Category Archives: Microbiological Risk Assessment

Research – Seafood safety and food‐borne zoonoses from fish

EFSA

Parasitic nematodes of the genus Anisakis are the causative agent of anisakiosis, an important fish‐borne zoonosis. Humans are infected through consumption of raw or undercooked fish, contaminated with the parasite. Infection can result in both gastrointestinal and allergic symptoms. There are few reports of anisakiosis in Portugal, but evidence of Anisakis allergy exists, indicating that exposure is occurring in the population. The European Food Risk Assessment Fellowship Programme (EU‐FORA) work programme, entitled: ‘Food safety of fish and zoonoses: fish consumption and microbiological risk assessment and perception, from fisherman to final consumers in Portugal’ was hosted by the Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), in Porto, Portugal. It aimed to gather information on risk perception and attitudes in the Portuguese population to contamination of fish with Anisakis spp. and on their knowledge of methods to prevent infection. In addition, it aimed to examine the risk of anisakiosis in the Portuguese population.

Research – Evaluation of Potential for Butyl and Heptyl Para-Hydroxybenzoate Enhancement of Thermal Inactivation of Cronobacter sakazakii during Rehydration of Powdered Infant Powdered Infant Formula and Non-Fat Dry Milk.

Journal of Food Protection

Prior studies have demonstrated that parabens enhanced the thermal inactivation of foodborne pathogens including Cronobacter sakazakii , Salmonella enterica serotype Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes in model systems. However, there have been few studies looking at this phenomenon in actual food systems. The current study evaluated the potential enhancement of thermal inactivation of C. sakazakii by butyl para-hydroxybenzoate (BPB) in powdered infant formula (PIF) and non-fat dry milk (NFDM) before and after rehydration. When PIF was rehydrated with water at designated temperatures (65 – 80 ºC) in baby bottles, BPB did not enhance thermal inactivation. Rehydrated NFDM and lactose solutions with BPB were inoculated and heated at 58 ºC, BPB enhancement of thermal inactivation was negatively associated with NFDM levels in a dose-dependent manner, whereas presence of lactose retained thermal enhancement regardless of its concentration, suggesting an interaction between proteins and BPB. Fluorescence tests further indicated an interaction between BPB and the proteins in PIF and NFDM. Inoculated dry NFDM with and without BPB stored at 24 ºC and 55 ºC for 14 days did not substantially enhance inactivation in the dry state. This study suggests that BPB is not likely to enhance mild thermal inactivation treatments in foods that have appreciable amounts of protein.

Research – Comparison of Selected Phenotypic Features of Persistent and Sporadic Strains of Listeria monocytogenes Sampled from Fish Processing Plants

MDPI

(1) Background: The main source of transmission of Listeria monocytogenes is contaminated food, e.g., fish and meat products and raw fruit and vegetables. The bacteria can remain for 13 years on machines in food processing plants, including fish plants.

(2) Methods: A total of 720 swabs were collected from a salmon filleting line. The research material consisted of 62 (8.6%) L. monocytogenes isolates. Pulsed Field Gel Electrophoresis (PFGE) allowed detecting a pool of persistent strains. All persistent strains (n = 6) and a parallel group of strains collected sporadically (n = 6) were characterized by their ability to invade HT-29 cells, biofilm formation ability, and minimum bactericidal concentrations (MBC) of selected disinfectants.

(3) Results: Among the obtained isolates, 38 genetically different strains were found, including 6 (15.8%) persistent strains. The serogroup 1/2a-3a represented 28 strains (73.7%), including the persistent ones. There were no significant differences in invasiveness between the persistent and sporadic strains. The persistent strains tolerated higher concentrations of the tested disinfectants, except for iodine-based compounds. The persistent strains initiated the biofilm formation process faster and formed it more intensively.

(4) Conclusions: The presence of persistent strains in the food processing environment is a great challenge for producers to ensure consumer safety. This study attempts to elucidate the phenotypic characteristics of persistent L. monocytogenes strains. View Full-Text

Research – A risk assessment model for Salmonella spp. in swine carcasses

EFSA

Salmonellosis is one of the most important food‐borne outbreaks that occurs in the EU/EEA. From the first production stages at slaughter, meat is susceptible to spoilage and can be a substrate for the pathogenic microorganisms growth. Among the pathogens, the presence of Salmonella is mainly due to mishandling during the evisceration stage. For the year 2019, according to the collected data from MSs, on the 17.9% of all food‐borne outbursts, the presence Salmonella was confirmed. Pork meat is considered as one of the four most commonly reported foods in cases of salmonellosis. For the training purposes of this project, Salmonella isolation and identification along with RA for carcass contamination, was performed. Pig carcasses were sampled using the non‐destructive technique. The sampling took place post dressing and before the stage of chilling. For the Salmonella detection, a three phases process was performed (pre‐enrichment, enrichment, isolation). A total of 757 samples were collected, 19 were found to be positive for Salmonella. The most common was found to be Salmonella Derby, which was identified eight times. The main objective of the project was to determine the prevalence of Salmonella spp. in swine carcasses. Moreover, certain parameters were evaluated in terms of their influence on the prevalence of Salmonella. A stochastic simulation model was developed in Microsoft Office Excel 2019 by using the add‐in @Risk v.8.1. The prevalence was estimated to be 2.6%. For the pigs sampled, the average value of the distance from farm to slaughterhouse was 200.92 km. Additionally, the average weight of the carcasses was 127.97 kg. The prevalence of Salmonella between the samples that came from farms with a distance above the average, was higher by 1.7 units, while the prevalence for the samples with weight above the average was higher by 0.2 units. According to the stochastic model, it is specified that the prevalence is higher with greater distance, and there is an 8.1% probability the prevalence will exceed the legislation’s – hygiene criteria. In addition, the prevalence of Salmonella was shown to increase, as well in the case of samples from weightier animals, but to a lesser extent.

Norway Research – Outbreaks stable but illnesses down in 2021 

Food Safety News

The number of foodborne outbreaks in Norway has remained steady but fewer people were sick in 2021 compared to the year before.

A total of 25 foodborne outbreaks were announced this past year, which is on a par with 23 in 2020 but down compared to 46 in 2019 and 52 in 2018.

Overall, 327 people fell sick in the 25 outbreaks in 2021 with a range of three to 30 patients per outbreak. The 23 outbreaks in 2020 affected 495 people.

Data comes from a report that gives an overview of outbreaks and related illnesses reported to the Norwegian Institute of Public Health (FHI) in 2021.

Research – A Review of Essential Oils as Antimicrobials in Foods with Special Emphasis on Fresh Produce

Journal of Food Protection

Consumer safety concerns over established fresh produce washing methods, combined with demand for organic and clean label food, has led to the exploration of novel methods of produce sanitization. Essential oils (EOs), extracted from commonly found plants have potential as clean label sanitizers, as they are naturally derived and act as antimicrobials as well as antioxidants. In this review, the antimicrobial abilities of EOs are explored in the following categories: individually and in-combination, as emulsions, combined with existing chemical and physical preservation methods, incorporated into films and coatings, and in vapor phase. We examine combining EOs with one another, with EO components, with surfactants, or with other preservatives or preservation methods to increase sanitizing efficacy.  Components of major EOs are also identified, chemical mechanisms are discussed, and potential for antibacterial resistance and effect on organoleptic properties is examined. Studies reveal that EOs can serve as equivalent or better sanitizing agents than chlorine; nevertheless, concentrations must be kept low to avoid adverse sensory effects. For this reason, it is crucial that future studies address the maximum permissible EO concentrations, which do not negatively affect sensory properties.  This review should be beneficial to food scientists or industry personnel interested in sanitization and preservation of foods, including fresh produce with EOs.

Research – The Response and Survival Mechanisms of Staphylococcus aureus under High Salinity Stress in Salted Foods

MDPI

Staphylococcus aureus (S. aureus) has a strong tolerance to high salt stress. It is a major reason as to why the contamination of S. aureus in salted food cannot be eradicated. To elucidate its response and survival mechanisms, changes in the morphology, biofilm formation, virulence, transcriptome, and metabolome of S. aureus were investigated. IsaA positively regulates and participates in the formation of biofilm. Virulence was downregulated to reduce the depletion of nonessential cellular functions. Inositol phosphate metabolism was downregulated to reduce the conversion of functional molecules. The MtsABC transport system was downregulated to reduce ion transport and signaling. Aminoacyl-tRNA biosynthesis was upregulated to improve cellular homeostasis. The betaine biosynthesis pathway was upregulated to protect the active structure of proteins and nucleic acids. Within a 10% NaCl concentration, the L-proline content was upregulated to increase osmotic stability. In addition, 20 hub genes were identified through an interaction analysis. The findings provide theoretical support for the prevention and control of salt-tolerant bacteria in salted foods. View Full-Text

Research – Multistate Outbreak of Listeria monocytogenes Infections Linked to Fresh, Soft Hispanic-Style Cheese — United States, 2021

CDC

Summary

What is already known about this topic?

Listeriosis outbreaks are frequently associated with consumption of fresh, soft Hispanic-style cheeses.

What is added by this report?

In early 2021, a multistate outbreak of listeriosis involving 13 cases in four states occurred, resulting in 12 hospitalizations and one death. The outbreak was linked to Hispanic-style cheese within 19 days of cluster detection. Rapid food testing by regulatory agencies in response to the investigation identified the implicated cheese.

What are the implications for public health practice?

To prevent severe health outcomes among persons at increased risk for listeriosis, public health agencies should improve communications, including implementing new methods of dissemination to emphasize the risk from eating fresh, soft Hispanic-style cheeses, even those made with pasteurized milk. 

Listeriosis is a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes. An estimated 1,600 persons become ill with listeriosis each year, among whom approximately 260 die. Persons at higher risk for listeriosis include pregnant persons and their newborns, adults aged ≥65 years, and persons with weakened immune systems. Persons with invasive listeriosis usually report symptoms starting 1–4 weeks after eating food contaminated with L. monocytogenes; however, some persons who become infected have reported symptoms starting as late as 70 days after exposure or as early as the same day of exposure (1). On January 29, 2021, PulseNet, the national molecular subtyping surveillance network coordinated by CDC, identified a multistate cluster of three L. monocytogenes infections: two from Maryland and one from Connecticut (2). CDC, the Food and Drug Administration (FDA), and state and local partners began an investigation on February 1, 2021. A total of 13 outbreak-related cases were eventually identified from four states. All patients reported Hispanic ethnicity; 12 patients were hospitalized, and one died. Rapid food testing and record collection by regulatory agencies enabled investigators to identify a brand of queso fresco made with pasteurized milk as the likely source of the outbreak, leading to an initial product recall on February 19, 2021. Fresh, soft Hispanic-style cheeses made with pasteurized milk are a well-documented source of listeriosis outbreaks. These cheeses can be contaminated with L. monocytogenes unless stringent hygienic controls are implemented, and the processing environment is monitored for contamination (3). U.S. public health agencies should establish or improve communications, including new methods of disseminating information that also effectively reach Hispanic populations, to emphasize the risk from eating fresh, soft Hispanic-style cheeses, even those made with pasteurized milk.

USA – BEAM Dashboard

CDC

The BEAM (Bacteria, Enterics, Amoeba, and Mycotics) Dashboard is an interactive tool to access and visualize data from the System for Enteric Disease Response, Investigation, and Coordination (SEDRIC). The BEAM Dashboard provides timely data on pathogen trends and serotype details to inform work to prevent illnesses from food and animal contact. Currently, the dashboard focuses on data for Salmonella bacteria, but it will eventually include additional pathogens, antimicrobial resistance data, and epidemiologic data from outbreak investigations.

Frequently Asked Questions (FAQ)

For additional questions, please contact simso@cdc.gov.

Kenya – Aflatoxins link in Kenya cancer burden

Business Daily Africa

Known as a family of toxins produced by certain fungi, aflatoxins have been established to be highly harmful to human beings.

Of late they have also been linked to the high cases of cancer. The best-known one is Aspergillus flavus, that attacks crops such as maize, pulses and groundnuts while in the field and in storage when they are not dried and stored properly.

Aflatoxins also lower the body’s immunity and cause permanent and irreversible stunting in children. And in cases of acute poisoning, they can lead to instant death. But in cases of long-time exposure, they are known to provoke liver cancer.

A study conducted in February this year by James Kibugu, of the Kenya Agricultural and Livestock Research Organisation (Kalro) and four others shows that these poisonous chemicals are becoming a major burden on Kenya’s health care system.

But Kenya could reduce the cancer burden if food safety standards are strictly enforced.

Kibugu’s paper published in the African Journal of Food, Agriculture, Nutrition and Development notes that common cereals like maize and wheat have total aflatoxin levels higher than Kenyan, USA, and EU standards.