Flash heating process for efficient meat preservation.

Maintaining food safety and quality is critical for public health and food security. Conventional food preservation methods, such as pasteurization and dehydration, often change the overall organoleptic quality of the food products. Herein, we demonstrate a method that affects only a thin surface layer of the food, using beef as a model. In this method, Joule heating is generated by applying high electric power to a carbon substrate in <1 s, which causes a transient increase of the substrate temperature to > ~2000 K. The beef surface in direct contact with the heating substrate is subjected to ultra-high temperature flash heating, leading to the formation of a microbe-inactivated, dehydrated layer of ~100 µm in thickness. Aerobic mesophilic bacteria, Enterobacteriaceae, yeast and mold on the treated samples are inactivated to a level below the detection limit and remained low during room temperature storage of 5 days. Meanwhile, the product quality, including visual appearance, texture, and nutrient level of the beef, remains mostly unchanged. In contrast, microorganisms grow rapidly on the untreated control samples, along with a rapid deterioration of the meat quality. This method might serve as a promising preservation technology for securing food safety and quality.

Raw meat-based diet for pets: a neglected source of human exposure to Salmonella and pathogenic Escherichia coli clones carrying mcr, Portugal, September 2019 to January 2020.

BackgroundThe pet industry is expanding worldwide, particularly raw meat-based diets (RMBDs). There are concerns regarding the safety of RMBDs, especially their potential to spread clinically relevant antibiotic-resistant bacteria or zoonotic pathogens.AimWe aimed to investigate whether dog food, including RMBD, commercially available in Portugal can be a source of Salmonella and/or other Enterobacteriaceae strains resistant to last-line antibiotics such as colistin.MethodsFifty-five samples from 25 brands (21 international ones) of various dog food types from 12 suppliers were screened by standard cultural methods between September 2019 and January 2020. Isolates were characterised by phenotypic and genotypic methods, including whole genome sequencing and comparative genomics.ResultsOnly RMBD batches were contaminated, with 10 of 14 containing polyclonal multidrug-resistant (MDR) Escherichia coli and one MDR Salmonella. One turkey-based sample contained MDR Salmonella serotype 1,4,[5],12:i:- ST34/cgST142761 with similarity to human clinical isolates occurring worldwide. This Salmonella exhibited typical antibiotic resistance (bla TEM + strA-strB + sul2 + tet(B)) and metal tolerance profiles (pco + sil + ars) associated with the European epidemic clone. Two samples (turkey/veal) carried globally dispersed MDR E. coli (ST3997-complexST10/cgST95899 and ST297/cgST138377) with colistin resistance (minimum inhibitory concentration: 4 mg/L) and mcr-1 gene on IncX4 plasmids, which were identical to other IncX4 circulating worldwide.ConclusionSome RMBDs from European brands available in Portugal can be a vehicle for clinically relevant MDR Salmonella and pathogenic E. coli clones carrying genes encoding resistance to the last-line antibiotic colistin. Proactive actions within the One Health context, spanning regulatory, pet-food industry and consumer levels, are needed to mitigate these public health risks.

Apple cider vinegar exhibits promising antibiofilm activity against multidrug-resistant Bacillus cereus isolated from meat and their products.

Background: Bacillus cereus (B. cereus) biofilm is grown not only on medical devices but also on different substrata and is considered a potential hazard in the food industry. Quorum sensing plays a serious role in the synthesis of biofilm with its surrounding extracellular matrix enabling irreversible connection of the bacteria. Aim: The goal of the current investigation was to ascertain the prevalence, patterns of antimicrobial resistance, and capacity for B. cereus biofilm formation in meat and meat products in Egypt. Methods: In all, 150 meat and meat product samples were used in this study. For additional bacteriological analysis, the samples were moved to the Bacteriology Laboratory. Thereafter, the antimicrobial, antiquorum sensing, and antibiofilm potential of apple cider vinegar (ACV) on B. cereus were evaluated. Results: Out of 150 samples, 34 (22.67%) tested positive for B. cereus. According to tests for antimicrobial susceptibility, every B. cereus isolates tested positive for colistin and ampicillin but negative for ciprofloxacin and imipenem. The ability to form biofilms was present in all 12 multidrug-resistant B. cereus isolates (n = 12); of these, 6 (50%), 3 (25%), and 3 (25%) isolates were weak, moderate, and strong biofilm producers, respectively. It is noteworthy that the ACV demonstrated significant inhibitory effects on B. cereus isolates, with minimum inhibitory concentrations varying between 2 and 8 µg/ml. Furthermore, after exposing biofilm-producing B. cereus isolates to the minimum biofilm inhibitory concentrations 50 of 4 µg/ml, it demonstrated good antibiofilm activity (>50% reduction of biofilm formation). Strong biofilm producers had down-regulated biofilm genes (tasA and sipW) and their regulator (plcR) compared to the control group, according to reverse transcriptase quantitative polymerase chain reaction analysis. Conclusion: Our study is the first report, that spotlights the ACV activity against B. cereus biofilm and its consequence as a strong antibacterial and antibiofilm agent in the food industry and human health risk.

Prevalence and antibiogram of shigatoxinproducing E. coli in camel meat and offal.

Background: Camels are important animals in Egypt and other Arab countries on the basis of their economic value and ethnic culture. Escherichia coli is implicated in several gastrointestinal infections and outbreaks worldwide, especially in developing countries. It causes infections that might lead to death. Numerous biological activities, such as antioxidative, antibacterial, anti-diabetic, anti-mutagenic, anti-inflammatory, neuroprotective, and diuretic, are associated with coriander and coriander essential oils. Aim: This work targeted investigation of the prevalence, antibiogram, and occurrence of virulence genes of E. coli in camel meat liver and kidney. Besides, the anti-E. coli activity of coriander oil was further examined. Methods: Camel meat, liver, and kidneys were collected from local markets in Egypt. Isolation and identification of E. coli were performed. The antimicrobial susceptibility of the obtained E. coli isolates was screened using the disk diffusion assay. To detect the presence of virulence-associated genes (stx1, stx2, eaeA, and hylA gens), polymerase chain reaction was used. An experimental trial was done to investigate the anti-E. coli activity of coriander oil. Results: The obtained results revealed isolation of the following E. coli pathotypes: O17:H18, O128:H2, O119:H6, O103:H4, O145:H-, and O121:H7. The recovered E. coli isolates practiced multidrug resistance profiling with higher resistance toward Erythromycin, Nalidixic Acid, Clindamycin, and Ampicillin. However, the isolates were sensitive to Meropenem and cefoxitin. The recovered isolates had expressed different virulence attributes. Coriander oil of 2% could significantly reduce E. coli O128 count in camel meat by 65%. Conclusion: Therefore, strict hygienic measures are highly recommended during the processing of camel meat. The use of coriander oil during camel meat processing is highly recommended to reduce E. coli count.

Genomic characterization and probiotic potential assessment of an exopolysaccharide-producing strain Pediococcus pentosaceus LL-07 isolated from fermented meat.

BACKGROUND: The genomic information available for Pediococcus pentosaceus is primarily derived from fermented fruits and vegetables, with less information available from fermented meat. P. pentosaceus LL-07, a strain isolated from fermented meat, has the capability of producing exopolysaccharides (EPS). To assess the probiotic attributes of P. pentosaceus LL-07, we conducted whole-genome sequencing (WGS) using the PacBio SequelIIe and Illumina MiSeq platforms, followed by in vitro experiments to explore its probiotic potential. RESULTS: The genome size of P. pentosaceus LL-07 is 1,782,685 bp, comprising a circular chromosome and a circular plasmid. Our investigation revealed the absence of a CRISPR/Cas system. Sugar fermentation experiments demonstrated the characteristics of carbohydrate metabolism. P. pentosaceus LL-07 contains an EPS synthesis gene cluster consisting of 13 genes, which is different from the currently known gene cluster structure. NO genes associated with hemolysis or toxin synthesis were detected. Additionally, eighty-six genes related to antibiotic resistance were identified but not present in the prophage, transposon or plasmid. In vitro experiments demonstrated that P. pentosaceus LL-07 was comparable to the reference strain P. pentosaceus ATCC25745 in terms of tolerance to artificial digestive juice and bile, autoaggregation and antioxidation, and provided corresponding genomic evidence. CONCLUSION: This study confirmed the safety and probiotic properties of P. pentosaceus LL-07 via complete genome and phenotype analysis, supporting its characterization as a potential probiotic candidate.

Development of innovative active packaging films using gelatin/pullulan-based composites incorporated with cinnamon essential oil-loaded metal-organic frameworks for meat preservation.

This study aimed to investigate the effect of cinnamon essential oil (CEO)-loaded metal-organic frameworks (CEO@MOF) on the properties of gelatin/pullulan (Gel/Pull)-based composite films (Gel/Pull-based films). The incorporation of CEO@MOF into Gel/Pull-based films demonstrated significant antimicrobial activity against S. aureus, S. enterica, E. coli, and L. monocytogenes. Additionally, CEO@MOF integrated film exhibited a 98.16 % ABTS radical scavenging, with no significant change in the mechanical properties of the neat Gel/Pull film. The UV blocking efficiency of the composite films increased significantly from 81.38 to 99.56 % at 280 nm with the addition of 3 wt% CEO@MOF. Additionally, Gel/Pull/CEO@MOF films effectively extended the shelf life of meat preserved at 4 °C by reducing moisture loss by 3.35 %, maintaining the pH within the threshold limit (6.2), and inhibiting bacterial growth by 99.9 %. These results propose that CEO@MOF has significant potential as an effective additive in active packaging to improve shelf life and food safety.

Exploring the potential of hyperspectral imaging for microbial assessment of meat: A review.

Food safety is always of paramount importance globally due to the devasting social and economic effects of foodborne disease outbreaks. There is a high consumption rate of meat worldwide, making it an essential protein source in the human diet, hence its microbial safety is of great importance. The food industry stakeholders are always in search of methods that ensure safe food whilst maintaining food quality and excellent sensory attributes. Currently, there are several methods used in microbial food analysis, however, these methods are often time-consuming and do not allow real-time analysis. Considering the recent technological breakthroughs in artificial intelligence and machine learning, it raises the question of whether these advancements could be leveraged within the meat industry to improve turnaround time for microbial assessments. Hyperspectral imaging (HSI) is a highly prospective technology worth exploring for microbial analysis. The rapid, non-destructive method has the potential to be integrated into food production systems and allows foodborne pathogen detection in food samples, thus saving time. Although there has been a substantial increase in research on the utilisation of HSI in food applications over the past years, its use in the microbial assessment of meat is not yet optimal. This review aims to provide a basic understanding of the visible-near infrared HSI system, recent applications in the microbial assessment of meat products, challenges, and possible future applications.

High Salmonella load with serovar virchow dominance pose major public safety risk in postchill broiler carcasses.

The objective of this study was to determine Salmonella contamination levels, presence and serovar distribution in broiler carcasses before and after chilling, as well as to evaluate the effectiveness of chilling process. A total of 96 pooled neck skin samples (PNSS) of 48 prechill (PreC) and 48 postchill (PosC) carcasses, representing 480 broilers collected in 6 mo' period were analyzed using ISO 6579-2:2012 Miniaturized Most Probable Number (ISO-mMPN) technique. Species confirmation and serovar identification was performed by Salmonella-specific real-time PCR (Salm-PCR) and conventional serotyping, respectively. Mean Salmonella count was 1.84 log10 MPN/g in PreC, and 1.48 log10 MPN/g in PosC samples, indicating a statistically significant reduction of 0.36 log10 MPN/g (p < 0.05) in the counts by plant's air chill system. Salmonella positivity reduced from 97.9% (47/48) in PreC to 85.42% (41/48) in PosC samples, confirmed by Salm-PCR with identified serovars as S. Virchow (89.77 %) followed by S. Schwarzengrund (9.09%) and S. Bredeney (1.14%). Persistence of high load and prevalence of Salmonella with serovar Virchow dominance (other than the ones mandated in current guidelines) in the final product contributes significant and up to date data to relevant literature, and provides unbiased epidemiological reference to legal authorities for future relevant revisions.

A broad host phage, CP6, for combating multidrug-resistant Campylobacter prevalent in poultry meat.

Campylobacter is a major cause of bacterial foodborne diarrhea worldwide. Consumption of raw or undercooked chicken meat contaminated with Campylobacter is the most common causative agent of human infections. Given the high prevalence of contamination in poultry meat and the recent rise of multi-drug-resistant (MDR) Campylobacter strains, an effective intervention method of reducing bird colonization is needed. In this study, the Campylobacter-specific lytic phage CP6 was isolated from chicken feces. Phage CP6 exhibited a broad host range against different MDR Campylobacter isolates (97.4% of strains were infected). Some biological characteristics were observed, such as a good pH (3-9) stability and moderate temperature tolerance (<50 ℃). The complete genome sequence revealed a linear double-stranded DNA (178,350 bp, group II Campylobacter phage) with 27.51% GC content, including 209 predicted open reading frames, among which only 54 were annotated with known functions. Phylogenetic analysis of the phage major capsid protein demonstrated that phage CP6 was closely related to Campylobacter phage CPt10, CP21, CP20, IBB35, and CP220. CP6 phage exerted good antimicrobial effects on MDR Campylobacter in vitro culture and reduced CFUs of the host cells by up to 1-log compared with the control in artificially contaminated chicken breast meat. Our findings suggested the potential of CP6 phage as a promising antimicrobial agent for combating MDR Campylobacter in food processing.

Investigation of Salmonella, hepatitis E virus (HEV) and viral indicators of fecal contamination in four Italian pig slaughterhouses, 2021-2022.

In the pork production chain, the control at slaughterhouse aims to ensure safe food thanks to proper hygienic conditions during all steps of the slaughtering. Salmonella is one of the main foodborne pathogens in the EU causing a great number of human cases, and pigs also contribute to its spreading. Pig is the main reservoir of the zoonotic hepatitis E virus (HEV) that can be present in liver, bile, feces and even rarely in blood and muscle. The aim of this study was to assess the presence of both Salmonella and HEV in several points of the slaughtering chain, including pig trucks. Other viruses hosted in the gut flora of pigs and shed in feces were also assayed (porcine adenovirus PAdV, rotavirus, norovirus, and mammalian orthoreovirus MRV). Torque teno sus virus (TTSuV) present in both feces, liver and blood was also considered. Four Italian pig abattoirs were sampled in 12 critical points, 5 of which were the outer surface of carcasses before processing. HEV and rotavirus (RVA) were not detected. Norovirus was detected once. Salmonella was detected in two of the 4 abattoirs: in the two lairage pens, in the site of evisceration and on one carcass, indicating the presence of Salmonella if carcass is improper handled. The sampling sites positive for Salmonella were also positive for PAdV. MRV was detected in 10 swabs, from only two abattoirs, mainly in outer surface of carcasses. TTSuV was also detected in all abattoirs. Our study has revealed a diverse group of viruses, each serving as indicator of either fecal (NoV, RVA, PAdV, MRV) or blood contamination (TTSuV). TTSuV could be relevant as blood contamination indicators, crucial for viruses with a viremic stage, such as HEV. The simultaneous presence of PAdV with Salmonella is relevant, suggesting PAdV as a promising indicator for fecal contamination for both bacterial and viruses. In conclusion, even in the absence of HEV, the widespread presence of Salmonella at various points in the chain, underscores the need for vigilant monitoring and mitigation strategies which could be achieved by testing not only bacteria indicators as expected by current regulation, but also some viruses (PAdV, TTSuV, MRV) which could represent other sources of fecal contamination.

Development of a closed-tube, calcein-based loop-mediated isothermal amplification assay to detect Salmonella spp. in raw meat samples.

Foodborne pathogens compromise food safety and public health, and Salmonella spp. are among the major pathogenic bacteria that cause outbreaks worldwide. Proper surveillance through timely and cost-effective detection methods across the food animal production chain is crucial to prevent Salmonella outbreaks and agricultural losses. Traditional culture methods are labor- and resource-intensive, with lengthy turnaround times. Meanwhile, conventional molecular tools, such as PCR and qPCR, are expensive and require technical skills and equipment. Loop-mediated isothermal amplification (LAMP) is a simple, rapid, inexpensive, highly sensitive, and specific molecular assay that does not require expensive equipment. Hence, this study developed and optimized a closed-tube, calcein-based LAMP assay to detect Salmonella using the invA gene and performed evaluation and validation against conventional PCR. The LAMP assay showed high specificity and sensitivity. It showed 10-fold higher sensitivity than conventional PCR, at <1 ng/µL DNA concentrations. Meanwhile, for CFU/mL, LAMP assay showed 1000-fold higher sensitivity than conventional PCR at 4.8 × 103 cells/mL than 4.8 × 107 cells/mL, respectively. For parallel testing of 341 raw meat samples, after conventional culture enrichment (until Rappaport-Vassiliadis broth), the optimized LAMP assay showed 100% detection on all samples while conventional PCR showed 100%, 99.04%, and 96.64% for raw chicken, beef, and pork samples, respectively. Meanwhile, a shortened enrichment protocol involving 3-h incubation in buffered peptone water only, showed lower accuracy in tandem with the optimized LAMP assay ranging from 55 to 75% positivity rates among samples. These suggest that the optimized LAMP assay possesses higher sensitivity over conventional PCR for invA gene detection when coupled with conventional enrichment culture methods. Hence, this assay has potential as a powerful complementary or alternative Salmonella detection method to increase surveillance capacity and protect consumer food safety and public health worldwide.

Microbial profile of broiler carcasses processed at a university scale mobile poultry processing unit.

Chicken and chicken products have been associated with foodborne pathogens such as Salmonella, Campylobacter, and Escherichia coli (E. coli). Poultry comprises an important segment of the agricultural economy (75 million birds processed as of 2019) in West Virginia (WV). The risk of pathogens on processed chickens has risen with the increased popularity of mobile poultry processing units (MPPUs). This study evaluated the microbial safety of broilers processed in a MPPU in WV. This study assessed aerobic plate counts (APCs), E. coli counts and the presence/absence of Salmonella and Campylobacter on 96 broiler carcasses following each MPPU step of scalding, eviscerating, and chilling. Samples were either chilled in ice water only (W) or ice water with 5 ppm chlorine (CW). The highest number of bacteria recovered from carcasses were APCs (4.21 log10CFU/mL) and E. coli (3.77 log10CFU/mL; P = 0.02). A total reduction of 0.30 (P = 0.10) and 0.63 (P = 0.01) log10CFU/mL for APCs and E. coli, respectively, occurred from chilling carcasses in CW. Overall, results show that E. coli, Salmonella, and Campylobacter were significantly (P < 0.05) reduced from the initial scalding to the chilling step. However, Salmonella frequency doubled (15.63-34.38%) after the evisceration step, indicating that washing carcasses after evisceration may be a critical control point in preventing cross-contamination by Salmonella. Proper chilling is also an important microbial mitigation step in MPPU processing. Results indicate that Campylobacter was more resistant to chilling than Salmonella. Campylobacter was not completely inactivated until carcasses were chilled in CW, whereas W was sufficient to reduce Salmonella on carcasses. The results led to the conclusion that although 5 ppm chlorine (Cl2) achieved more bacterial reductions than water alone, the reductions were not always significant (P > 0.05). Further MPPU studies are needed to verify more effective chilling and processing strategies.

Pseudomonas weihenstephanensis through the iron metabolism pathway promotes in situ spoilage capacity of prepared beef steaks during cold storage.

In this study, we evaluated the histomorphology, reactive oxygen species (ROS), protein degradation, and iron metabolism characteristics and differential expression analysis of genes for siderophores synthesis and protease secretion in prepared beef steaks inoculated alone or co-inoculated with P. weihenstephanensis, B. thermotrichothrix and M. caseolyticus at 4 °C for 12 days. The results showed that the P. weihenstephanensis was the key bacteria that degraded protein in the process of prepared beef steaks spoilage, which led to protein oxidation by promoting ferritin degradation to release free iron and inducing ROS accumulation. The highest expression of FpvA and AprE was detected in the P. weihenstephanensis group by comparing qRT-PCR of the different inoculation groups. Both qRT-PCR and Western blot revealed that ferritin heavy polypeptide and ferritin light chain polypeptide gene and protein expressions were significantly higher in the P. weihenstephanensis inoculation group compared to the other inoculation groups. Results suggested that FpvA and AprE might play roles in meat spoilage and were potential positional, physiological and functional candidate genes for improving the quality traits of prepared beef steaks. This work may provide insights on controlling food quality and safety by intervening in spoilage pathways targeting iron carrier biosynthesis or protease secretion genes.

Free-standing carboxymethyl cellulose film incorporating nanoformulated pomegranate extract for meat packaging.

This study aimed to explore an innovative approach to enhancing the shelf-life and quality of meat products through the application of an active packaging system. The study involved the development of new free-standing carboxymethyl cellulose (CMC) nanocomposite films incorporated with nanoencapsulated flavonoids derived from pomegranate extract. The loaded flavonoids, known for their antioxidant and antimicrobial properties, were nanoencapsulated via a self-assembly approach in a mixture of chitosan and sodium alginate to improve their stability, solubility, and controlled release characteristics. Chemical structure, size, and morphology of the obtained nanoparticles (Pg-NPs) were studied with FTIR, zeta-sizer, and TEM. The Pg-NPs showed particle size of 232 nm, and zeta-potential of -20.7 mV. Various free-standing nanocomposite films were then developed via incorporation of Pg-NPs into CMC-casted films. FTIR, SEM, thermal and mechanical properties, and surface wettability were intensively studied for the nanocomposite films. Barrier properties against water vapor were investigated at 2022 g·m-2d-1. The nanocomposite films possessed superior properties for inhibiting bacterial growth and extending the shelf-life of beef and poultry meat for 12 days compared with the Pg-NPs-free CMC films. This study presented a promising approach for development of active packaging systems with improved antimicrobial and antioxidant properties, and economic and environmental impacts.

Interventions to reduce Salmonella and Campylobacter during chilling and post-chilling stages of poultry processing: a systematic review and meta-analysis.

Salmonella and Campylobacter are common bacterial hazards causing foodborne illnesses worldwide. A large proportion of Salmonella and Campylobacter illnesses are attributed to contaminated poultry products that are mishandled or under cooked. Processing interventions such as chilling and post-chill dip are critical to reducing microbial contamination of poultry. A comprehensive search of the literature published between 2000 and 2021 was conducted in the databases Web of Science, Academic Search Complete, and Academic OneFile. Studies were included if they were in English and investigated the effects of interventions against Salmonella and/or Campylobacter on whole carcasses and/or parts during the chilling or post-chill stages of poultry processing. Random-effects meta-analyses were performed using the "meta" package in the R programming language. Subgroup analyses were assessed according to outcome measure reported, microorganism tested, processing stage assessed, and chemical treatment used. The results included 41 eligible studies. Eighteen studies reported results of 28 separate interventions against Salmonella and 31 reported results of 50 separate interventions against Campylobacter. No significant difference (P> 0.05) was observed when comparing the combined mean difference of all interventions targeting Salmonella to the combined mean difference of all interventions targeting Campylobacter or when comparing chilling times within each pathogen subgroup. For analyses examining antimicrobial additives, peroxyacetic acid (PAA) had the largest reduction against Salmonella population regardless of chilling time (P< 0.05). PAA also had the largest reduction against Campylobacter population and prevalence during primary chilling (P< 0.01). Air chilling showed a lower reduction for Campylobacter than any immersion chilling intervention (P< 0.05). Chilling time and antimicrobial used during poultry processing had varying effects depending on the pathogen and outcome measure investigated (concentration or prevalence). High heterogeneity and low sample numbers in most analyses suggest that more high-quality research that is well-designed and has transparent reporting of methodology and results is needed to corroborate the results.

Growth and Survival of Escherichia albertii in Food and Environmental Water at Various Temperatures.

Escherichia albertii is an emerging foodborne pathogen that causes diarrhea. E. albertii has been isolated from various foods, including pork and chicken meat, and environmental waters, such as river water. Although many food poisoning cases have been reported, there have been insufficient analyses of bacterial population behaviors in food and environmental water. In this study, we inoculated 2-5 log CFU of E. albertii into 25 g of pork, chicken meat, Japanese rock oyster, Pacific oyster, and 300 mL of well water and seawater at 4°C, 10°C, 20°C, and 30°C, and analyzed the bacterial population behavior in food and environmental water. After 3 days at 4°C, the population of E. albertii strain EA21 and EA24 in foods maintained approximately 4 log CFU/25 g. After 3 days at 10°C, the population of E. albertii strains in pork and oysters maintained approximately 4 log CFU/25 g, and that in chicken meat increased to approximately 5-6 log CFU/25 g. After 2 days at 20°C, E. albertii strains grew to approximately 6-7 log CFU/25 g in pork and chicken meat, and E. albertii strain EA21 but not EA24 grew to 4.5 log CFU/25 g in Japanese rock oyster, E. albertii strain EA21 but not EA24 slightly grew to 3.1 log CFU/25 g in Pacific oyster. After 1 day at 30°C, E. albertii strains grew to approximately 7-8 log CFU/25 g in chicken meat and pork, grew to approximately 4-6 log CFU/25 g in Japanese rock oyster, and 6-7 log CFU/25 g in Pacific oyster. These results suggest that E. albertii survives without growth below 4°C and grew rapidly at 20°C and 30°C in foods, especially in meat. E. albertii strains did not grow in well water and seawater at 4°C, 10°C, 20°C, and 30°C. The population of E. albertii strains in well water and seawater decreased faster at 30°C than at 4°C, 10°C, and 20°C, suggesting that E. albertii has low viability at 30°C in environmental water.

Carnobacterium maltaromaticum as bioprotective culture against spoilage bacteria in ground meat and cooked ham.

This study assessed the bioprotective effect of Carnobacterium maltaromaticum (CM) against Pseudomonas fluorescens (PF) and Brochothrix thermosphacta (BT) in ground beef and sliced cooked ham stored in high- and low-oxygen-modified atmospheres (66/4/30% O2/N2/CO2 and 70/30% N2/CO2, respectively). Both meat products were inoculated with CM, PF, and BT individually or in combination and stored for 7 days (3 days at 4 °C + 4 days at 8 °C) for ground beef and 28 days (10 days at 4 °C + 18 days at 8 °C) for sliced cooked ham. Each food matrix was assigned to 6 treatments: NC (no bacterial inoculation, representing the indigenous bacteria of meat), CM, BT, PF, CM + BT, and CM + PF. Bacterial growth, pH, instrumental color, and headspace gas composition were assessed during storage. CM counts remained stable from inoculation and throughout the shelf-life. CM reduced the population of inoculated and indigenous spoilage bacteria, including BT, PF, and enterobacteria, and showed a negligible impact on the physicochemical quality parameters of the products. Furthermore, upon simulating the shelf-life of ground beef and cooked ham, a remarkable extension could be observed with CM. Therefore, CM could be exploited as a biopreservative in meat products to enhance quality and shelf-life.

Epidemiology of multidrug-resistant zoonotic E. coli from beef processing and retail points in Delta State, Nigeria: Public health implications.

Some sorbitol non-fermenting E. coli (SN-F E. coli) and all E. coli O157 are zoonotic. Contamination of beef with zoonotic E. coli at the processing or retail point is a significant public health problem. Despite the public health importance of these organisms, there is no published data on the prevalence and antimicrobial resistance (AMR) of zoonotic E. coli from Delta State, Nigeria. Consequently, this study determined the prevalence and AMR of SN-F E. coli and E. coli O157 isolates from meat contact surfaces at the processing and retail points in the study area. The isolation, biochemical and serological characterisations and AMR status of the isolates were performed following standard microbiological methods. Overall prevalence of SN-F E. coli and E. coli O157 were 13.8% (56/406) and 1.5% (6/406), respectively. Majority of the 56 SN-F E. coli (64.3%, 36/56) and all the six E. coli O157 (10.7%, 6/56) detected in this study were found at the meat processing points. Most of the SN-F E. coli were isolated at the slaughterhouse floor (31%), meat hooks (17.2%) and meat sellers' knives (17.2%). The SN-F E. coli exhibited greater AMR to ampicillin (67.9%), gentamycin (64.3%) and tetracycline (50%) than other antimicrobial agents tested. No isolate was resistant to aztreonam. All six E. coli O157 isolates were resistant to enrofloxacin. Overall, 23 AMR patterns, comprised 14 from meat processing points and nine from meat retailing points, were observed from the 56 antimicrobial-resistant SN-F E. coli isolates. All the six E. coli O157 and 73.2% (41/56) of the SN-F E. coli isolates were multidrug-resistant. An overall mean multiple antimicrobial resistance index of 0.6 was recorded. Multidrug-resistant zoonotic E. coli were detected at meat processing and retail points in Delta State, Nigeria. The findings warrant the adoption of One Health control approach, "farm to fork" principle of food safety and prudent use of antimicrobial agents in animal agriculture. These may help to limit beef contamination with multidrug-resistant zoonotic E. coli at the processing and retailing points, for public health safety.

Occurrence and Characteristics of Toxigenic Staphylococcus aureus in Retail Foods in Iran.

Staphylococcus aureus causes various toxigenic and invasive diseases in humans worldwide. This study examined the prevalence, virulence genes, and antibiotic resistance of S. aureus isolates collected from 894 retail food samples in Ardabil, Iran. Staphylococcal cassette chromosome mec (SCCmec), spa, and multilocus sequence typing methods were employed to further investigate the molecular characteristics of methicillin-resistant S. aureus (MRSA) isolates. The results revealed that 11.18% (n = 100) of food samples exhibited contamination with S. aureus (10.50% methicillin-sensitive S. aureus [MSSA] and 0.67% MRSA). Notably, raw minced meat (29.41%), Faloodeh (25%), and Olivier salad (21.42%) emerged as the most frequently contaminated food items. Among the 100 isolates of S. aureus, 94% were characterized as MSSA, with the remaining 6% identified as MRSA. The highest resistance was observed for penicillin (12%). MRSA isolates exhibited significantly higher resistance rates. Seventy-nine percent of the isolates were positive for sea, 14% for seb, 8% for a sec, and 0% for sed enterotoxin-encoding genes. Sixteen percent of isolates harbored two or more staphylococcal enterotoxin genes, simultaneously. Moreover, 97%, 94%, 24%, and 22% of isolates were positive for hla, hld, tst, and pvl virulence-encoding genes, respectively. No isolate was positive for the exfoliative toxins encoding eta and etb genes. MRSA isolates belonged to CC8 (n = 4) and CC22 (n = 2). Isolates in CC8 belonged to lineage ST239-MRSA-III and spa type t030; the isolates in CC22 belonged to ST22-MRSA-IV and spa types t310 and t223. In conclusion, a relatively high proportion of our retail food samples were contaminated with S. aureus. The high incidence of isolates with toxigenic genes raises serious health concerns. Furthermore, the presence of MRSA lineages linked to humans suggests that retail foods may be contaminated with human origin.

Chitosan/oxidized Konjac Glucomannan films incorporated with Zanthoxylum Bungeanum essential oil: A novel approach for extending the shelf life of meat.

In this study, a novel edible composite film was prepared by chitosan, konjac glucomannan oxidized with ozone for 60 min (OKGM), and Zanthoxylum Bungeanum essential oil (ZEO). The chitosan/OKGM film was fortified with ZEO to assess the physical properties, structure, antioxidant and antibacterial abilities, and pork preservation systematically. Compared to the control group, the addition of 1 % ZEO increased tensile strength by 18.92 % and decreased water solubility, water vapor permeability, and moisture content by 10.05 %, 6.60 %, and 1.03 %, respectively. However, the treatment with ZEO (1.5 % and 2 %) decreased mechanical properties and increased the water vapor permeability. The ultraviolet barrier, antioxidant, and antibacterial abilities of composite films were enhanced by increasing the ZEO addition. Moreover, the COZ-1 film was used to protect the freshness of pork with slow-release behavior of ZEO. The results showed that addition of ZEO significantly decreased the pH value, total viable count, redness, total volatile basic nitrogen, and thiobarbituric acid and increased the hardness of pork after preservation for 10 days. Therefore, the chitosan/OKGM loaded with ZEO film can potentially be used as food packaging, providing new ideas for the research on active packaging materials.