Category Archives: Food Microbiology Research

Research – New publication about microbiological hazards in fresh fruits and vegetables

FAO

Fresh fruits and vegetables contaminated with foodborne pathogens (bacteria, viruses, protozoa, helminths, etc.) have resulted in numerous outbreaks of foodborne illness, made headlines and caused trade disruptions around the world. To better understand these hazards, and how to prevent and mitigate the risks, FAO and WHO convened a meeting of scientific experts to identify and evaluate commodity-specific interventions used to reduce the risk of microbiological hazards in fresh fruit and vegetable production – from primary production to post-harvest activities, transportation, point of sale and preparation for consumption. A new report is now available and provides guidance, taking into consideration the effectiveness, practicality and suitability of the various approaches used in fruit and vegetable safety.

Prevention and control of microbiological hazards in fresh fruits and vegetables – Part 4: Specific commodities, which is volume 44 in the FAO/WHO Microbiological Risk Assessment Series, is the report of the meeting convened by the Secretariat of the Joint FAO/WHO Expert Meetings on Microbiological Risk Assessment (JEMRA). It addresses four commodity groups:  leafy vegetables and herbs, berries and tropical fruits, melons and tree fruits, and seeded and root vegetables.

This assessment updates and expands previous JEMRA work on the safety of fruits and vegetables and supports work being conducted by the Codex Alimentarius Commission on the development of guidelines for the control of Shiga toxin-producing Escherichia coli (STEC) in leafy vegetables and in sprouts.

Download the report

Germany -Meat of wild game animals should become safer

BFR

European network aims to further reduce health risks

Game meat, including those of red deer, wild boar, or pheasant, is among the foods with the smallest ecological footprint. These animals grow up in the wild, feeding on what na-ture provides, which also means that they can be exposed to various environmental con-taminants. Furthermore, wild animals can serve as carriers of zoonotic pathogens. The Eu-ropean network ‘Safety in the Game Meat Chain’ that will be established over the next four years under the leadership of the German Federal Institute for Risk Assessment (BfR),and promotes the exchange of knowledge regarding the health risks associated with game meat obtained through hunting for consumers. ‘Our goal is to make this valuable animal-derived food as safe as possible both in Europe and worldwide,’ says BfR President Professor Dr.Dr. Andreas Hensel. ‘We aim to minimize both chemical and microbial risks as much as possi-ble.’ The growing network currently includes 29 countries, encompassing not only EU member states but also non-EU countries, including those in the Western Balkans, Turkey, the United Kingdom, the United States, New Zealand, and Australia.

Over a four-year period, the five working groups of the network will focus on hunting and processing, game meat trade networks and the supply chain, as well as various biological and chemical hazards. To accomplish this, research activities from national level will be compiled and evaluated. Stakeholder groups from academia, industry, governmental institutions, and final consumers will receive ongoing updates on the new findings.

A central aim of the network is direct collaboration with stakeholder groups to translate knowledge into actions along the entire production chain, “from forest to fork” . The focus lies not only on undesirable substances from the environment (environmental con-taminants), but also on preventing or reducing the input of heavy metals, especially lead, from hunting ammunition. The biological hazards range from parasites such as Trichinella larvae, which can be transmitted to humans through the consumption of game meat, all the way to bacterial zoonotic agents including Salmonella and verotoxigenic Escherichia coli (VTEC), as well as viruses like hepatitis E (HEV) in wild boars.

Risks of both chemical and microbial origin that may arise during processing and trade of game meat, potentially contaminating the end product, will also be assessed. The goal is to disseminate scientific knowledge gained through the network from various regions and to align long-term food safety standards across borders.

The network also aims to gather insights into different hunting and training practices as well as national legal regulations and standards on meat inspection and hygiene for game meat in each country. The safety standards for cross-border trade in wild products are intended to be enhanced and harmonized. Additionally, the network places emphasis on educating con-sumers about the risks associated with and safe handling of game meat. Ultimately, this can support the consumer’s confidence in game meat products.

‘Safety in the Game Meat Chain’ is founded by the European Cooperation in Science and Technology (COST).

Useful links

SafeGameMeat COST Action (CA22166):
https://www.cost.eu/actions/CA22166/

Further information from the BfR website on game meat (in German)

SALMONELLA MODULATES METABOLISM DURING GROWTH UNDER CONDITIONS THAT INDUCE EXPRESSION OF VIRULENCE GENES.

SBGR Web

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a facultative pathogen that uses complex mechanisms to invade and proliferate within mammalian host cells. To investigate possible contributions of metabolic processes to virulence in S. Typhimurium grown under conditions known to induce expression of virulence genes, we used a metabolomics-driven systems biology approach coupled with genome-scale modeling. First, we identified distinct metabolite profiles associated with bacteria grown in either rich or virulence-inducing media and report the most comprehensive coverage of the S. Typhimurium metabolome to date. Second, we applied an omics-informed genome-scale modeling analysis of the functional consequences of adaptive alterations in S. Typhimurium metabolism during growth under our conditions. Modeling efforts highlighted a decreased cellular capability to both produce and utilize intracellular amino acids during stationary phase culture in virulence conditions, despite significant abundance increases for these molecules as observed by our metabolomics measurements. Furthermore, analyses of omics data in the context of the metabolic model indicated rewiring of the metabolic network to support pathways associated with virulence. For example, cellular concentrations of polyamines were perturbed, as well as the predicted capacity for secretion and uptake.

Research – ‘Overlooked’ problem of bacteria in fast-food soda fountains. How risky is that drink?

USA Today

Scientists in Southern California are asking the kind of questions that make soda drinkers uneasy after a recent study that found fast-food soda fountains were serving up high levels of bacteria along with self-serve drinks.

Researchers from Loma Linda University found bacteria levels that surpassed U.S. Environmental Protection Agency regulations for drinking water at fast-food restaurants in the eastern Coachella Valley, where largely low-income, Latino farmworker families have struggled with accessing potable water.

The study, published in August in the journal Drinking Water, found more than 40% of water samples from fast-food soda fountains had coliforms present, an indicator of contamination. The study calls into question the sanitation and maintenance of water from soda fountains, which rely on government and manufacturer standards.

Research – Why Are Cantaloupes Prone to Salmonella Contamination?

Very Well Health

Cantaloupes could be contaminated with Salmonella while they’re growing, or during harvest and handling, according to Teresa Bergholz, PhD, an associate professor of food science and human nutrition at Michigan State University.

Melons are grown close to the ground, and it’s possible that cantaloupes are exposed to bacteria from soil, animals, or the water used for irrigation.

“The ‘netted’ surface of the cantaloupe can facilitate microbes attaching to the surface, and can make it more difficult to remove microbes once they are present,” Bergholz told Verywell in an email.

Bergholz added that contaminated cantaloupes could also come in contact with other cantaloupes during processing and spread the pathogen further.

Canada – Sunrise Farms brand Young Turkey with giblets recalled due to possible spoilage

Gov Canada

Summary

Product
Young Turkey with giblets
Issue
Food – Microbial Contamination – Non harmful (quality or spoilage)
What to do

Do not use, sell, serve or distribute the affected product.

Audience
Retail
Distribution
Alberta
British Columbia
Manitoba
Saskatchewan

Sunrise Farms brand Young Turkey with giblets recalled due to possible spoilage.

The recalled product has been sold in Alberta, British Columbia, Manitoba and Saskatchewan.

Research – Recent Trends in Active Packaging Using Nanotechnology to Inhibit Oxidation and Microbiological Growth in Muscle Foods

MDPI

Muscle foods are highly perishable products that require the use of additives to inhibit lipid and protein oxidation and/or the growth of spoilage and pathogenic microorganisms. The reduction or replacement of additives used in the food industry is a current trend that requires the support of active-packaging technology to overcome novel challenges in muscle-food preservation. Several nano-sized active substances incorporated in the polymeric matrix of muscle-food packaging were discussed (nanocarriers and nanoparticles of essential oils, metal oxide, extracts, enzymes, bioactive peptides, surfactants, and bacteriophages). In addition, the extension of the shelf life and the inhibitory effects of oxidation and microbial growth obtained during storage were also extensively revised. The use of active packaging in muscle foods to inhibit oxidation and microbial growth is an alternative in the development of clean-label meat and meat products. Although the studies presented serve as a basis for future research, it is important to emphasize the importance of carrying out detailed studies of the possible migration of potentially toxic additives, incorporated in active packaging developed for muscle foods under different storage conditions.

Research – Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of Resistance

MDPI

Abstract

Antimicrobial resistance is now commonly observed in bacterial isolates from multiple settings, compromising the efficacy of current antimicrobial agents. Therefore, there is an urgent requirement for efficacious novel antimicrobials to be used as therapeutics, prophylactically or as preservatives. One promising source of novel antimicrobial chemicals is phytochemicals, which are secondary metabolites produced by plants for numerous purposes, including antimicrobial defence. In this report, we compare the bioactivity of a range of phytochemical compounds, testing their ability to directly inhibit growth or to potentiate other antimicrobials against Salmonella enterica Typhimurium, Pseudomonas aeruginosaListeria monocytogenes, and Staphylococcus aureus. We found that nine compounds displayed consistent bioactivity either as direct antimicrobials or as potentiators. Thymol at 0.5 mg/mL showed the greatest antimicrobial effect and significantly reduced the growth of all species, reducing viable cell populations by 66.8%, 43.2%, 29.5%, and 70.2% against S. enterica Typhimurium, S. aureusP. aeruginosa, and L. monocytogenes, respectively. Selection of mutants with decreased susceptibility to thymol was possible for three of the pathogens, at a calculated rate of 3.77 × 10−8, and characterisation of S. enterica Typhimurium mutants showed a low-level MDR phenotype due to over-expression of the major efflux system AcrAB-TolC. These data show that phytochemicals can have strong antimicrobial activity, but emergence of resistance should be evaluated in any further development.

Research – Fate of Planktonic and Biofilm-Derived Listeria monocytogenes on Unwaxed Apples during Air and Controlled Atmosphere Storage

MDPI

Abstract

Multiple recalls and outbreaks involving Listeria monocytogenes-contaminated apples have been linked to the post-harvest packing environment where this pathogen can persist in biofilms. Therefore, this study assessed L. monocytogenes survival on apples as affected by harvest year, apple cultivar, storage atmosphere, and growth conditions. Unwaxed Gala, Granny Smith, and Honeycrisp apples were dip-inoculated in an 8-strain L. monocytogenes cocktail of planktonic- or biofilm-grown cells (~6.5 log CFU/mL), dried, and then examined for numbers of L. monocytogenes during air or controlled atmosphere (CA) (1.5% O2, 1.5% CO2) storage at 2 °C. After 90 days, air or CA storage yielded similar L. monocytogenes survival (p > 0.05), regardless of harvest year. Populations gradually decreased with L. monocytogenes quantifiable in most samples after 7 months. Apple cultivar significantly impacted L. monocytogenes survival (p < 0.05) during both harvest years with greater reductions (p < 0.05) seen on Gala compared to Granny Smith and Honeycrisp. Biofilm-derived cells survived longer (p < 0.05) on L. monocytogenes-inoculated Gala and Honeycrisp apples compared to cells grown planktonically. These findings should aid in the development of improved L. monocytogenes intervention strategies for apple growers and packers.

Research – Anti-Biofilm Activity of Laurel Essential Oil against Vibrio parahaemolyticus

MDPI

Abstract

Vibrio parahaemolyticus is a primary seafood-associated pathogen that could cause gastroenteritis. It can attach to various surfaces and form a biofilm, which poses serious threats to food safety. Hence, an effective strategy is urgently needed to control the biofilm formation of V. parahaemolyticus. Laurel essential oil (LEO) is used in food, pharmaceutical and other industries, and is commonly used as a flavoring agent and valuable spice in food industries. The potential antibiofilm effects of LEO against V. parahaemolyticus were examined in this study. LEO obviously reduced biofilm biomass at sub-inhibitory concentrations (SICs). It decreased the metabolic activity and viability of biofilm cells. Microscopic images and Raman spectrum indicted that LEO interfered with the structure and biochemical compositions of biofilms. Moreover, it also impaired swimming motility, decreased hydrophobicity, inhibited auto-aggregation and reduced attachment to different food-contact surfaces. RT-qPCR revealed that LEO significantly downregulated transcription levels of biofilm-associated genes of V. parahaemolyticus. These findings demonstrate that LEO could be potentially developed as an antibiofilm strategy to control V. parahaemolyticus biofilms in food industries.