A Systematic Review of Beef Meat Quantitative Microbial Risk Assessment Models

Health risk assessment of Staphylococcus aureus and Salmonella from the consumption of street foods in Ethiopia

INTRODUCTION

Due to inadequate hygienic practices and improper handling, street foods may become contaminated, posing a significant risk for various foodborne diseases. This study aimed to determine the health risks to consumers from consuming street foods contaminated with Staphylococcus aureus and Salmonella.

METHOD

A cross-sectional study design was used from December 2022 to February 2023 on the street foods of Addis Ababa, Hawassa, Dire Dawa, and Jimma towns. A total of 525 street foods were taken from 175 street food vending stalls. A stratified sampling technique was used to select vending stalls. A questionnaire was used to collect the data which were analyzed via SPSS-25. Food samples were analyzed at the Ethiopian Public Health Institute food microbiology laboratory using the standard microbiological methods used for the isolation, enumeration, and identification of bacteria. A quantitative microbial risk assessment was used to assess and determine the risk of infection using a deterministic approach.

RESULT

The frequent, average, and occasional consumers of street foods were 26.9%, 52.6%, and 20.5% respectively. The prevalence of Staphylococcus aureus was 43.4% whereas 25.7% for Salmonella species. The risk of infection from S. aureus was higher than Salmonella. The mean annual risk of S aureus infection of consumers was 100%, 99%, and 93% for frequent, average, and occasional consumers respectively. A total of 32.6% of the sampled foods had greater than 104 CFU/g a colony count of Staphylococcus aureus whereas in 25.7% of the samples Salmonella exceeded the safety standards and made the food unfit for consumption.

CONCLUSION

The results highlighted the significant risk of infection with Staphylococcus aureus and Salmonella in Ethiopian street foods, and revealed that frequent consumption of street foods was associated with a high risk of infection. This urges improved hygiene practices to mitigate hazards and protect public health.

Distribution of multidrug-resistant Proteus mirabilis in poultry, livestock, fish, and the related environment: One Health heed

Background and Aim

The emergence of multidrug-resistant (MDR) Proteus mirabilis in food-producing animals and their associated environments is a growing public health concern. The indiscriminate use of antimicrobials in animal husbandry exacerbates resistance development, posing significant threats to food safety and sustainability. This study investigates the distribution, antibiotic resistance patterns, and virulence-associated genes (VAGs) of P. mirabilis isolated from poultry, livestock, fish, and their environments in Pakistan under a One Health perspective.

Materials and Methods

A total of 225 samples were collected from poultry (n = 100), livestock (n = 75), and aquatic sources (n = 50) from March 2023 to September 2024. Standard microbiological methods were employed for the isolation and identification of P. mirabilis. Polymerase chain reaction (PCR)-based detection of antibiotic resistance genes and VAGs was performed using specific primers. Antibiotic susceptibility was assessed through the disk diffusion method following Clinical and Laboratory Standards Institute 2022 guidelines. Statistical analyses, including analysis of variance and correlation models, were applied to assess the relationships between variables.

Results

P. mirabilis was detected in 28.44% (64/225) of the total samples, with the highest occurrence observed in poultry (38%), followed by livestock (22.67%) and aquatic sources (18%). Resistance to ampicillin (100%), chloramphenicol (82%), cefepime (75%), and ciprofloxacin (75%) was widespread. PCR analysis revealed a high occurrence of extended-spectrum beta-lactamase-producing P. mirabilis carrying bla CTX-M (49%), bla OXA (54%), and bla TEM (25.67%) genes. In addition, VAGs such as zapA (39.53%), ucaA (34.88%), and hpmA (32.55%) were frequently identified. The presence of MDR P. mirabilis in fish and related environments (18%) is alarming, highlighting potential zoonotic and foodborne transmission risks.

Conclusion

The study underscores the widespread distribution of MDR P. mirabilis in animal-based food sources, raising significant concerns regarding food safety and antimicrobial resistance. The findings reinforce the need for stringent monitoring and regulatory policies to mitigate MDR bacterial dissemination across the food supply chain. Future research should employ metagenomic approaches for comprehensive surveillance and risk assessment.

Cultivated meat microbiological safety considerations and practices

Cultivated meat, produced using cell culture technology, is an alternative to conventional meat production that avoids the risks from enteric pathogens associated with animal slaughter and processing. Cultivated meat therefore has significant theoretical microbiological safety advantages, though limited information is available to validate this. This review discusses sources and vectors of microbial contamination throughout cultivated meat production, introduces industry survey data to evaluate current industry practices for monitoring and mitigating these hazards, and highlights future research needs. Industry survey respondents reported an average microbiological contamination batch failure rate of 11.2%. The most common vectors were related to personnel, equipment, and the production environment, while the most commonly reported type of microbiological contaminant was bacteria. These will likely remain prominent vectors and source organisms in commercial-scale production but can be addressed by a modified combination of existing commercial food and biopharmaceutical production safety systems such as Hazard Analysis and Critical Control Points (HACCP), Good Manufacturing Practices (GMP), and Good Cell Culture Practice (GCCP). As the sector matures and embeds these and other safety management systems, microbiological contamination issues should be surmountable. Data are also included to investigate whether the limited microbiome of cultivated products poses a novel food safety risk. However, further studies are needed to assess the growth potential of microorganisms in different cultivated meat products, taking into account factors such as their composition, pH, water activity, and background microflora.

Innovative approaches to controlling Salmonella in the meat industry

Salmonella, a Gram-negative, rod-shaped bacterium from the Enterobacteriaceae family, is a significant cause of illnesses in humans and animals. It resides in the digestive tracts of livestock, poultry, and other warm-blooded animals and can contaminate various environments and foods through fecal matter. Salmonella enterica, the main species that affects humans, is widespread in cattle, pigs, and poultry. Despite efforts to control pathogens in meat systems, over 1.4 million human salmonellosis cases occur annually in the U.S., with serotypes S. enteritidis and S. typhimurium being predominant. Advances in meat processing have targeted pathogen reduction at multiple stages, but more innovative approaches are needed for substantial public health impact. This paper discusses current and future strategies to minimize Salmonella in the food supply. It emphasizes pre- and post-harvest Salmonella prevalence by biomapping it through the whole processing chain, focusing on beef and pork interventions such as probiotics. These interventions have shown promise in reducing pathogen loads in cattle manure and lymph nodes. Techniques such as microbiome, whole genome sequencing (WGS), and electron microscopy (EM) provide detailed insights into Salmonella's genetic and bacterial structural-morphological characteristics, aiding in the development of targeted interventions. Integrating rapid detection, biomapping, and enviromapping enhances pathogen tracking in meat production, reducing Salmonella prevalence and improving risk assessment and food safety. The advanced, current, and innovative techniques allow for timely identification, detailed spatial and quantitative data, and more effective interventions. This leads to safer food products and reduces foodborne illnesses.

Bacterial profile of pork from production to retail based on high-throughput sequencing

Pork is a common vehicle for foodborne pathogens, including Salmonella spp. and Yersinia enterocolitica. Cross-contamination can occur at any stage of the pork production chain, from farm to market. In the present study, high-throughput sequencing was used to characterize bacterial profiles and track their changes along the whole supply chain. Tracked meat samples (pig on the farm, carcass in the slaughterhouse, unprocessed carcass and processed meat in the processing plant, and fresh pork at the local retail stores) and their associated environmental samples (e.g., water, floor, feed, feces, and workers' gloves) were collected from sequential stages (n = 96) and subjected to 16S rRNA metataxonomic analyses. At the farm, a total of 652 genera and 146 exclusive genera were identified in animal and environmental samples (pig, drain, floor, fan, and feces). Based on beta diversity analysis, it was demonstrated that the microbial composition of animal samples collected at the same processing step is similar to that of environmental samples (e.g., drain, fan, feces, feed, floor, gloves, knives, tables, and water). All animal and environmental samples from the slaughterhouse were dominated by Acinetobacter (55.37 %). At the processing plant, belly meat and neck meat samples were dominated by Psychrobacter (55.49 %). At the retail level, key bacterial players, which are potential problematic bacteria and important members with a high relative abundance in the samples, included Acinetobacter (8.13 %), Pseudomonas (6.27 %), and Staphylococcus (2.13 %). In addition, the number of confirmed genera varied by more than twice that identified in the processing plant. Source tracking was performed to identify bacterial contamination routes in pork processing. Animal samples, including the processing plant's carcass, the pig from the farm, and the unwashed carcass from the slaughterhouse (77.45 %), along with the processing plant's gloves (5.71 %), were the primary bacterial sources in the final product. The present study provides in-depth knowledge about the bacterial players and contamination points within the pork production chain. Effective control measures are needed to control pathogens and major pollutants at each stage of pork production to improve food safety.

Distance and destination of retail meat alter multidrug resistant contamination in the United States food system

Antibiotic-resistant infections are a global concern, especially those caused by multidrug-resistant (MDR) bacteria, defined as those resistant to more than three drug classes. The animal agriculture industry contributes to the antimicrobial resistant foodborne illness burden via contaminated retail meat. In the United States, retail meat is shipped across the country. Therefore, understanding geospatial factors that influence MDR bacterial contamination is vital to protect consumers and inform interventions. Using data available from the United States Food and Drug Administration's National Antimicrobial Resistance Monitoring System (NARMS), we describe retail meat shipping distances using processor and retailer locations and investigated this distance as a risk factor for MDR bacteria meat contamination using log-binomial regression. Meat samples collected during 2012-2014 totaled 11,243, of which 4791 (42.61%) were contaminated with bacteria and 835 (17.43%) of those bacteria were MDR. All examined geospatial factors were associated with MDR bacteria meat contamination. After adjustment for year and meat type, we found higher prevalence of MDR contamination among meat processed in the south (relative adjusted prevalence ratio [aPR] 1.35; 95% CI 1.06-1.73 when compared to the next-highest region), sold in Maryland (aPR 1.12; 95% CI 0.95-1.32 when compared to the next-highest state), and shipped from 194 to 469 miles (aPR 1.59; 95% CI 1.31-1.94 when compared to meats that traveled < 194 miles). However, sensitivity analyses revealed that New York sold the meat with the highest prevalence of MDR Salmonella contamination (4.84%). In this secondary analysis of NARMS data, both geographic location where products were sold and the shipping distance were associated with microbial contamination on retail meat.

Screening, molecular identification, population diversity, and antibiotic susceptibility pattern of Actinomycetes species isolated from meat and meat products of slaughterhouses, restaurants, and meat stores of a developing country, Iran

Introduction

Actinomycetes can colonize surfaces of tools and equipment and can be transferred to meat and meat products during manufacture, processing, handling, and storage. Moreover, washing the meat does not eliminate the microorganisms; it only spreads them. As a result, these opportunistic pathogens can enter the human body and cause various infections. Therefore, the aim of the current study was to screen, identify, and determine the antibiotic susceptibility of Actinomycetes species from meat and meat products in the Markazi province of Iran.

Methods

A total of 60 meat and meat product samples, including minced meat, mutton, beef, chicken, hamburgers, and sausages, were collected from slaughterhouses, butchers, and restaurants in the Markazi province of Iran. The samples were analyzed using standard microbiological protocols for the isolation and characterization of Actinomycetes. PCR amplification of hsp65 and 16SrRNA genes and sequence analysis of 16SrRNA were used for genus and species identification. The minimum inhibitory concentrations (MICs) of antimicrobial agents were determined by the broth microdilution method and interpreted according to the CLSI guidelines.

Results

A total of 21 (35%) Actinomycetes isolates from 5 genera and 12 species were isolated from 60 samples. The most prevalent Actinomycetes were from the genus Mycobacterium, with six (28.6%) isolates (M. avium complex, M. terrae, M. smegmatis, and M. novocastrense), followed by the genus Rhodococcus with five (23.8%) isolates (R. equi and R. erythropolis), the genus Actinomyces with four (19.1%) isolates (A. ruminicola and A. viscosus), the genus Nocardia with four (19.1%) isolates (N. asiatica, N. seriolae, and N. niigatensis), and the genus Streptomyces with two (9.5%) isolates (S. albus). Chicken and sausage samples had the highest and lowest levels of contamination, with six and one isolates. Respectively, the results of drug susceptibility testing (DST) showed that all isolates were susceptible to Ofloxacin, Amikacin, Ciprofloxacin, and Levofloxacin, whereas all of them were resistant to Doxycycline and Rifampicin.

Discussion

The findings suggest that meat and meat products play an important role as a reservoir for the transmission of Actinomycetes to humans, thus causing life-threatening foodborne diseases such as gastrointestinal and cutaneous disorders. Therefore, it is essential to incorporate basic hygiene measures into the cycle of meat production to ensure food safety.

Comparison of coliform paper test and ATP bioluminescence assay for monitoring the disinfection of kitchen utensils in canteens of hebei, China

Background

Two common techniques used in canteen hygiene supervision, are the coliform paper assay, which is the standard method, and the adenosine triphosphate (ATP) bioluminescence method. The coliform paper assay requires the incubation of the sample, which is time-consuming and does not provide a real-time assessment. Meanwhile, the ATP bioluminescence assay can provide real-time kitchenware cleanliness data.

Objective

This study aimed to compare these two methods for evaluating the sanitary condition of kitchenware and explore whether the ATP bioluminescence assay can be used as a standard method in sanitary inspection.

Methods

In this study, the cluster random sampling method was used to sample kitchenware from six canteens in the Hebei province, China. Samples were, assessed through the coliform paper test and ATP bioluminescence assay.

Results

Kitchenware negative rates for the coliform paper method and the ATP test were 64.39% and 49.07%, respectively. The Escherichia coli positive detection rate grew steadily as the relative light units (RLU) value for the ATP technique increased. The kappa coefficient for the two methods was 0.549, indicating that the two methods yield relatively consistent results.

Conclusion

Although currently not considered a standard method, simply using ATP detection is advantageous for quick on-site detection in catering unit hygiene supervision.

Prevalence of Antimicrobial Resistance and Clonal Relationship in ESBL/AmpC-Producing Proteus mirabilis Isolated from Meat Products and Community-Acquired Urinary Tract Infection (UTI-CA) in Southern Brazil

The present study aimed to evaluate the prevalence of antimicrobial resistance and clonal relationships in Proteus mirabilis isolated from chicken meat, beef, pork, and community-acquired urinary tract infections (UTI-CA). Chicken meat isolates showed the highest multidrug resistance (MDR), followed by those from pork and UTI-CA, whereas beef had relatively few MDR strains. All sources had strains that carried blaCTX-M-65, whereas blaCTX-M-2 and blaCMY-2 were only detected in chicken meat and UTI-CA isolates. This indicates that chicken meat should be considered an important risk factor for the spread of P. mirabilis carrying ESBL and AmpC. Furthermore, ESBL/AmpC producing strains were resistant to a greater number of antimicrobials and possessed more resistance genes than non-producing strains. In addition, the antimicrobial resistance genes qnrD, aac(6')-Ib-cr, sul1, sul2, fosA3, cmlA, and floR were also found. Molecular typing showed a genetic similarity between chicken meat and UTI-CA isolates, including some strains with 100% similarity, indicating that chicken can be a source of P. mirabilis causing UTI-CA. It was concluded that meat, especially chicken meat, can be an important source of dissemination of multidrug-resistant P. mirabilis in the community.

A Risk and Hazard Analysis Model for the Production Process of a New Meat Product Blended With Germinated Green Buckwheat and Food Safety Awareness

This study was specifically designed for a small-scale meat processing enterprise “DARIYA” to set up a specific HACCP plan for the new product (patties) made from mixed horsemeat with vegetable components developed in the Department of Technology of Food Production and Biotechnology, Shakarim University of Semey. Critical control points (CCPs) were identified and applied in the HACCP plan. The different hazards were detected at each processing step, whereas each CCP in the HACCP plan was identified and accompanied with the appropriate significant hazard, critical limit, monitoring of the CCP, and corrective actions, confirming that the enterprise has fully employed the HACCP methodology and ISO 22000:2018. Our results indicate that during almost 1 year following the implementation of ISO 22000:2018, the coliform level of tested patties significantly dropped (p < 0.05) after 6 months of implementation (coliform count dropped from 4.4 MPN/g to 1.8 MPN/g). The rapid screening of the bacterial count, heavy metals, pesticide residue, and physical contamination levels also improved monitoring assertiveness, allowing them to deal with foreseeable issues linking to resources and guarantee product quality. Cesium-137 was recorded as 5.4 ± 2.9627 Bq/kg in horsemeat and 6.7 ± 2.7045 in poultry. The activity of cesium-137 did not exceed the MAC. This result discloses that prompt screening is the foremost and necessary step for small enterprises. According to this study, the “acceptance of raw materials” is the most important CCP, and their control, particularly in small-scale meat processing enterprises, can actually prevent many negative outcomes. The implementation of both standards improved food quality by declining the flaw rates for patties, and the number of flow inconsistencies needed for correction in the process also dropped significantly (p < 0.05), demonstrating that safety and quality points were improving. If the application of the HACCP plan were to continue over an extended period of time, the Food Safety Management System's (FSMS) benefits would be more substantial improvements to a greater number of items being monitored. The process of implementing HACCP principles and ISO 22000:2018 could be arduous but achievable enough to be used in small industries with significant outcomes.

Microbial Contamination and Public Health: An Overview

Food contamination with microbial agents can take place at any stage of the food chain, from farm to fork. For this reason, good hygienic and manufacturing practices must be followed along the entire food chain to prevent microbiological food contamination due to microbes which can cause high incidence of morbidity and mortality among consumers. Recent research have been focused on the implementation of innovative technologies for enhancing the quality and safety of food without compromising its organoleptic and nutritional characteristics. Studies should be addressed to the development of simple, less expensive, and fast tests for monitoring and controlling microbial food contamination, as well as to the development of new food manufacturing processes.

Review: On-farm and processing factors affecting bovine carcass and meat quality

This paper reviews the current state of knowledge on beef carcass and meat quality, with particular emphasis on on-farm and processing factors associated with its high and inconsistent variability. The diversity of livestock systems comes from the diversity of breeds (dairy or beef), ages and gender (bulls, steers, heifers, cull cows) used to produce either mainly beef or beef and milk. In addition, there are factors linked to farming practices (including diet, especially grazing) which significantly influence the sensory, nutritional, technological and extrinsic (such as image) quality attributes of meat. These can become factors of positive differentiation when controlled by the application and certification of technical specifications. Finally, preslaughter (such as stress), slaughter (such as the chilling and hanging method of carcasses) and postslaughter (such as ageing, packaging and cooking) conditions have a strong influence on the microbiological, sensory, technological and image quality attributes of beef. In this review, potential synergisms or antagonisms between the different quality attributes are highlighted. For example, finishing cattle on grass, compared to indoor fattening on a high concentrate diet, has the advantage of producing leaner meat with a higher proportion of omega-3 fatty acids while exhibiting superior oxidative stability, but with the consequence of a darker meat colour and lower productivity, as well as higher seasonality and land surface requirements. Moreover, the control of on-farm factors is often guided by productivity (growth rate, feed conversion ratio) and carcass quality attributes (weight, conformation and fatness). Genetic selection has often been oriented in this direction, without taking other quality attributes into account. Finally, the interactions between all these factors (and especially between on-farm and slaughter or processing factors) are not considered in the quality grading schemes in European countries. This means that positive efforts at farm level may be mitigated or even eliminated by poor slaughtering or processing conditions. All these considerations explain why between-animal variability in quality can be high, even when animals come from the same farming system. The ability to predict the sensory and nutritional properties of meat according to production factors has become a major objective of the supply chain.

Engineering modeling frameworks for microbial food safety at various scales

The landscape of mathematical model-based understanding of microbial food safety is wide and deep, covering interdisciplinary fields of food science, microbiology, physics, and engineering. With rapidly growing interest in such model-based approaches that increasingly include more fundamental mechanisms of microbial processes, there is a need to build a general framework that steers this evolutionary process by synthesizing literature spread over many disciplines. The framework proposed here shows four interconnected, complementary levels of microbial food processes covering sub-cellular scale, microbial population scale, food scale, and human population scale (risk). A continuum of completely mechanistic to completely empirical models, widely-used and emerging, are integrated into the framework; well-known predictive microbiology modeling being a part of this spectrum. The framework emphasizes fundamentals-based approaches that should get enriched over time, such as the basic building blocks of microbial population scale processes (attachment, migration, growth, death/inactivation and communication) and of food processes (e.g., heat and moisture transfer). A spectrum of models are included, for example, microbial population modeling covers traditional predictive microbiology models to individual-based models and cellular automata. The models are shown in sufficient quantitative detail to make obvious their coupling, or their integration over various levels. Guidelines to combine sub-processes over various spatial and time scales into a complete interdisciplinary and multiphysics model (i.e., a system) are provided, covering microbial growth/inactivation/transport and physical processes such as fluid flow and heat transfer. As food safety becomes increasingly predictive at various scales, this synthesis should provide its roadmap. This big picture and framework should be futuristic in driving novel research and educational approaches.

Bacterial quality and safety of raw beef: A comparison between Finland and Nigeria

Beef can easily be contaminated with bacteria during the meat production chain. In this work, we studied the contamination levels of mesophilic aerobic bacteria (MAB) and thermotolerant coliform bacteria (TCB) on raw beef surfaces from small shops in Helsinki, Finland and meat markets in Benin City, Nigeria. We also investigated the prevalence of Salmonella, Campylobacter, Yersinia, Shiga toxin-producing Escherichia coli (STEC), Listeria, and cephalosporin-resistant E. coli (CREC). In total, one hundred unpacked raw beef samples from Finland and Nigeria were collected in 2019. The median MAB and TCB counts were significantly (P < 0.001) higher on beef from Nigeria than from Finland. The median MAB and TCB counts in Nigeria were 7.5 and 4.0 log₁₀ cfu/cm², respectively, and 6.5 and 2.8 log₁₀ cfu/cm² in Finland, respectively. Most (94%) Nigerian samples were unacceptable according to limits set by the EU. Beef samples from meat markets in Benin City were significantly (P < 0.05) more frequently contaminated with Salmonella, STEC, and CREC than beef samples from small shops in Helsinki. Salmonella, STEC, and CREC were isolated from 30, 36, and 96% of Nigerian samples, respectively, and from <2, 12, and 2% of Finnish samples, respectively. Our study demonstrates a significant difference between the bacterial contaminations of raw beef in Nigeria and Finland, along with a possible misuse of cephalosporins in animal husbandry in Nigeria.

Taking a lesson from the COVID-19 pandemic: Preventing the future outbreaks of viral zoonoses through a multi-faceted approach

The pandemic of the novel coronavirus disease 2019 (COVID-19) has caused a significant burden to healthcare systems, economic crisis, and public fears. It is also a lesson to be learned and a call-to-action to minimize the risk of future viral pandemics and their associated challenges. The present paper outlines selected measures (i.e., monitoring and identification of novel viral agents in animals, limitations to wildlife trade, decreasing hunting activities, changes to mink farming and meat production), the implementation of which would decrease such a risk. The role of viral surveillance systems and research exploring the virus strains associated with different animal hosts is emphasized along with the need for stricter wild trade regulations and changes to hunting activities. Finally, the paper suggests modifications to the meat production system, particularly through the introduction of cultured meat that would not only decrease the risk of exposure to novel human viral pathogens but also strengthen food security and decrease the environmental impacts of food production.

Quantitative microbial risk assessment and sensitivity analysis for workers exposed to pathogenic bacterial bioaerosols under various aeration modes in two wastewater treatment plants

Wastewater treatment plants (WWTPs) could emit a large amount of bioaerosols containing pathogenic bacteria. Assessing the health risks of exposure to these bioaerosols by using quantitative microbial risk assessment (QMRA) is important to protect workers in WWTPs. However, the relative impacts of the stochastic input variables on the health risks determined in QMRA remain vague. Hence, this study performed a Monte Carlo simulation-based QMRA case study for workers exposing to S. aureus or E. coli bioaerosols and a sensitivity analysis in two WWTPs with various aeration modes. Results showed that when workers equipped without personal protective equipment (PPE) were exposed to S. aureus or E. coli bioaerosol in the two WWTPs, the annual probability of infection considerably exceeded the U.S. EPA benchmark (≤10E-4 pppy), and the disease burden did not satisfy the WHO benchmark (≤10E-6 DALYs pppy) (except exposure to E. coli bioaerosol for disease health risk burden). Nevertheless, the use of PPE effectively reduced the annual infection health risk to an acceptable level and converted the disease health risk burden to a highly acceptable level. Referring to the sensitivity analysis, the contribution of mechanical aeration modes to the variability of the health risks was absolutely dominated in the WWTPs. On the aeration mode that showed high exposure concentration, the three input exposure parameters (exposure time, aerosol ingestion rate, and breathing rate) had a great impact on health risks. The health risks were also prone to being highly influenced by the various choices of the dose-response model and related parameters. Current research systematically delivered new data and a novel perspective on the sensitivity analysis of QMRA. Then, management decisions could be executed by authorities on the basis of the results of this sensitivity analysis to reduce related occupational health risks of workers in WWTPs.

Antimicrobial Blue Light versus Pathogenic Bacteria: Mechanism, Application in the Food Industry, Hurdle Technologies and Potential Resistance

Blue light primarily exhibits antimicrobial activity through the activation of endogenous photosensitizers, which leads to the formation of reactive oxygen species that attack components of bacterial cells. Current data show that blue light is innocuous on the skin, but may inflict photo-damage to the eyes. Laboratory measurements indicate that antimicrobial blue light has minimal effects on the sensorial and nutritional properties of foods, although future research using human panels is required to ascertain these findings. Food properties also affect the efficacy of antimicrobial blue light, with attenuation or enhancement of the bactericidal activity observed in the presence of absorptive materials (for example, proteins on meats) or photosensitizers (for example, riboflavin in milk), respectively. Blue light can also be coupled with other treatments, such as polyphenols, essential oils and organic acids. While complete resistance to blue light has not been reported, isolated evidence suggests that bacterial tolerance to blue light may occur over time, especially through gene mutations, although at a slower rate than antibiotic resistance. Future studies can aim at characterizing the amount and type of intracellular photosensitizers across bacterial species and at assessing the oxygen-independent mechanism of blue light-for example, the inactivation of spoilage bacteria in vacuum-packed meats.

Microbial Decontamination of Beef Carcass Surfaces by Lactic Acid, Acetic Acid, and Trisodium Phosphate Sprays

The present study was undertaken to investigate the effect of lactic acid (LA), acetic acid, (AA) and trisodium phosphate (TSP) spray on the microbiological population of beef carcass surfaces slaughtered in a traditional abattoir in Zagazig, Egypt. Higher microbial populations were determined on the shoulder than on the thigh surfaces, and meat sampling by tissue excision technique yielded significantly higher (P < 0.01) microbial count than swabbing method. The application of LA (2%), AA (2%), and TSP (12%) sprays for 30 seconds significantly (P < 0.01) reduced the microbial population counts on the beef surfaces by 0.9 to 2.2 logs. A complete inhibition of enterococci growth was achieved by LA and AA sprays. In general, LA and AA sprays were more efficient as antimicrobial agents than the TSP spray. Among the studied organisms, enterococci were the most reducible bacteria by LA and AA, followed by Enterobacteriaceae and coliforms, while Staphylococcus aureus being the least. This study also indicated that microbial populations determined on the shoulder were higher than on the thigh surfaces, and meat sampling by tissue excision technique yielded significantly higher (P < 0.01) microbial count than swabbing method.