.Typhimurium, and L. monocytogenes, respectively, with the 1.55, 2.37, and 0.57 log CFU reductions attributed to the synergistic effect. Although the pH value slightly decreased as FA increased, there were no significant (P > 0.05) differences in color values, browning indices, and phenolic content between untreated and treated samples. To identify the mechanism of this synergistic bactericidal action, membrane integrity, malfunctions in the membrane efflux pump, and intracellular enzyme activity were measured. The analyses confirmed that damage to the cell envelope (membrane integrity and efflux pump) was strongly related to the synergistic microbial inactivation. These results suggest that simultaneous application of US treatment and FA is a novel method for ensuring the microbial safety of apple juice.

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Posted in E.coli, E.coli O157, E.coli O157:H7, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbiology, Salmonella, Technology, Uncategorized

Research – A Bacteriophage Cocktail Eliminates Salmonella Typhimurium from the Human Colonic Microbiome while Preserving Cytokine Signaling and Preventing Attachment to and Invasion of Human Cells by Salmonella In Vitro

Posted on August 14, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

Nontyphoidal Salmonella strains continue to be a major cause of foodborne illness globally. One intriguing approach to reducing the risk of salmonellosis is the direct ingestion of phages targeting Salmonella to enhance natural gut resilience and provide protection during foodborne disease outbreaks. We evaluated the ability of a prophylactically administered bacteriophage cocktail, the foodborne outbreak pill (FOP) targeting Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella, to resolve a Salmonella infection in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME), a simulated gut platform populated by the human intestinal microbiome of healthy donors. The FOP preparation eliminated Salmonella enterica serovar Typhimurium from the colon compartment of the SHIME platform but health-associated metabolites, such as short-chain fatty acids and lactate, remained stable or increased in a donor-dependent manner. In studies of human intestinal cells, pretreatment of Salmonella Typhimurium with the FOP cocktail preserved lipopolysaccharide-stimulated signaling in a Caco-2–THP-1 Transwell system and prevented destruction of the Caco-2 monolayer by Salmonella. Adhesion and invasion of intestinal epithelial cells by Salmonella—a critical factor in Salmonella pathogenesis—was blunted when the bacteria were incubated with the FOP preparation before addition to the monolayer. The FOP phage cocktail was effective for (i) eliminating Salmonella from a simulated human gut without disturbing the indigenous microbiota and (ii) reducing the risk of invasion by Salmonella into the intestinal epithelia. These results suggest that the FOP preparation may be of value for reducing the risk of salmonellosis in humans, e.g., during foodborne disease outbreaks.

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Posted in food bourne outbreak, food contamination, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Technology, Food Testing, foodborne disease, Foodborne Illness, Salmonella, Uncategorized

Research – Effect of Food Structure, Water Activity, and Long-Term Storage on X-Ray Irradiation for Inactivating Salmonella Enteritidis PT30 in Low-Moisture Foods

Posted on August 11, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

Recent outbreaks and recalls of low-moisture foods contaminated with Salmonella have been recognized as a major public health risk that demands the development of new Salmonella mitigation strategies and technologies. This study aimed to assess the efficacy of X-ray irradiation for inactivating Salmonella on or in almonds (kernels, meal, butter), dates (whole fruit, paste), and wheat (kernels, flour) at various water activities (aw) and storage periods. The raw materials were inoculated with Salmonella Enteritidis PT30, conditioned to 0.25, 0.45, and 0.65 aw in a humidity-controlled chamber, processed to various fabricated products, and reconditioned to the desired aw before treatment. In a storage study, inoculated almond kernels were stored in sealed tin cans for 7, 15, 27, and 103 weeks, irradiated with X ray (0.5 to 11 kGy, targeting up to a ∼2.5-log reduction) at the end of each storage period, and plated for Salmonella survivors to determine the efficacy of irradiation in terms of D10-value (dose required to reduce 90% of the population). Salmonella was least resistant (D10-value = 0.378 kGy) on the surface of almond kernels at 0.25 aw and most resistant (D10-value = 2.34 kGy) on the surface of dates at 0.45 aw. The Salmonella D10-value was 61% lower in date paste than on whole date fruit. Storage of almonds generally had no effect on the irradiation resistance of Salmonella over 103 weeks. Overall, these results indicate that product structure (whole, meals, powder, or paste), water activity (0.25 to 0.65 aw), and storage period (0 to 103 weeks) should be considered when determining the efficacy of X-ray irradiation for inactivating Salmonella in various low-water-activity foods.

HIGHLIGHTS

  • Salmonella resistance to X ray was significantly different on almonds, wheat, and dates.

  • The structural changes of almonds significantly impacted Salmonella resistance to X ray.

  • Water activity affected the efficacy of X ray for inactivating Salmonella in low-moisture foods.

  • Storing almonds up to 103 weeks had no effect on the X-ray resistance of Salmonella.

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Posted in Food Hygiene, Food Micro Blog, Food Microbiology Blog, Food Safety, Food Technology, Food Testing, microbial contamination, Microbiology, Salmonella, Uncategorized

Research -Slow growth determines nonheritable antibiotic resistance in Salmonella enterica

Posted on August 8, 2019 by | Leave a comment

Science Mag

kswfoodworld Salmonella

Image CDC

Slow growth for bacterial persistence

Even bacteria that do not carry mutations or genes that confer resistance to specific antibiotics can survive antibiotic treatment, a phenomenon known as persistence (see the Focus by Kaldalu and Tenson). Several models have been proposed to account for bacterial persistence, including the activation of toxins in toxin-antitoxin modules, the production of the alarmone guanosine (penta) tetraphosphate [(p)ppGpp], and a reduction in intracellular adenosine triphosphate (ATP) abundance. Pontes and Groisman demonstrated that Salmonella exhibited persistence even in the absence of toxin-antitoxin modules or (p)ppGpp production and under conditions that increased intracellular ATP. These and additional findings show that slow growth alone is sufficient for persistence and may contribute to the difficulty in treating some bacterial infections.

Abstract

Bacteria can withstand killing by bactericidal antibiotics through phenotypic changes mediated by their preexisting genetic repertoire. These changes can be exhibited transiently by a large fraction of the bacterial population, giving rise to tolerance, or displayed by a small subpopulation, giving rise to persistence. Apart from undermining the use of antibiotics, tolerant and persistent bacteria foster the emergence of antibiotic-resistant mutants. Persister formation has been attributed to alterations in the abundance of particular proteins, metabolites, and signaling molecules, including toxin-antitoxin modules, adenosine triphosphate, and guanosine (penta) tetraphosphate, respectively. Here, we report that persistent bacteria form as a result of slow growth alone, despite opposite changes in the abundance of such proteins, metabolites, and signaling molecules. Our findings argue that transitory disturbances to core activities, which are often linked to cell growth, promote a persister state regardless of the underlying physiological process responsible for the change in growth.

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Posted in Antibiotic Resistance, antimicrobial resistance, Antimicrobials, Food Micro Blog, Food Microbiology Blog, microbial contamination, Microbiology, Salmonella, Uncategorized

Research – Detection of Virulence Plasmid–Encoded Genes in Salmonella Typhimurium and Salmonella Kentucky Isolates Recovered from Commercially Processed Chicken Carcasses

Posted on August 7, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

Salmonella enterica serovar Typhimurium is one of the leading causes of nontyphoidal gastroenteritis of humans in the United States. Commercially processed poultry carcasses are frequently contaminated with Salmonella serovar Kentucky in the United States. The aim of the study was to detect the Salmonella virulence plasmid containing the spv genes from Salmonellaisolates recovered from commercially processed chicken carcasses. A total of 144 Salmonella isolates (SalmonellaTyphimurium, n = 72 and Salmonella Kentucky, n = 72) were used for isolation of plasmids and detection of corresponding virulence genes (spvA, spvB, and spvC). Only four (5.5%) Salmonella Typhimurium isolates tested positive for all three virulence genes and hence were classified as possessing the virulence plasmid. All isolates of Salmonella Kentucky were negative for the virulence plasmid and genes. These results indicate that the virulence plasmid, which is very common among clinical isolates of Typhimurium and other Salmonella serovars (e.g., Enteritidis, Dublin, Choleraesuis, Gallinarum, Pullorum, and Abortusovis), may not be present in a significant portion of commercially processed chicken carcass isolates.

HIGHLIGHTS

  • Virulence plasmid was detected only in 5.5% of Salmonella Typhimurium isolates.

  • All virulence plasmid–positive Salmonella isolates were positive for spvA, spvB, and spvC genes.

  • No Salmonella Kentucky isolates were positive for the virulence plasmid and genes.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, microbial contamination, Microbiology, Salmonella, Uncategorized

RASFF Alert – Foodborne Outbreak -Salmonella enterica ser. Enteritidis – Eggs

Posted on August 2, 2019 by | Leave a comment

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RASFF – foodborne outbreak suspected to be caused by Salmonella enterica ser. Enteritidis in eggs from Poland in Austria

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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 Poisoning, food recall, Food Safety, Food Safety Alert, Food Testing, foodborne outbreak, foodbourne outbreak, outbreak, Salmonella, Uncategorized

Ireland -Outbreak in Ireland tied to Romanian pork; other countries report illnesses

Posted on August 2, 2019 by | Leave a comment

Food Safety News

Eight people are part of a Salmonella outbreak in Ireland linked to pork from Romania. Five of them were admitted to hospitals. Infected people also have been identified in other countries.

One person was sickened by Salmonella Bredeney in August 2018. The other seven people fell ill between May 4 and June 3, this year. Those stricken are six adult males and two children who are siblings. There have not been any deaths.

Pork product recall

Andromi Toba de Casa was recalled last month

In mid-July, Andromi Toba de Casa 500-gram packages with a use-by date of Aug. 4 and with the lot number 17 from Romania were recalled because of the presence of Salmonella. The chilled cooked pork preparation is sold in Polonez stores throughout Ireland.

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Posted in food contamination, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, food recall, Food Safety, Food Safety Alert, foodborne disease, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Salmonella, Uncategorized

Ireland – Recall of Prymat White Mustard Seeds due to Presence of Salmonella Typhimurium

Posted on August 2, 2019 by | Leave a comment

FSAI

Summary
Category 1: For Action
Alert Notification: 2019.35
Product: Prymat Gorczyca Biała cała (white mustard seeds); pack size: 30 g
Batch Code: 1298133, ‘best-before’ date: 31/05/2022
Country Of Origin: Poland

Message:

Salmonella Typhimurium has been detected in the above batch of white mustard seeds. The implicated batch may cause illness if consumed raw.  The affected batch has been removed from sale and a point-of-sale recall notice must be displayed where the batch has been sold.

 

Nature Of Danger:

People infected with Salmonella typically develop symptoms between 12 and 36 hours after infection, but this can range between 6 and 72 hours.  The most common symptom is diarrhoea, which can sometimes be bloody.  Other symptoms may include fever, headache and abdominal cramps.  The illness usually lasts 4 to 7 days. Diarrhoea can occasionally be severe enough to require hospital admission. The elderly, infants, and those with impaired immune systems are more likely to have a severe illness.

Action Required:

Manufacturers, wholesalers, distributors, caterers & retailers:

Food businesses who have sold the implicated batch are requested to remove it from sale and clearly display a point of sale notice informing customers not to eat it.

Consumers:

Consumers are advised not to eat the implicated batch. Consumers who may have already consumed the affected batch and are feeling unwell should seek medical advice.
Mustard_seeds

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Posted in food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, food recall, Food Safety, Food Safety Alert, Food Testing, FSAI, Salmonella, Uncategorized

RASFF Alerts – Duck Carcases – Chicken Inner Fillet – Breaded Chicken Strips – Sesame Seeds – Black Pepper – Crocodile Burger – Chicken Breast Cordon Bleu – Chicken Legs

Posted on August 2, 2019 by | Leave a comment

RASFF-Logo

RASFF – Salmonella (presence /25g) in ducks carcasses from the Czech Republic in Poland

RASFF – Salmonella enterica ser. Enteritidis (presence /25g) in frozen chicken inner fillet from Poland, via the United Kingdom in France

RASFF – Salmonella (presence /25g) in frozen breaded chicken strips from Poland in France

RASFF – Salmonella (in 2 out of 5 samples /25g) in black pepper from Brazil in the Netherlands

RASFF – Salmonella (presence /25g) in sesame seeds from Sudan in Greece

RASFF – Salmonella (presence /25g) in sesame seeds from Ethiopia in Greece

RASFF – Salmonella (presence /25g) in frozen crocodile burger from Belgium in Belgium

RASFF – Salmonella enterica ser. Infantis (in 5 out of 5 samples /25g) in frozen chicken breast cordon bleu from Germany in Finland

RASFF – Salmonella enterica ser. Derby (presence /25g) in chilled chicken legs from Poland in Lithuania

RASFF – Salmonella (presence /25g) in sesame seeds from Sudan in Poland

RASFF – Salmonella (presence /25g) in sesame seeds from Nigeria, via Singapore in the Netherlands

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Posted in food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Poisoning, food recall, Food Safety, Food Safety Alert, Food Testing, RASFF, Salmonella, Salmonella Sesame Seeds, Uncategorized

RASFF Alerts – Animal Feed – Salmonella – Rape Seed Meal – Soya Bean Meal – Fish Meal

Posted on August 2, 2019 by | Leave a comment

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RASFF – Salmonella enterica ser. Münster (presence /25g) and Salmonella enterica ser. Tennessee (presence /25g) in rape seed meal from Russia in Finland

RASFF – Salmonella enterica ser. Tennessee (presence /25g) in rape seed meal from Germany in Finland

RASFF – Salmonella (presence /25g) in soya bean meal from Brazil in Poland

RASFF – Salmonella enterica ser. Kalina (in 3 out of 5 samples /25g) in fish meal from Mauritania in Greece

RASFF – Salmonella (presence /25g) in soybean meal from Brazil, via Italy, via Slovenia and via Austria in Croatia

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Posted in Animal Feed, Food Micro Blog, Food Microbiology Blog, microbial contamination, Microbiology, RASFF, Salmonella, Uncategorized