Category Archives: Food Microbiology Research

Research – Microbiological Risk Assessment in Foods: Background and Tools, with a Focus on Risk Ranger

MDPI

Risk assessment is an important phase of the food production path; it is strictly related to the processing chain as a necessary step for safe foods. This paper represents a contribution to understanding what is and how risk assessment could be conducted; it aims to provide some information on the structure of risk assessment, the tools for its identification and measurement and the importance of risk assessment for correct communication. In this context, after a focus on the background and on some commonly used tools (Risk Ranger, FDA-iRisk, decision tree, among others), the paper describes how to perform risk assessment through three case studies: lettuce (for Listeria monocytogenes), chicken salad (for Escherichia coli), and fresh egg pasta (for Staphylococcus aureus) in the first step, and then a comparison of risk for chicken salad contaminated by different pathogens (E. coli O157:H7, Campylobacter spp. and Salmonella sp.). As a final step, a critical evaluation of Risk Ranger was carried out, pointing out its pros and cons.

Research – Evaluation of peroxyacetic acid, liquid buffered vinegar, and cultured dextrose fermentate as potential antimicrobial interventions for raw chicken livers

Wiley Online

This study aimed to evaluate the use of peroxyacetic acid (PAA), buffered vinegar (BV), and cultured dextrose fermentate (CDF) to reduce Salmonella on artificially inoculated raw chicken livers, one of the most consumed offal around the world. Samples were inoculated with a 5-strain cocktail of poultry-borne Salmonella to obtain 106 CFU/g and immersed for 90 s with agitation in one of the following treatments: distilled water (control), 450 ppm PAA, 2.0% (w/v) BV, or 1.5% (w/v) CDF, prior to storing at 4°C. Salmonella was enumerated on XLD agar and monitored for 14 days. Data were analyzed using analysis of covariance. After immersion, there was a significant Salmonella reduction (p < .05) with all treatments, including the control. PAA resulted in the greatest numerical reduction at 0.65 ± 0.12 log; however, there were no significant differences in the reductions among all other treatments (p > .05). After 14 days, higher numerical reductions were observed for PAA, but only when compared to CDF. Although similar reductions (p > .05) were noted after 14 days except for CDF, Salmonella counts were lowest in all timepoints when PAA was used. PAA and CDF inhibited the growth of aerobic bacteria until day 3 while BV inhibited the growth up to 7 days. Regarding objective color, chicken livers immersed in PAA became lighter, but the difference was not sustained over time. No differences were observed in redness or yellowness values across any treatments.

Research – Special Issue: Coffee, Fungi, Mycotoxins, and Climate Change

MDPI

Coffee is very lucrative and enjoyed by many. It is a major cash crop, especially for countries without many alternative sources of income. However, production is threatened by climate change, a phenomenon that is now universally accepted as occurring and represents a major threat to societies and industry worldwide. Paterson and Lima [1] expressed great concern in 2010 about the lack of methods to combat climate change. Thirteen years later, there has been little tangible action to reduce climate change, despite many warm words about what will be done “sometime in the future”.
It is apposite to consider what would be the effect of climate change on coffee, particularly in relation to spoilage fungi and the production of mycotoxins. Fungi already cause considerable damage to coffee and mycotoxins have highly significant consequences on human and animal health. The commodity can be rejected by authorities when the concentrations of ochratoxin A (OTA) are too high.
We were hoping for more than four papers on the subject, but were pleased that the quality was so high of those we did receive. Gratitude is extended to Naresh Magan’s group for contributing two papers [2,3], both of which present novel data. Akbar et al. [2] have already been cited 15 times (Scopus (18 February 2023)), indicating the high relevance of their work. The growth and OTA production of Aspergillus westerdijkiae were tested in relation to, for example, water activity, temperature and CO2 in media and beans. Interestingly, in green coffee-based media, OTA production was optimum at 0.98–0.95 aw and 30 °C. However, in roasted coffee-based media, very little OTA was produced. In stored green coffee beans, optimum OTA was produced at 0.95–0.97 aw/30 °C.
The objective of Akbar et al. [3] (five Scopus citations ((18 February 2023))) was to examine the effect of treatment of coffee beans with gaseous ozone (O3) for the control of ochratoxigenic fungi and OTA contamination during storage. The paper revealed that, inter alia, it is unlikely that fungi and the OTA contamination of stored coffee beans would be controlled even with high O3 concentrations under wetter conditions.
Our first review on the topic came from Brazil [4], which already has six citations (Scopus ((18 February 2023)). Brazil produces the most coffee globally and we were especially pleased to receive this paper. Temperatures in coffee-producing municipalities in Brazil have increased by about 0.25 °C per decade and annual precipitation has decreased. Therefore, the coffee sector will face serious challenges in the next few decades and the impacts of climate change directly affect coffee mycobiota. Aflatoxins may become dominant with climate change, promoting greater food insecurity in coffee production. Closer attention by authorities is fundamental to stimulate the displacement of areas currently apt for coffee production, that will deteriorate in the future to novel climate zones with suitable climates. This will ameliorate the scarcity of coffee on the world market in the future.
Adhikari et al. [5] (13 citations Scopus ((18 February 2023))) reviewed how (a) suitable areas for coffee cultivation and (b) the toxigenic fungal taxa belonging to AspergillusPenicillium, and Fusarium will be affected due to climate change. Studies predict that suitable coffee cultivation areas could drop by 50%. Increased temperatures will see an overall increase in mycotoxin production such as aflatoxins, particularly by A. flavus, which grows at higher temperatures. Information regarding climate change parameters and mycotoxin concentrations in real coffee samples is provided. Modelling of future changes in coffee cultivation is also required. Indications show that climate change will result in an increase in mycotoxin contamination.
The current author expresses his appreciation to all the authors of this Special Issue and trusts the papers will be of considerable use to workers in the field. He also hopes that very large advances in reducing climate change will occur in the next 13 years, unlike the previous 13.

Research – German data shows Listeria in fish is still a problem

Food Safety News

Smoked and graved salmon continues to pose a Listeria infection risk with evidence showing a large proportion of listeriosis cases are caused by these products, according to scientists in Germany.

In 2021 and 2022, there were 66 cases of listeriosis in 15 outbreaks, reported the Robert Koch Institute (RKI).

A total of 24 outbreaks of listeriosis across federal states with links to smoked or graved salmon products as the cause have been found since 2010.

Research – High Genetic Diversity and Virulence Potential in Bacillus cereus sensu lato Isolated from Milk and Cheeses in Apulia Region, Southern Italy

MDPI

Abstract

The Bacillus cereus group includes species that act as food-borne pathogens causing diarrheal and emetic symptoms. They are widely distributed and can be found in various foods. In this study, out of 550 samples of milk and cheeses, 139 (25.3%) were found to be contaminated by B. cereus sensu lato (s.l.). One isolate per positive sample was characterized by Multilocus Sequence Typing (MLST) and for the presence of ten virulence genes. Based on MLST, all isolates were classified into 73 different sequence types (STs), of which 12 isolates were assigned to new STs. Virulence genes detection revealed that 90% and 61% of the isolates harboured the nheABC and the hblCDA gene cluster, respectively. Ninety-four percent of the isolates harboured the enterotoxin genes entS and entFM; 8% of the isolates possessed the ces gene. Thirty-eight different genetic profiles were identified, suggesting a high genetic diversity. Our study clearly shows the widespread diffusion of potentially toxigenic isolates of B. cereus s.l. in milk and cheeses in the Apulia region highlighting the need to adopt GMP and HACCP procedures along every step of the milk and cheese production chain in order to reduce the public health risk linked to the consumption of foods contaminated by B. cereus s.l.

USA – FDA Warning Letter – Old Europe Cheese, Inc. – Listeria monocytogenes

FDA

Dear Mr. Navarro,

The United States Food and Drug Administration (FDA) inspected your ready-to-eat (RTE) soft and semi-soft cheese manufacturing facility, located at 1330 E. Empire Avenue, Benton Harbor, MI, from September 13, 2022 through October 6, 2022. The inspection, conducted jointly with the Michigan Department of Agriculture and Rural Development (MDARD), was initiated as part of a multistate outbreak of Listeria monocytogenes (L. monocytogenes) infections linked to RTE soft cheese products supplied by your facility. According to the Centers for Disease Control and Prevention (CDC), six (6) ill people from six (6) states were infected with the outbreak strain of L. monocytogenes. On September 30, 2022, your firm recalled all RTE Brie and Camembert Soft Cheese products because they had the potential of being contaminated with L. monocytogenes. On October 5, 2022 your firm expanded the recall to also include Baked Brie Cheeses. One (1) environmental swab isolate collected by FDA during our inspection of your manufacturing facility matched the clinical outbreak isolates, based on Whole Genome Sequencing (WGS) analysis. According to the CDC, epidemiologic, traceback, and laboratory data showed that cheese made by Old Europe Cheese, Inc. made people sick.

USA – FDA – Core Outbreak Table – Investigations of Foodborne Illness Outbreaks

FDA

Date
Posted
Ref Pathogen
or
Cause of
Illness
Product(s)
Linked to
Illnesses

(if any)
Total
Case
Count

Status
3/29/2023 1141 Salmonella Infantis Raw Flour See
CDC
Investigation
Notice
Active
3/8/2023 1144 Salmonella Hartford Not Yet
Identified
53 Active
3/1/2023 1143 Hepatitis A Virus Frozen Organic
Strawberries
See
Outbreak
Advisory
Active
2/15/2023 1123 Listeria
monocytogenes
Not Yet
Identified
See
CDC
Investigation
Notice
Active
11/9/2022 1127 Listeria
monocytogenes
Enoki
Mushrooms
See
Outbreak
Advisory
Active

UK – FSA and FSS share findings from the evaluation of the recall system

Food Safety News

An updated food recall system in the United Kingdom has improved the situation but there are still areas to develop and things to consider for the future, according to an evaluation.

In 2016 and 2017, the Food Standards Agency (FSA) and Food Standards Scotland (FSS) held a review to improve the way food is recalled. This resulted in changes to the withdrawals and recalls system, including new guidance, a revised point-of-sale notice template for shops, and additional training for food businesses.

RSM UK Consulting was commissioned by FSA and FSS in 2021 to evaluate the development of the new system. This included a desk review, interviews with those who worked on the updated system, case studies of real recalls, looking at hypothetical scenarios, and consumer focus groups.

Those who worked on the new traceability, withdrawals, and recalls guidance said it was an improvement on the old document. However, one concern was that smaller businesses have fewer resources to implement the new processes and understand the legalities behind them. Lack of resources was also discussed as a barrier by local authorities.

USA – Consumer Reports compiles a list of 10 ‘risky foods’ to watch out for

Food Safety News

Consumer Reports is out with a new analysis of what it describes as risky foods consumers should know about.

The list was compiled after the organization looked at data from 2017 through 2022. The researchers focused on widely consumed foods that had recalls during the study period. They did not include recalled food related to allergens or extraneous materials. The report ranked recalls based on how many people died or became ill, as well as how widespread the outbreaks were and how many times a food was recalled.

The 10 foods that made the list are:

  • Leafy greens
  • Deli cheese and meat
  • Ground beef
  • Onions
  • Turkey
  • Chicken
  • Papayas
  • Peaches
  • Cantaloupe
  • Flour

“We aren’t saying people need to avoid these foods entirely, said Brian Ronholm, director of food policy at Consumer Reports, who lead the analysis.

“After all, these foods are usually safe and many of them are in fact import parts of a healthy diet.” Instead, he says, the list underscores the “importance of following best food safety practices with all of your foods, including knowing how to track and respond to food recalls when they happen.”

Vanuatu: Dozens of ciguatera cases reported since the beginning of the year

Outbreak News Today

The Vanuatu Ministry of Health reports that from January 1 to March 19, 27 ciguatera fish poisoning cases were recorded, all were clinically diagnosed.

The cases were distributed as follows: Seventeen (17) cases from Efate, 6 cases from Maewo, 2 cases from Ambrym, 1 from Ambae, 1 from Pentecost and 1 from Santo.

No deaths have been recorded.

From the cases reported, 69% of the cases consumed reef fish – not specified, 16 consumed Snapper and 15% consumed grouper.

More than 400 species of fish, including barracuda, black grouper, blackfin snapper, cubera snapper, dog snapper, greater amberjack, hogfish, horse-eye jack, king mackerel, and yellowfin grouper have been implicated in this food borne illness that’s relatively common in several areas of the world.