Category Archives: Food Microbiology Research

Research -Influence of surface properties of produce and food contact surfaces on the efficacy of chlorine dioxide gas for the inactivation of foodborne pathogens

Posted on November 24, 2019 by | Leave a comment

Science Direct

The objective of this study was to evaluate the influence of surface properties of produce and food contact surfaces on the antimicrobial effect of chlorine dioxide (ClO2) gas against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes. The hydrophobicity of the selected surfaces was evaluated by water contact angle measurements. White light scanning interferometry (WLSI) was used to acquire surface roughness values of each surface. Produce and food contact surfaces inoculated with foodborne pathogens were treated with 20 ppmv ClO2 gas for 5, 10, and 15 min. As treatment time increased, different levels of inactivation of the three pathogens were observed among the samples. Contact angles of produce and food contact surfaces were highly and negatively correlated with the log reduction of all three pathogens. There were generally weaker correlations between the roughness values of sample surfaces and microbial reduction compared to those between hydrophobicity and microbial reduction. The results of this study showed that surface hydrophobicity is a more important factor relative to bacterial inactivation by ClO2 gas from the surface than is surface roughness. Also, the existence of crevices with features of similar size to the pathogen cell was more important than the Ra and Rq values in the inactivation of pathogens.

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

Research – Population dynamics of Salmonella spp. and Shigella spp. in ready‐to‐eat Mediterranean vegetable salads

Posted on November 23, 2019 by | Leave a comment

Wiley Online

Abstract

This study evaluated the behavior of Salmonella and Shigella (5–6 log CFU/g) in tomato–cucumber (TC) salad without additives (control), TC with 1.0% lemon juice and 0.5% salt, TC with 10% wt/wt tahini, coleslaw, and toum sauce at 4, 10, or 24°C for 5 days. At 4°C, both pathogens survived well in all salads, with a 0.2–1.6 log CFU/g reduction after 5 days (except for toum sauce with >3.5 log CFU/g reduction after 4 days). At 10°C, Salmonella in the different TC salads remained constant, whereas Shigella numbers significantly increased by 1.0–1.7 log CFU/g after 5 days. Yet, both pathogens significantly decreased by 1.2–1.4 log CFU/g in coleslaw after 5 days and by >3.5 log CFU/g in toum sauce after 3 days. At 24°C, Salmonella significantly increased in TC salad without additives by 1.4 log CFU/g after 5 days and were below the detection level in the other types of salad after 5 days. However, Shigella numbers significantly increased by 1.0 log CFU/g in TC with tahini, but they significantly declined by 1.9–2.9 log CFU/g in TC salads after 5 days, and the pathogen was not detected in coleslaw and toum sauce after 4 days.

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

Research -Processing plant and machinery sanitation and hygiene practices associate with Listeria monocytogenes occurrence in ready-to-eat fish products

Posted on November 23, 2019 by | Leave a comment

Science Direct

Listeria monocytogenes causes the foodborne illness listeriosis, which exhibits high fatality among people in risk groups. The incidence of listeriosis has increased in Europe, which raises concerns about L. monocytogenes occurrence in foodstuffs. Ready-to-eat seafood products are considered particularly risky vehicles. Poor hygiene at processing facilities predisposes them to L. monocytogenes contamination, which can be controlled by stringent self-checking system measures. We examined the association of fish-processing plant operational and hygiene practices with the occurrence of L. monocytogenes in vacuum-packaged gravad (cold-salted) and cold-smoked salmon and rainbow trout products. Product sampling of 21 fish-processing plants was carried out, and operational procedures relating to L. monocytogenes control were surveyed using an in-depth risk assessment questionnaire. L. monocytogenes occurred only in sliced and mainly in gravad products of seven fish-processing plants. Shortages in preventive measures were discovered predominantly among the L. monocytogenes positive fish-processing plants. Using generalized linear modeling, we identified the following features associated with L. monocytogenes product contamination: the number of processing machines, deficiencies in the processing environment and machinery sanitation, and staff movement from areas of low toward high hygiene. Furthermore, performing frequent periodic thorough sanitation alongside everyday sanitation practices associated with a decreased risk of product contamination.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbiology, Research, Technology, Uncategorized

Research – Unusual Salmonella widespread in turkeys still sickening people- USA

Posted on November 22, 2019 by | Leave a comment

CIDRAP

Though the investigation into a Salmonella Reading outbreak with several unusual features and linked to raw turkey products ended in April, the outbreak strain has become widespread in the turkey production industry, and cases continue to be reported, according to a new report today.

Public health officials from the US Centers for Disease Control and Prevention and health partners from several states and the District of Columbia fleshed out more details about the investigation and the unique outbreak in the latest issue of Morbidity and Mortality Weekly Report (MMWR). Given the lingering threat, they also urged the industry and consumers to continue taking steps to reduce contamination.

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

Europe -How Common is Legionnaires’ Disease in Europe?

Posted on November 21, 2019 by | Leave a comment

Legionella Control

In this article the water safety experts at Legionella Control International ask the question… how common is Legionnaires’ disease in Europe, and what can be done to prevent it? It examines data from the ECDC (European Centre for Disease Prevention and Control) including records of how many people catch Legionnaires’ disease in Europe, and typical mortality rates. It then looks at what key steps can be taken to control the spread of the disease, including legionella risk assessment and the development and implementation of a Water Safety Plan or WSP.

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Posted in Contaminated water, Food Micro Blog, Food Microbiology, Food Microbiology Research, Legionella, microbial contamination, Microbiology, Research, Uncategorized, Water, water microbiology

Research – Stability of Listeria monocytogenes in wheat flour during extended storage and isothermal treatment

Posted on November 21, 2019 by | Leave a comment

Science Direct

Foodborne pathogens including Salmonella have been implicated in recent recalls of low-water activity (aw) foods, such as peanut butter, almond flour, wheat, flour and dry milk powder, and are primary concerns for the microbiological safety of dry food products. Although there are an increasing number of studies on Salmonella thermal resistance conducted in low-moisture foods, little information is available on Listeria monocytogenes thermal resistance in those products. This study evaluated the survival of L. monocytogenes in wheat flour during long-term storage as well as its thermal resistance in wheat flour equilibrated to aw 0.30, 0.45, and 0.60. L. monocytogenes survived in wheat flour at both aw 0.31 and 0.56 during 6 months of storage at room temperature, with populations decreasing about 2.52 and 6.27 logs at aw 0.31 and 0.56, respectively. Equilibration in low-aw flour enabled L. monocytogenes to become more resistant to thermal treatment. At treatment temperature between 70 and 80 °C, D-values increased with decreasing aw. For aw 0.30. 0.45, and 0.60 (measured at room temperature), respectively, D-value (in min) ranges for 70–80 °C were 37.10–7.08, 17.44–3.13, and 16.85–1.59. The z-values were 12.9, 14.2, and 9.9 °C for aw 0.30, 0.45, and 0.60, respectively. These data highlight the need for vigilance when processing dry foods, and provide valuable information for the industry to validate thermal processing for control of L. monocytogenes in low-moisture foods. This study also offers insight into the development of thermal inactivation strategies to control L. monocytogenes and other foodborne pathogens in foods with similar matrices.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbiology, Research, Salmonella, Technology, Uncategorized

USA- Romaine in the cross-hairs – FDA to test lettuce for pathogens

Posted on November 20, 2019 by | Leave a comment

Food Poison Journal

Image CDC

The FDA is conducting a small, focused assignment to collect samples of raw agricultural commodity (RAC) romaine lettuce to test for Salmonella spp. and pathogenic Escherichia coli (also known as Shiga Toxin-producing E. coli or STEC), microbial hazards repeatedly linked to foodborne illnesses associated with romaine lettuce consumption. The assignment begins this month (November 2019) and is expected to last one year.

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

Research -First report of Escherichia coli O157:H7 in ready-to-eat sushi.

Posted on November 19, 2019 by | Leave a comment

Europe PMC

AIMS:The aim of this study was to evaluate the microbiological quality of commercially prepared ready-to-eat (RTE) sushi by enumerating aerobic mesophilic bacteria (AMB) and thermotolerant coliforms (TC) and detecting Escherichia coli and Salmonella ssp. An isolate was identified as E. coli O157:H7 which was evaluated for its virulence and antimicrobial resistance profiling as well as its ability to form biofilms on stainless steel. METHODS AND RESULTS:There were four sampling events in seven establishments, totalling 28 pools of sushi samples. Mean AMB counts ranged between 5·2 and 7·7 log CFU per gram. The enumeration of TC varied between 2·1 and 2·7 log MPN per gram. Salmonella ssp. were not detected, and one sample was positive for E. coli and was identified as E. coli O157:H7. To the best of our knowledge, this is the first report of E. coli O157:H7 in sushi samples in the world literature. This isolate presented virulence genes stx1, stx2, eae and hlyA. It was also susceptible to 14 antimicrobials tested and had the ability to form biofilms on stainless steel. CONCLUSIONS:There is a need to improve the good hygiene practices adopted in establishments selling sushi in the city of Pelotas, Brazil. In addition, the isolated E. coli O157:H7 carries a range of important virulence genes being a potential risk to consumer health, as sushi is a RTE food. This isolate also presents biofilm formation ability, therefore, may trigger a constant source of contamination in the production line of this food. SIGNIFICANCE AND IMPACT OF THE STUDY:The increase in the consumption of sushi worldwide attracts attention regarding the microbiological point of view, since it is a ready-to-eat food. To our knowledge, this was the first time that E. coli O157:H7 was identified in sushi samples.

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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 Microbiology Research, Food Pathogen, Food Poisoning, Food Safety, Food Safety Alert, Food Testing, Food Toxin, Research, Salmonella, STEC, STEC E.coli, Uncategorized

Singapore -Eating raw pig liver from local market may raise chances of contracting Hepatitis E virus liver disease

Posted on November 18, 2019 by | Leave a comment

Alvinology

Do you like to eat raw liver? Is liver pâté one of your favorite dishes? You may want to think twice before ingesting such a meal again, as researchers at the Singapore General Hospital have found definite similarities between the virus strains of Hepatitis E virus or (HEV) in pig liver and human liver.

 

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Posted in food contamination, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Pathogen, Food Safety, Food Testing, Food Virus, Hepatitis E, Research, Uncategorized, Virus

Research – Decontamination of Bacillus cereus in cardamom (Elettaria cardamomum) seeds by infrared radiation and modeling of microbial inactivation through experimental models

Posted on November 16, 2019 by | Leave a comment

Wiley Online 

In this work, infrared (IR) irradiation was used for inactivation of Bacillus cereus in cardamom seeds. The effect of IR power (100, 200, and 300 W), sample distance from radiation source (5, 10, and 15 cm) and holding times (0–11 min) was investigated on B. cereus count, as well as cardamom seeds color and temperature profiles. Inactivation of B. cereus on cardamom seeds during IR processing was demonstrated by experimental models. The highest reduction of B. cereus count (5.11 Log CFU/g) was achieved after 8 min IR irradiation at 300 W power and 15 cm distance. Measurement of temperature profiles revealed that there was a significant difference (p < .05) between surface and center temperatures of the cardamom seeds. The green color (a* value) of cardamom seeds was slightly affected and the highest color change was observed at 200 W IR, 10 cm distance and 10 min irradiation that resulted in an increase of a* from −3.05 ± 0.96 to −0.05 ± 0.44. In conclusion, IR irradiation could be successful for decontamination of cardamom seeds without severe alteration of its quality. Among the experimental models for microbial inactivation during IR processing, the Double Weibull model had the highest coefficient value of determination (R2 = 0.9966).

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Posted in Bacillus, Bacillus cereus, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Technology, microbial contamination, Microbiology, Research, Technology, Uncategorized