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Category Archives: Food Micro Blog
Research – Thermal inactivation of Salmonella enterica and nonpathogenic bacterial surrogates in wheat flour by baking in a household oven 
Research – Terpenes Combinations Inhibit Biofilm Formation in Staphyloccocus aureus by Interfering with Initial Adhesion
The biofilm is a conglomerate of cells surrounded by an extracellular matrix, which contributes to the persistence of infections. The difficulty in removing the biofilm drives the research for new therapeutic options. In this work, the effect of terpenes (−)-trans-Caryophyllene, (S)-cis-Verbenol, (S)-(−)-Limonene, (R)-(+)-Limonene, and Linalool was evaluated, individually and in combinations on bacterial growth, by assay with resazurin; the formation of biofilm, by assay with violet crystal; and the expression of associated genes, by real-time PCR, in two clinical isolates of Staphyloccocus aureus, ST30-t019 and ST5-t311, responsible for more than 90% of pediatric infections by this pathogen in Paraguay. All combinations of terpenes can inhibit biofilm formation in more than 50% without affecting bacterial growth. The most effective combination was (−)-trans-Caryophyllene and Linalool at a 500 μg/mL concentration for each, with an inhibition percentage of 88%. This combination decreased the expression levels of the sdrD, spa, agr, and hld genes associated with the initial cell adhesion stage and quorum sensing. At the same time, it increased the expression levels of the cap5B and cap5C genes related to the production of capsular polysaccharides. The combinations of compounds tested are promising alternatives to inhibit biofilm formation in S. aureus. View Full-Text
Posted in Biofilm, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Research, Staphylococcus aureus
Research – Prevalence, genomic characterization, and risk assessment of human pathogenic Vibrio species in seafood
Pathogenic Vibrio spp. are largely responsible for human diseases caused through consumption of contaminated seafood. The aim of this study was to determine the prevalence, population densities, species diversity and molecular characteristics of pathogenic Vibrio in various seafood commodities and its associated health risks. Samples of finfish and shellfish (oysters and sea urchins) were collected from different regions and analyzed for Vibrio using the Most Probable Number (MPN) technique. Genomic DNA of putative Vibrio isolates was analyzed by whole genome sequencing (WGS) for taxonomic identification and identification of genes responsible for virulence and antimicrobial resistance. The risk of vibrio-related illnesses due to the consumption of contaminated seafood was assessed using Risk Ranger. Population densities of presumptive Vibrio fell in the range of 2.6 – 4.4 Log MPN/g and correlated with seasonality, with the summer season favoring significantly (p < 0.05) higher Vibrio counts. A total of 15 Vibrio isolates were identified as V. alginolyticus (5), V . parahaemolyticus (6), V. harveyi (2) or V. diabolicus (2). Two of the six V. parahaemolyticus isolates (ST 2504 and ST 2505) originating from oysters were found to be either tdh + or trh + and thus considered a human pathogen due to elaboration of Thermostable Direct Hemolysin (TDH) or TDH-related hemolysin (TRH). In addition to virulence genes, the shellfish isolates also harbored genes encoding resistance to multiple antibiotics including tetracycline, penicillin, quinolone and beta-lactam antibiotics, thus arousing concern. The risk assessment exercise pointed to an estimated 21 annual cases of V. parahaemolyticus -associated gastroenteritis in the general population attributed to consumption of contaminated oysters. This study highlights not only the wide prevalence and diversity of Vibrio in seafood, but also the potential of certain strains to threaten public health.
Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Vibrio, Vibrio albensis, Vibrio alginolyticus, Vibrio cholera, vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificans, Vibrio vulnificus
Research – Listeria monocytogenes Pathogenesis: The Role of Stress Adaptation
Adaptive stress tolerance responses are the driving force behind the survival ability of Listeria monocytogenes in different environmental niches, within foods, and ultimately, the ability to cause human infections. Although the bacterial stress adaptive responses are primarily a necessity for survival in foods and the environment, some aspects of the stress responses are linked to bacterial pathogenesis. Food stress-induced adaptive tolerance responses to acid and osmotic stresses can protect the pathogen against similar stresses in the gastrointestinal tract (GIT) and, thus, directly aid its virulence potential. Moreover, once in the GIT, the reprogramming of gene expression from the stress survival-related genes to virulence-related genes allows L. monocytogenes to switch from an avirulent to a virulent state. This transition is controlled by two overlapping and interlinked transcriptional networks for general stress response (regulated by Sigma factor B, (SigB)) and virulence (regulated by the positive regulatory factor A (PrfA)). This review explores the current knowledge on the molecular basis of the connection between stress tolerance responses and the pathogenesis of L. monocytogenes. The review gives a detailed background on the currently known mechanisms of pathogenesis and stress adaptation. Furthermore, the paper looks at the current literature and theories on the overlaps and connections between the regulatory networks for SigB and PrfA.
Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Research
Research – Chinese Foodborne Botulism Outbreaks Have High Mortality Rate; Tofu, Beef Common Causes
A study published in China CDC Weekly provides insight into foodborne botulism outbreaks in China. Researchers conducted an epidemiological analysis for the years of 2004–2020, which revealed a high mortality rate for cases of foodborne botulism and informed recommendations for reducing such outbreaks in China.
In the epidemiological analysis, data was collected from 22 of 31 Chinese provincial-level administrative divisions (PLADs) of the National Foodborne Disease Outbreaks Surveillance system, as well as the China National Knowledge Infrastructure, Wanfang Data, and Chinese Science and Technique Journals. The number and proportion of foodborne botulism outbreaks, illnesses, and deaths by PLAD; food types associated with outbreaks; and contributing factors were observed.
In total, 80 foodborne botulism outbreaks occurred in China during 2004−2020, with 386 illnesses and 55 deaths; initial misdiagnosis occurred in 27.5 percent of botulism cases. Most outbreaks were reported between June and August, aside from a spike in cases in January. Of the 22 PLADs that reported foodborne botulism outbreaks, Xinjiang reported the largest number of outbreaks (20), followed by Qinghai (13). Home-cooked, traditionally processed stinky tofu and dried beef were the most common vehicles for Clostridium botulinum, linked to 51.25 percent of botulism cases. Improper processing and storage practices contributed to 77.5 percent of foodborne botulism outbreaks.
Based on the study’s findings, the researchers suggest the implementation of botulism prevention and food safety education for farmers and herders in Xinjiang and Qinghai. The researchers also stress the urgency of improving Chinese foodborne illness outbreak investigation.
Posted in Bacterial Toxin, Clostridium, Clostridium botulinum, food bourne outbreak, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Safety, Food Safety Alert, Food Safety Management, food safety training, Food Toxin, foodborne outbreak, foodbourne outbreak, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, outbreak
Research – Peroxyacetic Acid Effectiveness against Salmonella on Raw Poultry Parts is not Affected by Organic Matter
Organic matter (OM) accumulation is common in chill tanks used to decontaminate raw poultry parts during processing. Organic matter negatively affects the antimicrobial activity of chlorine-based compounds, but its effect on the antimicrobial effectiveness of peroxyacetic acid (PAA) on poultry meat has not been described. Therefore, this study evaluated the effect of OM on the efficacy of PAA solutions in simulated post-chill tanks to reduce Salmonella artificially inoculated onto chicken parts. Chicken thighs were inoculated with a five-strain cocktail of poultry-borne Salmonella enterica serovars at ca. 6 log10CFU/ml. Then, the thighs were immersed for 30 or 45 s in PAA solutions (500 or 1,000 ppm) with chicken slurry to simulate OM accumulation (0, 15 or 30 g/L). The thighs were rinsed with neutralizing buffered peptone water (100 ml) and rinsates were plated onto XLD agar. Experiments were performed in triplicate (3 thighs/treatment/replicate). Chemical oxygen demand (COD), total nitrogen (TN), and pH were measured as the water quality parameters of the PAA solutions before and after use. COD ranged from 2,905 mg/L in unused 500-ppm solutions without added OM to 6,290 mg/Lin used 1,000-ppm solutions with 30 g/L of OM. Initial TN was 42.5 ± 2.0 mg/L and 60.9 ± 8.3 mg/L for 15 and 30 g/L OM, which increased by 27 ± 17 mg/L after use. The pH of solutions ranged from 3.16 ± 0.14 to 3.42 ± 0.09 for the 1,000-ppm solutions and from 3.59 ± 0.06 to 3.96 ± 0.06 for the 500-ppm solutions. Mean Salmonella reductions were 0.9 ± 0.1 log10CFU/ml of rinsate for the 500-ppm PAA treatment and 1.1 ± 0.1 log10CFU/ml of rinsate for 1,000-ppm PAA treatment. Exposure time did not have a significant effect on the logarithmic reductions. There was no significant effect of OM concentration (p>0.05) on the reductions, indicating that the antimicrobial efficacy was not affected and that PAA solutions may continue to be reused as long as the PAA concentration is actively monitored.
Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Research, Salmonella, Salmonella in Chicken
Research – Investigating and Preventing Foodborne Outbreaks Linked to Raw Milk and Raw Milk Dairy Products
Foodborne disease outbreaks and cases linked to raw milk and raw milk dairy products continue to be a concern. Investigations of these outbreaks often represent unique challenges, such as patients who may not be willing to disclose the source of the raw milk or identifying appropriate samples to collect on potential source farms (do you know what “milk socks” are and where to find them?)
To learn more about raw milk and dairy products, how to investigate outbreaks linked to them, and how to help prevent these outbreaks, view the NY CoE webinar on “Investigating and preventing foodborne disease outbreaks linked to raw milk and raw milk dairy products”, presented by Dr. Martin Wiedmann from Cornell University on 6/2/2022. Following the presentation, a panel of individuals who have been involved with investigating raw milk outbreaks participated in a Q&A dialogue. Panelists included subject matter experts from the New York State Department of Health, New York State Department of Agriculture and Markets, Maine Department of Health and Human Services, and Pennsylvania Department of Public Health. The webinar was recorded and can be accessed on the NY CoE YouTube here.
Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Safety, Food Safety Management, food safety training, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk
Research – Dynamics of Salmonella enterica and antimicrobial resistance in the Brazilian poultry industry and global impacts on public health
Non-typhoidal Salmonella enterica is a common cause of diarrhoeal disease; in humans, consumption of contaminated poultry meat is believed to be a major source. Here we determine that S. enterica serovars Heidelberg and Minnesota were the most prevalent serovars in Brazilian poultry and in poultry products imported from Brazil into the UK. However, long-term surveillance data collected by the UK Health Security Agency showed no increase in the incidence of Salmonella Heidelberg or Salmonella Minnesota in human cases of clinical disease in the UK following the increase of these two serovars in Brazilian poultry. Salmonella Heidelberg and Salmonella Minnesota clades shared resistance to sulphonamides, tetracyclines and beta-lactams conferred by sul2, tetA and blaCMY-2 genes, not widely observed in other co-circulating serovars despite similar selection pressures. The sul2 and tetA genes were concomitantly carried on IncC plasmids, whereas blaCMY-2 was either co-located with the sul2 and tetA genes on IncC plasmids or independently on IncI1 plasmids. These findings suggest that introduction of the Salmonella Enteritidis vaccine, in addition to increasing antimicrobial use, could have resulted in replacement of salmonellae in Brazilian poultry flocks with serovars that are more drug resistant, but less associated with disease in humans in the UK.
Posted in Decontamination Microbial, Food Illness, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Foodborne Illness, Illness, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Research, Salmonella, Salmonella in Chicken
RASFF Alerts – Aflatoxin – Argentinian Groundnuts and Peanuts
Aflatoxins in Argentine groundnut kernels in the Netherlands
Aflatoxins in Argentine groundnut kernels in the Netherlands
Exceeding the MRL for aflatoxin B1 in peanuts from Argentina in the Netherlands, Poland and Switzerland
Aflatoxin B1 in groundnuts, unroasted from Argentina in the Netherlands
Aflatoxin in Groundnut from Argentina in the Netherlands
Aflatoxin in groundnuts from Argentina in the Netherlands
Aflatoxins in Groundnut from Argentina in the Netherlands
Aflatoxin in Groundnuts from Argentina in the Netherlands
Aflatoxins in groundnuts from Argentina in the Netherlands
Posted in Aflatoxin, Aflatoxin B1, Aspergillus Toxin, food contamination, food handler, Food Hazard, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Food Poisoning, food recall, Food Safety, Food Safety Alert, Food Safety Management, Food Testing, Food Toxin, Mold Toxin, Mould Toxin, Mycotoxin, RASFF
RASFF Alerts – Salmonella -Polish Chicken Products – Sesame Seeds – Polish Turkey Products – Pistachio Kernels – Tom Ka Khai Soup – Poultry Meat
Salmonella typhimurium in turkey meat from Poland in Belgium and Croatia
Presence of Salmonella spp. in Indian hulled sesame seeds from India in Greece
Salmonella spp. in pistachio kernels from Iran in Latvia and Germany
Salmonella in Tom Ka Khai Steamed soup from Belgium in the Netherlands
Salmonella Infantis and Escherichia coli in poultry meat (chicken quarter) from Ukraine in Poland and the Netherlands
Salmonella Enteritidis and Salmonella spp in chicken neck skin from Poland in the Czech Republic, Hungary, Lithuania, Netherlands, Uzbekistan
Posted in food contamination, food handler, Food Hazard, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Food Pathogen, food recall, Food Safety, Food Safety Alert, Food Safety Management, Food Testing, Polish Chicken Salmonella, RASFF, Salmonella, Salmonella in Chicken, Salmonella Poland, Salmonella Sesame Seeds
