Category Archives: Food Microbiology Research

Korea – KCDC pegs salted clam as culprit behind Hepatitis A rise

Posted on September 20, 2019 by | Leave a comment

Korea Biomed

The Korea Centers for Disease Control and Prevention (KCDC) said that it has confirmed that contaminated fermented shellfish was the main culprit behind the hepatitis A outbreak this summer.

The KCDC came to the conclusions after conducting an in-depth epidemiological investigation.

The agency randomly sampled 270 of the 2,178 hepatitis A patients, diagnosed between July 28 and August 24, and surveyed whether they consumed fermented shellfish this summer. It found that 42 percent of the patients had eaten fermented shellfish during the incubation period.

KCDC also found that 80.7 percent of the 26 patients diagnosed with hepatitis A in August also ate fermented shellfish, while discovering Hepatitis A virus genes in 11 batches out of the 18 batches collected after the outbreak.

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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 recall, Food Safety, Food Safety Alert, Food Testing, Food Virus, Hepatitis A, KCDC, Uncategorized, Virus

Research – Modelling the interaction of the sakacin-producing Lactobacillus sakei CTC494 and Listeria monocytogenes in filleted gilthead sea bream (Sparus aurata) under modified atmosphere packaging at isothermal and non-isothermal conditions

Posted on September 18, 2019 by | Leave a comment

Science Direct

Highlights

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L. sakei CTC494 inhibited L. monocytogenes growth in sea bream fillets during chilled and moderate abuse temperature storage.

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L. sakei CTC494 did not increase deterioration of filleted sea bream at an initial level of ≤4 log cfu/g.

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L. sakei CTC494 showed potential as bioprotective culture for fish products.

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An approach from broth to food was developed for modelling microbial interaction.

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Models simulated the bioprotective effect of L. sakei CTC494 on L. monocytogenes in sea bream.

Abstract

The objective of this work was to quantitatively evaluate the effect of Lactobacillussakei CTC494 (sakacin-producing bioprotective strain) against Listeria monocytogenesin fish juice and to apply and validate three microbial interaction models (Jameson, modified Jameson and Lotka Volterra models) through challenge tests with gilthead sea bream (Sparus aurata) fillets under modified atmosphere packaging stored at isothermal and non-isothermal conditions. L. sakei CTC494 inhibited L. monocytogenes growth when simultaneously present in the matrix (fish juice and fish fillets) at different inoculation ratios pathogen:bioprotector (i.e. 1:1, 1:2 and 1:3). The higher the inoculation ratio, the stronger the inhibition of L. monocytogenes growth, with the ratio 1:3 yielding no growth of the pathogen. The maximum population density (Nmax) was the most affected parameter for L. monocytogenes at all inoculation ratios. According to the microbiological and sensory analysis outcomes, an initial inoculation level of 4 log cfu/g for L. sakei CTC494 would be a suitable bioprotective strategy without compromising the sensory quality of the fish product. The performance of the tested interaction models was evaluated using the Acceptable Simulation Zone approach. The Lotka Volterra model showed slightly better fit than the Jameson-based models with 75–92% out of the observed counts falling into the Acceptable Simulation Zone, indicating a satisfactory model performance. The evaluated interaction models could be used as predictive modelling tool to simulate the simultaneous behaviour of bacteriocin-producing Lactobacillus strains and L. monocytogenes; thus, supporting the design and optimization of bioprotective culture-based strategies against L. monocytogenes in minimally processed fish products.

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

Research – Inactivation of Salmonella, Listeria monocytogenes and Enterococcus faecium NRRL B-2354 in a selection of low moisture foods

Posted on September 17, 2019 by | Leave a comment

Science Direct

Highlights

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Pathogens or surrogate survived well in samples during storage (21 days at 16 °C).

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Heat resistance did not change significantly throughout the storage period.

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Viability of pathogens or surrogate was adequate for inactivation/validation studies.

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E. faecium NRRL B2354 was a suitable surrogate in tested products except confectionery.

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Pathogens were inactivated by heating to 112 °C solid foods in sealed thermal cells.

Abstract

The aims of this study were to obtain data on survival and heat resistance of cocktails of Salmonella, Listeria monocytogenes and the surrogate Enterococcus faecium(NRRL B-2354) in four low moisture foods (confectionery formulation, chicken meat powder, pet food and savoury seasoning) during storage before processing. Inoculated samples were stored at 16 °C and cell viability examined at day 0, 3, 7 and 21. At each time point, the heat resistance at 80 °C was determined. The purpose was to determine a suitable storage time of inoculated foods that can be applied in heat resistance studies or process validations with similar cell viability and heat resistance characteristics. The main inactivation study was carried out within 7 days after inoculation, the heat resistance of each bacterial cocktail was evaluated in each low moisture food heated in thermal cells exposed to temperatures between 70 and 140 °C. The Weibull model and the first order kinetics (D-value) were used to express inactivation data and calculate the heating time to achieve 5 log reduction at each temperature.

Results showed that the pathogens Salmonella and L. monocytogenes and the surrogate E. faecium NRRL B-2354, can survive well (maximum reduction < 0.8 log) in low moisture foods maintained at 16 °C, as simulation of warehouse raw material storage in winter and before processing. The D80 value of the pathogens and surrogate did not significantly change during the 21 day storage (p > 0.05). The inactivation kinetics of the pathogens and surrogate at temperatures between 70 and 140 °C, were different between each organism and product. E. faecium NRRL B-2354 was a suitable Salmonella surrogate for three of the low moisture foods studied, but not for the sugar-containing confectionery formulation. Heating low moisture food in moisture-tight environments (thermal cells) to 111.2, 105.3 or 111.8 °C can inactivate 5 log of Salmonella, L. monocytogenes or E. faecium NRRL B-2354 respectively.

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

Research – Comparison of pH effects on ohmic heating and conventional heating for inactivation of Escherichia coli O157:H7, Salmonella enterica Serovar Typhimurium and Listeria monocytogenes in orange juice

Posted on September 16, 2019 by | Leave a comment

Science Direct

Highlights

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Effect of pH on ohmic heating compared to conventional heating was investigated.

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Adjusting pH has significant effect on the heating rate of ohmic heating.

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Unusual tendency of pathogen inactivation was identified in ohmic heating.

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Quality aspects of samples were not severely degraded regardless of pH.

Abstract

The objective of the current study is to identify the influence of acidity on ohmic heating compared to conventional heating for inactivation of food-borne pathogensin orange juice. For conventional heating, the heating rate was not significantly different (P > 0.05) regardless of pH and pathogens were inactivated more effectively at lower pH. However, different patterns were observed for ohmic heating. Although temperature and electrical conductivity were not greatly affected by lowering pH, temperature increased more rapidly with increasing pH due to higher electrical conductivity. Also, the inactivation patterns were significantly different (P < 0.05) from conventional heating. While Salmonella Typhimurium was inactivated most rapidly at pH 2.5, Escherichia coli O157:H7 and Listeria monocytogenes were inactivated most rapidly at pH 4.5. When pathogens were exposed to each heating method at a fixed temperature, additional effects of ohmic heating were not observed. Also, the overall quality of orange juice subjected to ohmic heating was not greatly affected at any pH level. Therefore, increasing as well as lowering pH can also be considered effective ways to optimize pasteurization of orange juice when using ohmic heating. The different characteristics of ohmic heating compared to conventional heating indicate the necessity of a new approach.

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

Research – Antibiotic resistant phenotypes of Staphylococcus aureus isolated from fresh and fermented milk in parts of Nasarawa State, Nigeria

Posted on September 15, 2019 by | Leave a comment

Academic Journals

Abstract

This work was aimed at determining the occurrence and antibiogram of Staphylococcus aureusisolated from fresh and fermented milk samples in parts of Nasarawa State, Nigeria. A total of 180 samples comprising of fresh raw milk, bulk milk, nono, and kindirmo were collected over a period of 6 months (May to October, 2017). Standard microbiological procedures were employed in the isolation, identification, characterisation, and determination of the antibiogram of S. aureus from the milk samples. Characterisation of the S. aureus isolates was by morphological, biochemical characteristics using conventional methods, Microgen® STAPH-ID kits. Confirmed isolates were tested for susceptibility or resistance to a panel of 11 commonly used antibiotics using the agar disc diffusion technique. Out of the 180 milk samples examined, 9 S. aureus were isolated giving a prevalence of 5.0%. The occurrence of S. aureus was higher in nono (12.1%) and kindirmo (10.6%) than in fresh raw milk (5.9%). The high occurrence of S. aureus in nono disproved the assertion that fermented foods are not good media for the survival and growth of S. aureus. The antibiotic susceptibility profile of the S. aureus isolates indicated all of the nine isolates were completely resistant to cefoxitin, ampicillin, and amoxicillin/clavulanic acid. The isolates were moderately resistant to erythromycin (22.2%), sulphamethoxazole/trimethoprim (22.2%), and tetracycline (44.4%). Five antibiotic resistance patterns were recorded among the isolates. All of the isolates had a multiple antibiotics resistance (MAR) index of 0.3 and above, an indication of possible antibiotic misuse in the areas studied.

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Posted in Antibiotic Resistance, antimicrobial resistance, Antimicrobials, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, microbial contamination, Microbiology, Staphylococcus aureus, Uncategorized

Research – Antimicrobial resistance profile of Escherichia coli isolates recovered from diarrheic patients at Selam Health Center, Addis Ababa, Ethiopia

Posted on September 14, 2019 by | Leave a comment

Academic Journals

Abstract

Antimicrobials have been playing an important role in preventing illness and death associated with infections due to bacteria. However, the emergence and spread of resistance by pathogens have decreased the effectiveness of the commonly prescribed antimicrobials. Intestinal Escherichia coli are among bacterial pathogens that are endowed with such resistance traits because they are important source and reservoir of genes that encode antimicrobial resistance. To determine the antimicrobial resistance profile of fecal isolates of E. coli from diarrheic patients. Stool samples were collected consecutively from 100 individuals who visited Selam Health Center during the study period, April to June 2018. Samples were collected and transported under sterile condition to the National Clinical Bacteriology and Mycology reference Laboratory, Ethiopian Public Health Institute. The samples were streaked on MacConkey agar and incubated overnight at 37°C. E. coli isolates were further confirmed using conventional biochemical tests. Antimicrobial susceptibility status was determined using the disk diffusion method on Mueller Hinton agar as recommended by the Clinical Laboratory Standard Institute. The raw data was compiled and entered to spreadsheet and analysis was done using SPSS Version 20 with p-value ≤0.05 considered statistically significant. Out of the 100 patients, 43 were female and the rest were male. Confirmed E. coli were isolated from 73 individuals. Antimicrobial susceptibility testing showed that E. coli isolated in this study were highly resistant to trimethoprim-sulfamethoxazole 49 (67.1%) and amoxicillin-clavulanic acid 47(64.4 %). No isolates showed resistance to gentamicin and tobramicin.  Of all the isolates, 11(15.1%) were multidrug resistant. No association was observed between antimicrobial resistance status and sex of individuals included in this study. However, there was an association between age and resistance patterns. Resistance to commonly prescribed antibiotics among E. coli isolated in this study was high and a considerable proportions of the strains were multidrug resistant. This is an indication for an alarming rate of resistance of intestinal E. coli to first line antimicrobials. To reduce the problem, regular monitoring and education for the community are very important.

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Posted in Antibiotic Resistance, antimicrobial resistance, Antimicrobials, E.coli, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Technology, microbial contamination, Microbiology, Uncategorized

Research – Novel Bacteriocin a Promising New Treatment for Resistant Listeria monocytogenes

Posted on September 12, 2019 by | Leave a comment

Contagion Live

A novel bacteriocin appears promising as a new treatment option for antibiotic-resistant Listeria monocytogenes infection just as a multistate outbreak of the foodborne bacteria has claimed 2 lives in the United States.

With a fatality rate that can reach as high as 30%, L monocytogenes is considered a pressing public health threat that can have a serious impact on immunocompromised individuals and pregnant women, newborn children, and the elderly.

Because of its high mortality rate and increasing resistance to currently available antibiotics, treating L monocytogenes is becoming more and more challenging. But investigators with RMIT University in Melbourne, Australia, have discovered a promising new treatment in the form of a bacteriocin produced by Lactobacillus plantarum B21. The research team presented their findings at the American Society for Microbiology (ASM) and the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) Conference on Drug Development to Meet the Challenge of Antimicrobial Resistance.

Investigators played with multiple culture conditions to find a set that would foster high bacterial growth and/or high bacteriocin production. They also used gas chromatography mass spectrometry (GC‐MS)-based metabolomics to evaluate cellular and functional behavior of L plantarum B21. The structure of bacteriocin was analyzed using 2‐dimensional nuclear magnetic resonance spectroscopy (NMR). In order to assess the effectiveness of bacteriocin against a range of target strains of bacteria, the team relied on well diffusion assays and electron microscopy.

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

USA – Shigella Outbreak in Amador County

Posted on September 9, 2019 by | Leave a comment

Outbreak News Today

Shigella - kswfoodworld

Image CDC

Amador County health officials announced this week that they are currently investigating a Shigella outbreak in their county. According to the announcement, there is a “significant increase in acute frequent diarrhea is being reported in Amador County.” The county, however, did not state how many illnesses are involved or the medical status of those who are sick. 
It is believed that the health department has determined the source but has been mum about naming it. The health department’s statement noted that: “Amador County Environmental Health and Public Health are completing an investigation and have enforced food safety practices at a lone establishment associated with reports of this illness.”

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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 Microbiology Research, Food Pathogen, food recall, Food Safety, Food Safety Alert, Food Testing, foodborne outbreak, foodbourne outbreak, outbreak, Shigella, Uncategorized

UK – Major retailers publish Campylobacter results for April-June 2019

Posted on September 6, 2019 by | Leave a comment

FSA

The top nine retailers across the UK have today published their latest testing results on campylobacter contamination in UK-produced fresh whole chickens (covering samples tested from April to June 2019).

The latest figures show that on average, across the major retailers, 3.6% of chickens tested positive for the highest level of contamination. These are the chickens carrying more than 1,000 colony forming units per gram (cfu/g) of campylobacter.

Results

Contamination levels July-September 2018 October-December 2018 January-March 2019 April-June 2019
cfu/g less than 10 58.8% 63.1% 55.4% 59%
cfu/g 10-99 26.7% 22.3% 25.3% 25.3%
cfu/g 100-1000 11% 11.4% 15.8% 12.1%
cfu/g over 1000 3.5% 3.1% 3.5% 3.6%

Results by retailer for April – June 2019

The sampling and analyses are carried out in accordance with protocols laid down by the FSA and agreed by Industry.

Background information

We have been testing chickens for campylobacter since February 2014 and publishing the results as part of a campaign to bring together the whole food chain to tackle the problem. Campylobacter is the most common cause of food poisoning in the UK.

In September 2017 we announced changes to the survey, with major retailers carrying out their own sampling and publishing their results under robust protocols laid down by the FSA. We are continuing to sample fresh whole chickens sold at retail, however, the focus is now on the smaller retailers and the independent market.

Consumer advice

Chicken is safe if consumers follow good kitchen practice:

  • Cover and chill raw chicken – cover raw chicken and store at the bottom of the fridge so juices cannot drip onto other foods and contaminate them with food poisoning bacteria such as campylobacter
  • Don’t wash raw chicken – thorough cooking will kill any bacteria present, including campylobacter, while washing chicken can spread germs by splashing
  • Wash used utensils – thoroughly wash and clean all utensils, chopping boards and surfaces used to prepare raw chicken
  • Wash hands thoroughly with soap and warm water, after handling raw chicken – this helps stop the spread of campylobacter by avoiding cross-contamination
  • Cook chicken thoroughly – make sure chicken is steaming hot all the way through before serving. Cut into the thickest part of the meat and check that it is steaming hot with no pink meat and that the juices run clear.

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

RASFF Alerts – Aflatoxin – Par Boiled Brown Rice – Groundnut Kernels – Hazlenut Flour – Peanuts

Posted on September 6, 2019 by | Leave a comment

RASFF-Logo

RASFF – aflatoxins (B1 = 4.09 µg/kg – ppb) in par boiled brown rice from Myanmar in Poland

RASFF – aflatoxins (B1 = 5 / B1 = 8.6; Tot. = 18 µg/kg – ppb) in groundnut kernels from Argentina in the Netherlands

RASFF – aflatoxins (B1 = 9.4 µg/kg – ppb) in hazelnut flour from Georgia in Bulgaria

RASFF – aflatoxins (B1 = 20; Tot. = 23 µg/kg – ppb) in peanuts from Egypt in the Netherlands

RASFF – aflatoxins (B1 = 6.5 µg/kg – ppb) in peanuts from the United States in the Netherlands

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Posted in Aflatoxin, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Poisoning, food recall, Food Safety, Food Safety Alert, Food Testing, Food Toxin, Mycotoxin, RASFF, Uncategorized