Category Archives: Microbiology

Research – Enhancement of the Antibiofilm Activity of Nisin against Listeria monocytogenes Using Food Plant Extracts

Posted on March 15, 2023 by | Leave a comment

MDPI

Abstract

Listeria monocytogenes is a foodborne pathogen exhibiting a high mortality rate. In addition to the robust tolerance to environmental stress, the ability of L. monocytogenes to develop biofilms increases the risk of contaminating food processing facilities and ultimately foods. This study aims to develop a synergistic approach to better control Listeria biofilms using nisin, the only bacteriocin approved as a food preservative, in combination with gallic-acid-rich food plant extracts. Biofilm assays in the presence of nisin and gallic acid or its derivatives revealed that gallic acid significantly decreased the level of biofilm formation in L. monocytogenes, whereas ethyl gallate, propyl gallate, and lauryl gallate enhanced biofilm production. As gallic acid is widely distributed in plants, we examined whether extracts from gallic-acid-rich food plants, such as clove, chestnut, oregano, and sage, may generate similar antibiofilm effects. Remarkably, sage extracts enhanced the antibiofilm activity of nisin against L. monocytogenes; however, the other tested extracts increased biofilm formation, particularly at high concentrations. Moreover, sage extracts and nisin combinations significantly reduced the biofilm formation of L. monocytogenes on stainless steel. Sage is a common food spice and has various beneficial health effects, including antioxidation and anti-cancer properties. The findings in this study demonstrate that sage extracts can be potentially combined with nisin to prevent biofilm production in L. monocytogenes.

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Posted in Biofilm, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Nisin

Sweden – No cases yet linked to most recent Salmonella finding in Sweden

Posted on March 14, 2023 by | Leave a comment

Food Safety News

hazegg.jpg

A second alert for Salmonella at an egg producer in Sweden does not appear to have resulted in more people getting sick, according to health officials.

The Public Health Agency of Sweden (Folkhälsomyndigheten) said new findings of Salmonella at the site of the same company were made in mid-February. This prompted another wave of recalls in February and March.

In late December 2022, Salmonella Enteritidis was identified at CA Cedergren, a major producer, in one of the egg-laying stables during a routine environmental sampling check. Eggs were then recalled by Coop, Axfood, ICA, Lidl, and Kronägg. 

Investigations found Salmonella from the production environment in December was identical to isolates from sick people.

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Posted in Decontamination Microbial, food bourne outbreak, Food Illness, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Illness, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, outbreak, Salmonella, Salmonella in Eggs

Research – Exploring the Link Between Legionnaires’ Disease and Pneumonia

Posted on March 14, 2023 by | Leave a comment
Legionella Control
CDC legionella

Most of us have heard of Legionnaires’ disease and we are all likely to be aware of pneumonia too, but did you know there is a link between the two?

There are many illnesses and conditions that can affect the lungs. Legionnaires’ disease presents as a serious type of pneumonia. This is an inflammation of the lungs. Below, we’ll go into more detail about the link between Legionnaires’ disease and pneumonia. Both can be fatal, particularly among those who are more susceptible to this type of infection than others.

A version of this story exploring the link between Legionnaires’ disease and pneumonia appeared in Legionella Control International’s newsletter. To get it in your inbox, sign up for free at the link above

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Posted in Contaminated water, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Legionella, Legionnaires’ disease, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Uncategorized, Water, water microbiology, Water Safety

USA – FDA wants infant formula manufacturers to step up work to prevent contamination

Posted on March 13, 2023 by | Leave a comment

Food Safety News

Top FDA officials are calling on manufacturers of infant formula to clean up their act.

In a letter this week Robert M. Califf, FDA Commissioner, and Susan T. Mayne, Director of the Center for Food Safety and Applied Nutrition, addressed concerns about infant formula along the food chain, speaking to manufacturers, packers, distributors, exporters, importers and retailers.

“FDA is sharing this information with you with the expectation that you will act to mitigate potential food safety risks in powdered infant formula in accordance with FDA regulations while further striving to improve operations, especially given the critical nature of these products,” a letter from the FDA leaders states.

“. . . The FDA has reviewed conditions during recent inspections of powdered infant formula manufacturers, including routine surveillance inspections, for-cause inspections to follow up on consumer complaints and other interactions with manufacturers.”

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Posted in Cronobacter sakazakii, FDA, food bourne outbreak, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Safety Management, Food Safety Regulations, food safety training, foodborne outbreak, foodbourne outbreak, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, outbreak

Research – Modeling the Growth of Six Listeria monocytogenes Strains in Smoked Salmon Pâté

Posted on March 12, 2023 by | Leave a comment

MDPI

Abstract

In this study, the growth of six L. monocytogenes strains isolated from different fish products was quantified and modeled in smoked salmon pâté at a temperature ranging from 2 to 20 °C. The experimental data obtained for each strain was fitted to the primary growth model of Baranyi and Roberts to estimate the following kinetic parameters: lag phase (λ), maximum specific growth rate (μmax), and maximum cell density (Nmax). Then, the effect of storage temperature on the obtained μmax values was modeled by the Ratkowsky secondary model. In general, the six L. monocytogenes strains showed rapid growth in salmon pâté at all storage temperatures, with a relatively short lag phase λ, even at 2 °C. The growth behavior among the tested strains was similar at the same storage temperature, although significant differences were found for the parameters λ and μmax. Besides, the growth variations among the strains did not follow a regular pattern. The estimated secondary model parameter Tmin ranged from −4.25 to −3.19 °C. This study provides accurate predictive models for the growth of L. monocytogenes in fish pâtés that can be used in shelf life and microbial risk assessment studies. In addition, the models generated in this work can be implemented in predictive modeling tools and repositories that can be reliably and easily used by the fish industry and end-users to establish measures aimed at controlling the growth of L. monocytogenes in fish-based pâtés.

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

Research – In-Package Atmospheric Cold Plasma Treatment and Storage Effects on Membrane Integrity, Oxidative Stress, and Esterase Activity of Listeria monocytogenes

Posted on March 12, 2023 by | Leave a comment

MDPI

kswfoodworld

Abstract

Atmospheric cold plasma (ACP) treatment can reduce bacterial pathogens in foods. Additional reduction in bacterial cells during storage after ACP treatment was previously reported. The underlying mechanisms of bacterial inactivation during ACP treatment and post-treatment storage need to be understood. This study investigated the changes in the morpho-physiological status of Listeria monocytogenes on ham surfaces after post-ACP-treatment storage of 1 h, 24 h, and 7 days at 4 °C. The membrane integrity, intracellular oxidative stress, and esterase activity of L. monocytogenes were evaluated by flow cytometry. L. monocytogenes cells were under high oxidative stress conditions with slightly permeabilized membranes after 1 h of post-ACP-treatment storage according to the flow cytometry data. During the extended storage of 24 h, the percentage of cells with a slightly permeabilized membrane increased; subsequently, the percentage of cells with intact membranes decreased. The percentage of L. monocytogenes cells with intact membranes decreased to <5% with a treatment time of 10 min and after 7 days of post-treatment storage. In addition, the percentage of L. monocytogenes cells under oxidation stress decreased to <1%, whereas the percentage of cells with completely permeabilized membranes increased to more than 90% for samples treated with ACP for 10 min and 7 days of post-treatment storage. With increased ACP treatment time, for 1 h stored samples, the percentage of cells with active esterase and slightly permeabilized membranes increased. However, during the extended post-treatment storage of 7 days, the percentage of cells with active esterase and slightly permeabilized membranes decreased to below 1%. At the same time, the percentage of cells with permeabilized membrane increased to more than 92% with an increase in ACP treatment time of 10 min. In conclusion, the higher inactivation after 24 h and 7 days post-ACP-treatment storage compared to 1 h stored samples correlated with the loss of esterase activity and membrane integrity of L. monocytogenes cells.

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Posted in Cold Atmospheric Plasma, Cold Plasma, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

Research – Catalan Food Safety Agency – Quality criteria for drinking water used in the food industry

Posted on March 12, 2023 by | Leave a comment

ACSA

On January 12, 2023 , Royal Decree 3/2023  came into force, establishing the technical-sanitary criteria for the quality of drinking water , its control and supply .

This new Royal Decree represents a new, broad and complex regulatory framework to protect human health from any contamination of drinking water. Establishes the technical-sanitary criteria and the quality control of drinking water throughout the supply chain, from catchment water bodies to the user’s tap, with the aim of guaranteeing that drinking water is healthy and clean.

It also specifically establishes the quality criteria for drinking water used in the food industry (CHAPTER VI Water quality in the food company) :

  • It establishes the quality criteria, as well as the parameters and parametric values ​​of the water used for the manufacture, preparation or treatment of food, as well as for washing materials intended for contact with food.
  • The food company will be responsible for the quality of the water from the point of delivery to the connection or in the case of supply in tanks or mobile tanks, of all the phases that it carries out and that, as such, are described in the self-control systems based on in the principles of Hazard Analysis and Critical Control Points (HACCP).
  • The operator of the food company must ensure the quality of the drinking water used, through a sampling plan, different types of analysis and controls, which will be included in their self-control systems based on the HACCP principles. 

This regulation partially transposes Directive (EU) 2020/2184 in Spain  ,  relating to the quality of water intended for human consumption  and repeals Royal Decree 140/2003,  which establishes the sanitary criteria for the quality of drinking water .

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Water, water microbiology, Water Safety

Research – Using TRIS-Buffered Plasma-Activated Water to Reduce Pathogenic Microorganisms on Poultry Carcasses with Evaluation of Physicochemical and Sensory Parameters

Posted on March 11, 2023 by | Leave a comment

MDPI

Abstract

Foodborne diseases are mainly caused by the contamination of meat or meat products with pathogenic microorganisms. In this study, we first investigated the in vitro application of TRIS-buffered plasma-activated water (Tb-PAW) on Campylobacter (C.) jejuni and Escherichia (E.) coli, with a reduction of approx. 4.20 ± 0.68 and 5.12 ± 0.46 log10 CFU/mL. Furthermore, chicken and duck thighs (inoculated with C. jejuni or E. coli) and breasts (with natural microflora) with skin were sprayed with Tb-PAW. Samples were packed under a modified atmosphere and stored at 4 °C for 0, 7, and 14 days. The Tb-PAW could reduce C. jejuni on days 7 and 14 (chicken) and E. coli on day 14 (duck) significantly. In chicken, there were no significant differences in sensory, pH-value, color, and antioxidant activity, but %OxyMb levels decreased, whereas %MetMb and %DeoMb increased. In duck, we observed slight differences in pH-value, color, and myoglobin redox forms for the Tb-PAW, which were not perceived by the sensory test persons. With only slight differences in product quality, its application as a spray treatment may be a useful method to reduce C. jejuni and E. coli on chicken and duck carcasses.

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Posted in Antimicrobials, Campylobacter, Decontamination Microbial, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

Research – Pathogen Reduction Monitoring Program for Salmonella and Campylobacter for raw poultry

Posted on March 11, 2023 by | Leave a comment

CFIA

There is a significant burden of illness in Canada from foodborne salmonellosis and campylobacteriosis. Both epidemiological evidence end expert opinion recognize poultry and poultry derived products as an important source of these illnesses.

Salmonella and Campylobacter are known to occur naturally in live poultry and contamination may occur at any stage of the farm-to fork production. Accordingly, food businesses that slaughter poultry or process poultry products need to consider Salmonella and Campylobacter as hazards of concern to their products and implement control measures throughout their production process to mitigate risks. Food businesses can verify the efficacy of their control measures, such as sanitary dressing procedures and antimicrobial interventions by implementing the PRMP.

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Posted in Campylobacter, campylobacter coli, Campylobacter jejuni, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Salmonella, Salmonella in Chicken

USA – 300 passengers and crew fall ill on Ruby Princess cruise from Texas – Norovirus?

Posted on March 10, 2023 by | Leave a comment

Washington Post

More than 300 passengers and crew on the Ruby Princess contracted a gastrointestinal illness causing vomiting and diarrhea, the Centers for Disease Control and Prevention said this week.

The Princess Cruises voyage carrying about 4,000 people ran from Feb. 26 to Sunday in the western Caribbean and docked in Galveston, Tex.

While the CDC has not listed a specific virus, Princess Cruises said in a statement the cause was likely norovirus.

About 10 percent of the passengers and 3 percent of the crew onboard were sick, according to the CDC.

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Posted in food bourne outbreak, Food Illness, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Illness, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Norovirus, outbreak