Category Archives: E.coli

Research – Effects of Package Atmosphere and Storage Conditions on Minimizing Risk of Escherichia coli O157:H7 in Packaged Fresh Baby Spinach

Posted on April 27, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

Packaged fresh spinach has been associated with outbreaks of illness caused by Escherichia coli O157:H7. The purpose of this study was to assess the behavior of E. coli O157:H7 in packaged baby spinach in response to storage conditions of temperature and package atmosphere and including effects of inoculation level, spinach leaf damage (cut leaves), internalized or leaf surface contamination, exposure to hypochlorite sanitizer, and package size. Behavior of E. coli O157:H7 inoculated at 2 and 4 log CFU/g on spinach packaged in polymer bags composed of a two-layer laminate (polypropylene and polyethylene) and stored under atmospheres of 20% O2–3% CO2 and 0% O2–15% CO2 (aerobic and anaerobic, respectively) was assessed at 5, 7, 12, and 15°C for up to 14 days. Growth kinetics were calculated using DMFit software. Temperature decreases progressively diminished growth or survival of the pathogen, and an aerobic package atmosphere resulted in longer lag times (4 to 6 days) and lower population levels (0.2 to 1.4 log CFU/g) compared with the anaerobic atmosphere at 15°C. Internalized contamination, leaf cuts, or exposure to 100 ppm of hypochlorite did not result in changes in pathogen behavior compared with controls; however, a growth minimization trend consisting of longer lag times and lower population levels was repeatedly observed in the aerobic compared with the anaerobic package atmospheres. In contrast, growth of indigenous mesophiles and Enterobacteriaceae was unaffected by package atmosphere. Spinach stored at 5 to 7°C in two sizes (5 and 16 oz) of polyethylene terephthalate clamshell packages with ambient air atmospheres was more likely to progress to lower-oxygen conditions in 16-oz compared with 5-oz packages after 7 days of storage (P < 0.05). Practices to maintain aerobic conditions within the package, as well as storage of the package at low temperature, are ways to limit growth of E. coli O157:H7 in packaged spinach.

HIGHLIGHTS

  • Cold aerobic conditions limited survival of E. coli O157:H7 in packaged spinach.

  • Low-oxygen atmosphere increased pathogen risk in temperature-abused packages.

  • Internalization, leaf cuts, and hypochlorite stress did not increase pathogen risk.

  • Large spinach packages trended toward lower-oxygen conditions more than small packages.

  • Maintaining cold aerobic conditions can limit pathogen risk in packaged spinach.

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

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

Posted on April 27, 2019 by | Leave a comment

Journal of Food Protection

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, Food Microbiology Blog, Food Pathogen, microbial contamination, Microbiology, Pathogen, Salmonella, Staphylococcus aureus, Uncategorized

Research – Comparison of Antimicrobial Treatments Applied via Conventional or Handheld Electrostatic Spray To Reduce Shiga Toxin–Producing Escherichia coli on Chilled Beef Outside Rounds

Posted on April 27, 2019 by | Leave a comment

Journal of Food Protection

The purpose of this study was to compare the efficacy of different antimicrobial interventions applied via either conventional spray (CS) or handheld electrostatic spray (ESS) to reduce Shiga toxin–producing Escherichia coli (STEC) on fresh beef surfaces. Hot-boned outside rounds (ORs) were inoculated within 1 h after harvest with a cocktail of eight isolates consisting of 8 O157 and non-O157 serogroups of STEC (STEC8). ORs were hung on sterile meat hooks at 4°C for 36 h to simulate a contaminated full carcass side in the chiller. ORs were then treated with lactic acid (LA; 4.5%, w/v), 3.0% lauric arginate ester (LAE), 0.8% cetylpyridinium chloride, 200 mg/L peracetic acid, 3 mg/L chlorine dioxide, 5 mg/L ClO2, or tap water by using CS or ESS. Temperatures of LA and peracetic acid were set at 55 and 42°C before spraying, whereas all other solutions were applied at room temperature (25°C). Pretreatment and posttreatment STEC8-inoculated beef tissue samples were aseptically collected to evaluate the efficacy of interventions by application method (CS or ESS). LA applied with CS achieved the greatest reduction in STEC8 numbers (3.3 log CFU/cm2) compared with all other treatments: 0.2 log CFU/cm2 (tap water) to 2.3 log CFU/cm2 (LAE). Only for LA did a significant difference arise in mean STEC8 reductions between CS and ESS applications (3.2 versus 1.7 log CFU/cm2, respectively). Among the treatments applied with ESS, LAE produced the greatest reduction of STEC8. Antimicrobial interventions applied via conventional wand or cabinet-applied technologies can reduce the O157 and non-O157 STEC on fresh beef carcass surfaces, reducing transmission to beef consumers.

HIGHLIGHTS

  • We found no advantage in the use of electrostatic spray to reduce STEC8 on cold beef.

  • Greatest reductions in STEC8 were achieved by lactic acid with conventional spray.

  • Lauric arginate ester was the second best antimicrobial agent at reducing STEC8.

  • Lactic acid reduced pH on the beef surface significantly.

  • There was no effect of antimicrobial solution on temperature increase on beef outside rounds.

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Posted in E.coli, E.coli O157, E.coli O157:H7, Food Microbiology, Food Microbiology Blog, Food Technology, microbial contamination, Microbiology, STEC, Uncategorized

USA – North Star Imports Ground Beef Recalled For E. coli O103 Contamination

Posted on April 26, 2019 by | Leave a comment

Food Poisoning Bulletin

Grant Park Packing of Franklin, Illinois is recalling about 53,200 pounds of North Star Imports raw ground beef products that may be contaminated with E. coli O103. The USDA notice states that “Further testing is ongoing to determine if the recalled ground beef products are related to the E. coli O103 outbreak.” That outbreak has sickened at least 156 people in 10 states.

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Posted in E.coli, E.coli O103, 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, Food Toxin, Uncategorized

RASFF Alert – STEC E.coli -O157 – Chilled Cow Carcases

Posted on April 26, 2019 by | Leave a comment

RASFF-Logo

RASFF – shigatoxin-producing Escherichia coli (stx1-, stx2+, eae+, O157+) in chilled cow carcasses from Belgium in Belgium

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Posted in E.coli, E.coli O157, E.coli O157:H7, eae, 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, STEC, STX 1, STX 2, Uncategorized

USA – E.coli O103 Outbreak Updates

Posted on April 26, 2019 by | Leave a comment

FSIS USDA

K2D Foods Recalls Raw Ground Beef Products Due to Possible E. coli O103 Contamination

FSIS USDA

Grant Park Packing Recalls Raw Ground Beef Products Due to Possible E. coli O103 Contamination

Food Poisoning Bulletin

The ground beef E. coli O103 outbreak has now sickened at least 156 people in 10 states. according to the Centers for Disease Control and Prevention (CDC). Twenty people are hospitalized because they are so ill. UPDATE: K2D Foods has recalled more than 100,000 pounds of ground beef for possible E. coli O103 contamination. But the recall notice states that “At this time, there is no definitive link between this positive product and the ongoing E. coli O103 outbreak.”

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Posted in E.coli, E.coli O103, 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, Food Toxin, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Uncategorized

Research – Limitation of microbial spoilage of rainbow trout fillets using characterized thyme oil antibacterial nanoemulsions

Posted on April 24, 2019 by | Leave a comment

Wiley Online

Abstract

Thyme oil nanoemulsions (TONa and TONb), having 219 nm and 163 nm diameters, were successfully prepared by using sonication technique. Zeta potential (ZP) and polydispersity indexes (PDI) of TONa and TONb were defined to be 19.77, 0.24 and −24.80, 0.054, respectively. It was determined that zeta size values of TONs might have played a role on the inhibition of Pseudomonas aeruginosa, Escherichia coli, Salmonella typhimurium. All bacteria tested by agar diffusion method were gram‐negative bacteria that could be mostly found in fish fillets. Within 9 days cold storage period, TMAB growth in fish fillets treated with TONb was successfully reduced from 6.42 to 4.62 log CFU/g (change: 28%). In addition, as compared with control group samples, TPB growth of the same group was limited by 1.51 log CFU/g (from 7.93 to 6.42 log CFU/g). The results suggested that treatment of the fish fillets with the TONs would be a useful and practical nano application to delay microbial growth in fish fillets.

Practical applications

Thyme oil nanoemulsions (TONa and TONb) with a lower diameter than 219 nm have been successfully obtained. Antibacterial effects of TONa and TONb nanoemulsions have been revealed before treatment with fish fillets. The results revealed that TONs could be successfully used for the limitation of microbial spoilage of fish fillets stored at 4°C for 9 days. In this respect, the nano application with rapid and cost‐effective has been presented for the fishery processing industry.

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Posted in E.coli, Food Micro Blog, Food Microbiology Blog, microbial contamination, Microbiology, Pseudomonas, Pseudomonas aeruginosa, Salmonella, Uncategorized

RASFF Alerts – STEC E.coli – Filet Americaine – Chilled Boneless Meat

Posted on April 23, 2019 by | Leave a comment

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RASFF – shigatoxin-producing Escherichia coli (stx +, eae + /25g) in filet americaine from Belgium in Belgium

RASFF – shigatoxin-producing Escherichia coli (O113: H21 – stx2+ /25g) in chilled boneless meat from Argentina in Germany

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Posted in E.coli, E.coli O113, eae, 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, Food Toxin, RASFF, STEC, STX 1, STX 2, Uncategorized

RASFF Alert- E.coli – Coriander

Posted on April 23, 2019 by | Leave a comment

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RASFF – high count of Escherichia coli (1500 CFU/g) in coriander from Thailand in Norway

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Posted in E.coli, 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, Uncategorized

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

Posted on April 19, 2019 by | Leave a comment

Journal of Food Protection

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.

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