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1.
Shokuhin Eiseigaku Zasshi ; 62(4): 129-132, 2021.
Artigo em Japonês | MEDLINE | ID: mdl-34470942

RESUMO

The sensitivity of the 3M TM Molecular Detection Assay 2-STEC Gene Screen (stx) assay (3M MDA2 STEC assay) was evaluated for verotoxin (VT) gene screening from food materials. The pure culture and foods such as sliced beef, tandoori paste, cucumber, etc. were used for this study. The sensitivity was obtained as 3 to 4 log CFU/mL in enrichment broth (BPW and mEC), which was cultured with food matrices. These results showed this detection kit was suitable the notification of standard methods from Ministry of health, which requires 4 log CFU/mL as detection limit in enrichment broth. This assay was useful as a rapid and simple screening method for VT gene from foods.


Assuntos
Contaminação de Alimentos , Microbiologia de Alimentos , Toxina Shiga , Escherichia coli Shiga Toxigênica , Animais , Bovinos , Escherichia , Escherichia coli Shiga Toxigênica/genética
2.
Molecules ; 26(15)2021 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-34361842

RESUMO

A new preservation approach is presented in this article to prolong the lifetime of raw chicken meat and enhance its quality at 4 °C via coating with highly soluble kidney bean protein hydrolysate. The hydrolysates of the black, red, and white kidney protein (BKH, RKH, and WKH) were obtained after 30 min enzymatic hydrolysis with Alcalase (E/S ratio of 1:100, hydrolysis degree 25-29%). The different phaseolin subunits (8S) appeared in SDS-PAGE in 35-45 kD molecular weight range while vicilin appeared in the molecular weight range of 55-75 kD. The kidney bean protein hydrolysates have considerable antioxidant activity as evidenced by the DPPH-scavenging activity and ß-carotine-linolenic assay, as well as antimicrobial activity evaluated by disc diffusion assay. BKH followed by RKH (800 µg/mL) significantly (p ≤ 0.05) scavenged 95, 91% of DPPH and inhibited 82-88% of linoleic oxidation. The three studied hydrolysates significantly inhibited the growth of bacteria, yeast, and fungi, where BKH was the most performing. Kidney bean protein hydrolysates could shield the chicken meat because of their amphoteric nature and many functional properties (water and oil-absorbing capacity and foaming stability). The quality of chicken meat was assessed by tracing the fluctuations in the chemical parameters (pH, met-myoglobin, lipid oxidation, and TVBN), bacterial load (total bacterial count, and psychrophilic count), color parameters and sensorial traits during cold preservation (4 °C). The hydrolysates (800 µg/g) significantly p ≤ 0.05 reduced the increment in meat pH and TVBN values, inhibited 59-70% of lipid oxidation as compared to control during 30 days of cold storage via eliminating 50% of bacterial load and maintained secured storage for 30 days. RKH and WKH significantly (p ≤ 0.05) enhanced L*, a* values, thus augmented the meat whiteness and redness, while, BKH increased b* values, declining all color parameters during meat storage. RKH and WKH (800 µg/g) (p ≤ 0.05) maintained 50-71% and 69-75% of meat color and odor, respectively, increased the meat juiciness after 30 days of cold storage. BKH, RKH and WKH can be safely incorporated into novel foods.


Assuntos
Galinhas/microbiologia , Conservantes de Alimentos , Carne/microbiologia , Phaseolus/química , Hidrolisados de Proteína , Subtilisinas/química , Animais , Microbiologia de Alimentos , Conservantes de Alimentos/química , Conservantes de Alimentos/farmacologia , Hidrolisados de Proteína/química , Hidrolisados de Proteína/farmacologia
3.
Arch Virol ; 166(10): 2763-2778, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34342747

RESUMO

White spot syndrome virus (WSSV) is a significant threat to the aquaculture sector, causing mortality among crabs and shrimps. Currently available diagnostic tests for WSSV are not rapid or cost-effective, and a new detection method is therefore needed. This study demonstrates the development of a biosensor by functionalization of magnetosomes with VP28-specific antibodies to detect WSSV in seafood. The magnetosomes (1 and 2 mg/ml) were conjugated with VP28 antibody (0.025-10 ng/µl), as confirmed by spectroscopy. The magnetosome-antibody conjugate was used to detect the VP28 antigen. The binding of antigen to the magnetosome-antibody complex resulted in a change in absorbance. The magnetosome-antibody-antigen complex was then concentrated and brought near a screen-printed carbon electrode by applying an external magnetic field, and the antigen concentration was determined using impedance measurements. The VP28 antigen (0.025 ng/µl) bound more efficiently to the magnetosome-VP28 antibody complex (0.025 ng/µl) than to the VP28 antibody (0.1 ng/µl) alone. The same assay was repeated to detect the VP28 antigen (0.01 ng/µl) in WSSV-infected seafood samples using the magnetosome-VP28 antibody complex (0.025 ng/µl). The WSSV in the seafood sample was also drawn toward the electrode due to the action of magnetosomes controlled by the external magnetic field and detected using impedance measurement. The presence of WSSV in seafood samples was verified by Western blot and RT-PCR. Cross-reactivity assays with other viruses confirmed the specificity of the magnetosome-based biosensor. The results indicate that the use of the magnetosome-based biosensor is a sensitive, specific, and rapid way to detect WSSV in seafood samples.


Assuntos
Técnicas Biossensoriais/veterinária , Magnetossomos , Alimentos Marinhos/virologia , Vírus da Síndrome da Mancha Branca 1/isolamento & purificação , Animais , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Aquicultura , Reações Cruzadas , Espectroscopia Dielétrica , Ensaio de Imunoadsorção Enzimática , Microbiologia de Alimentos , Magnetossomos/química , Magnetossomos/imunologia , Penaeidae/virologia , Reprodutibilidade dos Testes , Proteínas do Envelope Viral/análise , Proteínas do Envelope Viral/imunologia , Vírus da Síndrome da Mancha Branca 1/imunologia
4.
J Agric Food Chem ; 69(35): 10281-10291, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34432462

RESUMO

Food wastage represented by the deterioration of perishable food like fruits and vegetables is a serious global problem with tremendous ethical, financial, and environmental costs. The atmosphere (CO2 and O2) has a crucial role in food storage and can regulate physiological food metabolism and microbial growth. Modified atmosphere packaging (MAP) is a promising method used to extend shelf life and preserve the quality of perishable food; yet, its use depends on the specific gas permeability and selectivity of polymer membranes to generate an atmosphere desirable for storage. In this study, we established and validated a new plant leaf-mimetic shellac-based MAP membrane embedded with chitosan porous microspheres loaded with antimicrobial tannic acid (TA-CPM) as gas "switches" for regulating O2 and CO2 permeability and CO2/O2 selectivity. The effects of different amounts of TA-CPM added into the hybrid membranes were examined for litchi preservation at room temperature. Our results showed that this hybrid TA-CPM/shellac packaging membrane could regulate the internal CO2 and O2 concentrations and the CO2/O2 ratio within the packages containing litchis by adjusting the addition amount of TA-CPM. The 0.05% TA-CPM/shellac and 0.10% TA-CPM/shellac packages, especially 0.05% TA-CPM/shellac, generated a more desirable CO2 and O2 atmosphere for litchi preservation compared with controls, which was reflected by the delaying of browning and rotting, maintaining of the natural color of the litchi pericarp, preservation of pulp quality, inhibition of polyphenol oxidase and guaiacol peroxidase activities, and reduction of oxidative cell damage in litchis. The results suggested that 0.05% TA-CPM/shellac and 0.10% TA-CPM/shellac packaging membranes, especially 0.05% TA-CPM/shellac, could generate an ideal atmosphere for litchi storage at room temperature, demonstrating that this permeation-controlled hybrid membrane has great potential in food preservation and other applications requiring a modified atmosphere.


Assuntos
Litchi , Atmosfera , Microbiologia de Alimentos , Embalagem de Alimentos , Conservação de Alimentos , Frutas , Microesferas , Oxigênio , Porosidade
5.
Artigo em Inglês | MEDLINE | ID: mdl-34435946

RESUMO

Species belonging to the genus Sphingomonas have been isolated from environments such as soil, water and plant tissues. Many strains are known for their capability of degrading aromatic molecules and producing extracellular polymers. A Gram-stain-negative, strictly aerobic, motile, red-pigmented, oxidase-negative, catalase-positive, rod-shaped strain, designated DH-S5T, has been isolated from pork steak packed under CO2-enriched modified atmosphere. Cell diameters were 1.5×0.9 µm. Growth optima were at 30 °C and at pH 6.0. Phylogenetic analyses based on both complete 16S rRNA gene sequence and whole-genome sequence data revealed that strain DH-S5T belongs to the genus Sphingomonas, being closely related to Sphingomonas alpina DSM 22537T (97.4 % gene sequence similarity), followed by Sphingomonas qilianensis X1T (97.4 %) and Sphingomonas hylomeconis GZJT-2T (97.3 %). The DNA G+C content was 64.4 mol%. The digital DNA-DNA hybridization value between the isolate strain and S. alpina DSM 22537T was 21.0 % with an average nucleotide identity value of 77.03 %. Strain DH-S5T contained Q-10 as the ubiquinone and major fatty acids were C18 : 1 cis 11 (39.3 %) and C16 : 1 cis 9 (12.5 %), as well as C16 : 0 (12.1 %) and C14 : 0 2-OH (11.4 %). As for polar lipids, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, dimethylphosphatidylethanolamine and sphingoglycolipid could be detected, alongside traces of monomethylphosphatidylethanolamine. Based on its phenotypic, chemotaxonomic and phylogenetic characteristics, strain DH-S5T (=DSM 110829T=LMG 31606T) is classified as a representative of the genus Sphingomonas, for which the name Sphingomonas aliaeris sp. nov. is proposed.


Assuntos
Filogenia , Carne de Porco , Sphingomonas , Animais , Atmosfera , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Microbiologia de Alimentos , Alemanha , Fosfolipídeos/química , Pigmentação , Carne de Porco/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Sphingomonas/classificação , Sphingomonas/isolamento & purificação , Suínos
6.
J Food Prot ; 84(9): 1555-1559, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34380146

RESUMO

ABSTRACT: In this study, Bacillus cereus was isolated from soft soybean curds, and a dynamic model was developed to describe the kinetic behavior of these isolates during transfer and storage. B. cereus isolates recovered from soft soybean curds were inoculated into soft soybean curd, and the levels were determined during storage at 10 to 30°C. The B. cereus counts were fitted to the Baranyi model to calculate maximum growth rate (µmax) and lag-phase duration (LPD). These kinetic parameters were then analyzed with a polynomial equation to evaluate the effects of temperature on the kinetic parameters. The developed model was validated with observed values, and the differences between predicted and observed values were determined by calculating the root mean square error (RMSE). A dynamic model was then developed with a combination of primary and secondary models to describe B. cereus growth under changing temperature conditions. B. cereus was detected in two soft soybean curd samples (5.1%) at 0.7 log CFU/g. The µmax was -0.04 to 0.47 log CFU/g/h, and the ln(LPD) was 3.94 to 0.04 h, depending on the storage temperature. The model performance was appropriate with a 0.216 RMSE and accurately described the kinetic behavior of B. cereus in soft soybean curd samples. These results suggest that B. cereus can contaminate soft soybean curds and that the models developed with the B. cereus isolates are useful for describing the kinetic behavior of B. cereus in soft soybean curd.


Assuntos
Bacillus cereus , Soja , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Temperatura
7.
Int J Mol Sci ; 22(15)2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34360657

RESUMO

Although some metallic nanoparticles (NPs) are commonly used in the food processing plants as nanomaterials for food packaging, or as coatings on the food handling equipment, little is known about antimicrobial properties of palladium (PdNPs) and platinum (PtNPs) nanoparticles and their potential use in the food industry. In this study, common food-borne pathogens Salmonella enterica Infantis, Escherichia coli, Listeria monocytogenes and Staphylococcus aureus were tested. Both NPs reduced viable cells with the log10 CFU reduction of 0.3-2.4 (PdNPs) and 0.8-2.0 (PtNPs), average inhibitory rates of 55.2-99% for PdNPs and of 83.8-99% for PtNPs. However, both NPs seemed to be less effective for biofilm formation and its reduction. The most effective concentrations were evaluated to be 22.25-44.5 mg/L for PdNPs and 50.5-101 mg/L for PtNPs. Furthermore, the interactions of tested NPs with bacterial cell were visualized by transmission electron microscopy (TEM). TEM visualization confirmed that NPs entered bacteria and caused direct damage of the cell walls, which resulted in bacterial disruption. The in vitro cytotoxicity of individual NPs was determined in primary human renal tubular epithelial cells (HRTECs), human keratinocytes (HaCat), human dermal fibroblasts (HDFs), human epithelial kidney cells (HEK 293), and primary human coronary artery endothelial cells (HCAECs). Due to their antimicrobial properties on bacterial cells and no acute cytotoxicity, both types of NPs could potentially fight food-borne pathogens.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Doenças Transmitidas por Alimentos/prevenção & controle , Nanopartículas Metálicas/administração & dosagem , Paládio/química , Platina/química , Antibacterianos/química , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Células Cultivadas , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Microbiologia de Alimentos , Humanos , Rim/citologia , Rim/efeitos dos fármacos , Nanopartículas Metálicas/química
8.
Food Res Int ; 147: 110464, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399463

RESUMO

Fresh food products, including fruits, vegetables, raw meat, and poultry, have been associated with safety concerns and quality issues, owing to their susceptibility to rapid deterioration and microbial contamination. This research aimed to develop an integrated process to simultaneously cool and decontaminate high moisture food products. Cold plasma (CP), a novel decontamination technology, was integrated with vacuum cooling to develop a plasma integrated low-pressure cooling (PiLPC) process. To evaluate the rapid cooling and microbial inactivation efficacies of the PiLPC process, fresh cut Granny Smith apples andSalmonella entericaserovarTyphimurium ATCC 13311 were used as the model food and microorganism, respectively. The influence of process parameters including treatment time, pressure, and post-treatment storage, on the inactivation ofSalmonellaon fresh-cut apples was investigated.Inactivation ofSalmonellaincreased with treatment time, with a maximum reduction of 3.21 log CFU/g after 5 min of CP treatment at atmospheric pressure. Inactivationof Salmonellaafter CP treatment at 200 mbar was not significantly different from that at atmospheric pressure for the same treatment time. CP treatment of 3 min at 200 mbar followed by a post-treatment storage of 3 days at 4 °C reduced the totalSalmonellapopulation on cut apple slices by > 6 log CFU/g. The temperature of the cut apples was reduced from room temperature to 2 °Cin 3 to 9 min depending on the sample surface area to volume ratio, when the pressure was reducedto 7 mbar. However, this PiLPC process resulted in moisture loss in cut apples. The results of this study indicate the potential of the PiLPC process for rapid cooling and microbial inactivation of fresh food products in a single process.


Assuntos
Malus , Contagem de Colônia Microbiana , Manipulação de Alimentos , Microbiologia de Alimentos , Salmonella
9.
Food Res Int ; 147: 110480, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399476

RESUMO

This study describes the characterization and genomic analysis of six lytic Salmonella phages. To examine the feasibility of using these phages as biocontrol agents, we analyzed their genomes and compared them to those of similar phages. These six phages belong to genus Epseptimavirus, family Demerecviridae. We identified the genes of these six phages by comparing their genomes with those of three type phages in subfamily Markadamsvirinae. All six phages examined in this study were obligately lytic and did not carry undesirable genes. Two phages (vB_SalS_1-23 and vB_SalS_3-29) were selected as the representative phages for general characterization and physiological tests. The biocontrol efficacy of the representative phages was determined by comparing the viable counts of recovered host Salmonella ser. Newlands ZC-S1 from treatment and phage-free control samples. The biocontrol experiment showed that the representative phages were able to reduce the counts of ZC-S1 to below 2 log10 CFU/mL (~4.3 log10 CFU/mL reduction) at 3 h post-infection at 37 °C. Furthermore, we investigated the application of these two phages in the control of ZC-S1 contamination in chicken products and on eggshells. When applied to the surfaces of the samples, the phage cocktail (MOI = 100) reduced the ZC-S1 count to below 2 log10 CFU/mL on chicken skin and to undetectable levels (1 log10 CFU/mL) in chicken breast meat, ground chicken meat and eggshell samples (p < 0.01). Compared to the initial experiment, the phage cocktail reduced the ZC-S1 count by 2-4.08 log10 CFU/mL when applied at an MOI = 1 (except in the ground chicken meat group) and by 4.48-5.67 log10 CFU/mL at an MOI = 100 after 7 h. In conclusion, these two phages with lytic effects show a high potential to inhibit the growth of Salmonella contaminants and can be used as candidate biocontrol agents.


Assuntos
Bacteriófagos , Fagos de Salmonella , Bacteriófagos/genética , Microbiologia de Alimentos , Carne , Salmonella , Fagos de Salmonella/genética
10.
Food Res Int ; 147: 110484, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399480

RESUMO

Aeromonas hydrophila is an emerging foodborne pathogen capable of causing human gastroenteritis, and the main reservoir is the aquatic environment. In this study, the prevalence and virulence of A. hydrophila in seafoods and ready-to-eat (RTE) sushi distributed in various conditions (refrigerated, dried, or frozen) or seasons was investigated. Strains were isolated from seafood (refrigerated or frozen oysters, sashimi, and processed fish; n = 333) and RTE sushi (n = 88) samples collected in South Korea and then genetically analyzed for gastroenteritis-related virulence genes (aer, ast, and alt). Raw oysters showed the highest prevalence of A. hydrophila (57.1%; 47/91) among all seafoods. Among the sashimi samples, flatfish sashimi (54.8%; 34/62) and salmon sushi (51.4%; 18/35) were the most prevalent. A. hydrophila was not detected in the oysters or anchovies distributed as either frozen or dried products. Seasonal investigations of sashimi and sushi showed that the summer prevalence of A. hydrophila with putative virulence genes was significantly lower in sashimi but highest in sushi. These results indicated that sushi could have been contaminated from several sources during the manufacturing or distribution processes. Significant correlations among the prevalence of putative virulence genes were confirmed, although no combination of genes presented a Phi correlation coefficient above 0.5 (0.26-0.43). To our knowledge, this is the first study to investigate the prevalence of A. hydrophila in various types of retail seafoods and RTE sushi in the East Asia region and then relate the prevalence to the distribution conditions of the samples. This study provides background information on the level of potential risk posed by A. hydrophila in retail seafoods and RTE sushi.


Assuntos
Aeromonas hydrophila , Microbiologia de Alimentos , Aeromonas hydrophila/genética , Animais , Humanos , Alimentos Marinhos , Estações do Ano , Virulência
11.
Food Res Int ; 147: 110491, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399487

RESUMO

The present study aimed to investigate the effect of chitosan edible coating containing 0.15% oregano essential oil (OEO) or 0.60% cinnamon essential oil (CEO) on the quality characteristics and dynamic changes in the bacterial community of roast duck slices under modified atmosphere packaging (MAP, 30% CO2/70% N2) during 21 days of storage at 2 ± 2 °C. The results showed that the application of chitosan coating (CH) alone inhibited the growth of microorganisms and prevented lipid oxidation throughout storage. Moreover, the storage stability was further improved by including OEO or CEO, which lowered (P < 0.05) values for total viable count (TVC), Enterobacteriaceae, 2-thiobarbituric acid reactive substance (TBARS) and total volatile basic nitrogen (TVB-N). Based on the microbiological results, the shelf-life of CH-OEO and CH-CEO treated roast duck slices was prolonged by at least 7 days compared to that of the control. In addition, packaging types applied in this study played a major role in the bacterial community development. Notably, Vibrio spp. were the most predominant bacteria in all samples, when TVC values approached the shelf-life threshold, suggesting that this bacterium may be the main contributor to the spoilage of roast duck. The growth inhibition of Vibrio spp. in the CH-OEO and CH-CEO treatments during the early period of chilled storage might be the reason for the extension of the shelf life. Taken together, CH incorporated with OEO or CEO could be developed as prospective edible packaging materials to preserve roast duck meat.


Assuntos
Quitosana , Óleos Voláteis , Origanum , Animais , Atmosfera , Bactérias , Quitosana/farmacologia , Cinnamomum zeylanicum , Patos , Microbiologia de Alimentos , Embalagem de Alimentos , Conservação de Alimentos , Carne , Óleos Voláteis/farmacologia , Estudos Prospectivos
12.
Food Res Int ; 147: 110548, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399525

RESUMO

Salmonella contamination of low-water activity (aw) foods poses a serious concern worldwide. The present study was conducted to assess the effects of drying conditions, food composition, and water activity on the desiccation tolerance and thermal resistance of S. Enteritidis FUA1946, S. Senftenberg ATCC43845 and S. Typhimurium ATCC13311 in pet food, binder formulation, and skim milk powder. The samples were wet inoculated with the individual Salmonella strains and were equilibrated to aw 0.33 and 0.75, followed by an isothermal treatment at 70 °C. The thermal inactivation data was fitted to the Weibull model. Irrespective of the aw, food composition and physical structure of the selected foods, strain S. Enteritidis FUA1946 displayed the highest desiccation and thermal resistance, followed by S. Senftenberg ATCC43845 and S. Typhimurium ATCC13311. The food matrix and strain type significantly (p < 0.05) influenced the thermal resistance of microorganisms in foods along with aw change during thermal treatments. To further study the effect of food composition, an additional set of experiments using dry inoculation of the resistant Salmonella strain in the low-aw foods was designed. Significant (p < 0.05) matrix-dependent interaction on Salmonella reduction was observed. The water adsorption isotherms of selected low-aw foods were measured at 20 and 70 °C to relate the thermal inactivation kinetics with the change in the aw. The characterization of thermal resistance of the Salmonella serovars in low-aw products with different compositions and aw in this study may be used for the validation of thermal challenge studies.


Assuntos
Salmonella enterica , Microbiologia de Alimentos , Temperatura Alta , Salmonella , Água/análise
13.
Viruses ; 13(7)2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34372557

RESUMO

Human coronaviruses, including SARS-CoV-2, are known to spread mainly via close contact and respiratory droplets. However, other potential means of transmission may be present. Fomite-mediated transmission occurs when viruses are deposited onto a surface and then transfer to a subsequent individual. Surfaces can become contaminated directly from respiratory droplets or from a contaminated hand. Due to mask mandates in many countries around the world, the former is less likely. Hands can become contaminated if respiratory droplets are deposited on them (i.e., coughing or sneezing) or through contact with fecal material where human coronaviruses (HCoVs) can be shed. The focus of this paper is on whether human coronaviruses can transfer efficiently from contaminated hands to food or food contact surfaces. The surfaces chosen were: stainless steel, plastic, cucumber and apple. Transfer was first tested with cellular maintenance media and three viruses: two human coronaviruses, 229E and OC43, and murine norovirus-1, as a surrogate for human norovirus. There was no transfer for either of the human coronaviruses to any of the surfaces. Murine norovirus-1 did transfer to stainless steel, cucumber and apple, with transfer efficiencies of 9.19%, 5.95% and 0.329%, respectively. Human coronavirus OC43 transfer was then tested in the presence of fecal material, and transfer was observed for stainless steel (0.52%), cucumber (19.82%) and apple (15.51%) but not plastic. This study indicates that human coronaviruses do not transfer effectively from contaminated hands to contact surfaces without the presence of fecal material.


Assuntos
COVID-19/transmissão , Infecções por Coronavirus/transmissão , Microbiologia de Alimentos , SARS-CoV-2/fisiologia , COVID-19/virologia , Linhagem Celular , Resfriado Comum/transmissão , Coronavirus/isolamento & purificação , Coronavirus Humano 229E/isolamento & purificação , Coronavirus Humano OC43/isolamento & purificação , Contaminação de Equipamentos , Fezes/virologia , Fômites , Doenças Transmitidas por Alimentos/virologia , Humanos , Norovirus/isolamento & purificação , Aço Inoxidável
14.
Zhonghua Yu Fang Yi Xue Za Zhi ; 55(8): 999-1005, 2021 Aug 06.
Artigo em Chinês | MEDLINE | ID: mdl-34445840

RESUMO

To optimize the quantitative detection method for Salmonella enterica and analyze the quantitative contamination level of Salmonella enterica in raw pork samples from farmer's markets in Chengdu. Based on qualitative detection standard method of Salmonella enterica in China (GB 4789.4-2016) and the quantitative detection method of FSIS in the United States (MLG 4.08 and MLG appendix 2.05 MPN), the selective enrichment broth, screening plate, identification method and quantitative dilution ratio in quantitative detection of Salmonella enterica were optimized using 70 samples of raw pork. The optimized method compared by student's t-test was used to detect 40 samples of raw pork collected from farmer's markets in Chengdu from June to October 2020. For isolation of Salmonella from raw pork samples, the coincidence degree of TTB enrichment solution was significantly higher than that of RV enrichment solution (0.93±0.32 vs 0.35±0.62,t=8.324,P=0.001) and the consistency of suspicious colonies screened by XLT4 plate was significantly higher than that of Salmonella chromogenic medium (0.77±0.09 vs 1.00±0.00,t=2.971,P =0.017). The MPN method used 4 successive gradient dilutions, namely 12 tube method, could obtain more accurate quantitative value for Salmonella enterica. The combined use of selective enrichment broth TTB, XLT4 plate, Real-time PCR and MALDI-TOF mass spectrometry could get better results for screening and identifying Salmonella enterica. The detection rate for Salmonella enterica isolated from raw pork in farmer's markets was 92.5% (37/40). The most of the Salmonella positive samples (83.8%, 31/37) were detected with a contamination level ranged from 0.1 to 55 MPN/g. The optimized quantitative detection method for Salmonella enterica in raw pork in this study can effectively screen the target bacteria and obtain more accurate quantitative value.


Assuntos
Carne de Porco , Carne Vermelha , Salmonella enterica , Animais , Fazendeiros , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Humanos , Suínos
15.
Molecules ; 26(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34361741

RESUMO

Due to their richness of bioactive substances, rose hips are a valuable raw material for obtaining extracts with potential antimicrobial activity. The aim of the study was to determine the antagonistic potential of whole pseudo-fruit and flesh extracts of three Rosa sp. varieties against Staphylococcus spp. bacteria isolated as food contaminants. The biological material in this study consisted of seven strains of bacteria from the genus Staphylococcus. Two strains-Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis DSMZ 3270-were used as reference strains. The other five strains were food-derived isolates-S. epidermidis A5, S. xylosus M5, S. haemolyticus M6, S. capitis KR6, and S. warneri KR2A. The material was the pseudo-fruits of Rosa canina, Rosa pomifera Karpatia, and Rosa rugosa. The polyphenols were extracted from the fleshy part and the whole pseudo-fruit for all rose varieties. The tested preparations differed significantly in their polyphenol composition. The sum of polyphenols ranged from 28 862 to 35 358 mg/100 g of lyophilisate. The main groups of polyphenols found in the preparations were flavanols and ellagitannins. All of the tested extracts inhibited the growth of staphylococci at a concentration of 500 mg/mL. Rosa rugosa fruit extract showed the strongest antimicrobial properties among the studied extracts. For all the strains, the growth inhibition had a diameter of 20.3-29.0 mm. Moreover, six out of the seven tested strains showed the highest inhibition with the use of this extract. The MIC of rose extracts was in the range of 3.125-500 mg/mL and was strictly dependent on the bacterial species, the species of the rose, and the part of the fruit from which the extract was obtained. Correlations were assessed between the main groups of polyphenols in the extracts and their inhibition of bacterial growth. In the case of pseudo-fruit extracts, the inhibitory effect on bacterial growth positively correlated with the content of ellagitannins, and this effect was observed for almost all the tested strains. The results presented herein follow the current trend of minimising the use of chemical preservatives in food; from this point of view, rose extracts are very promising.


Assuntos
Antibacterianos/química , Flavonoides/química , Taninos Hidrolisáveis/química , Polifenóis/química , Rosa/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos/métodos , Frutas/química , Humanos , Taninos Hidrolisáveis/isolamento & purificação , Taninos Hidrolisáveis/farmacologia , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Polifenóis/isolamento & purificação , Polifenóis/farmacologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus capitis/efeitos dos fármacos , Staphylococcus capitis/crescimento & desenvolvimento , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/crescimento & desenvolvimento , Staphylococcus haemolyticus/efeitos dos fármacos , Staphylococcus haemolyticus/crescimento & desenvolvimento
16.
Wei Sheng Yan Jiu ; 50(4): 646-664, 2021 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-34311838

RESUMO

OBJECTIVE: A quantitative microbiological risk assessment was conducted for Salmonella spp. in fresh pork from retail stores to consumers in China in order to provide evidence for adopting effective risk management measures. METHODS: The national food safety and risk monitoring data was used to estimate the initial contamination level of Salmonella in the retail fresh pork. The growth model and the cross-contamination model of Salmonella were referenced from the ComBase data base and scientific literature, respectively. Then the human health risk was predicted by the consumption of Salmonella-contaminated fresh pork and the Beta-Poisson dose-response model. RESULTS: The number of Salmonellosis per year among 1 million residents due to fresh pork was estimated to be 4748.The sensitivity analysis showed that the risk of Salmonellosis was mainly and positively correlated with the preparation rate of ready to eat food, the consumption quantity of pork, the initial contamination level of Salmonella in fresh pork, and the proportion of improper cleaning of knives and chopping boards. When the contamination level of Salmonella in fresh pork is controlled below 1 CFU/g, the average probability of illness will be reduced by 59.39%; the average probability of illness will be reduced by 58.97% by increasing the ratio of complete cleaning of chopping boards or the separation ratio of chopping boards for raw and ready-to-eat food to 90%. CONCLUSION: The risk could be effectively reduced by controlling the concentration of Salmonella contamination in retail pork or improving hygiene practices.


Assuntos
Carne de Porco , Carne Vermelha , Animais , China , Contaminação de Alimentos/análise , Manipulação de Alimentos , Microbiologia de Alimentos , Humanos , Medição de Risco , Salmonella , Suínos
17.
Artigo em Inglês | MEDLINE | ID: mdl-34313582

RESUMO

Thirteen Gram-stain-positive bacterial strains were isolated from Chinese traditional pickle and the gut of honeybee (Apis mellifera). These strains were characterized using a polyphasic taxonomic approach. The data demonstrated that 12 of the 13 strains represented eight novel species belonging to the genera Apilactobacillus, Secundilactobacillus, Levilactobacillus and Lacticaseibacillus; strains HN36-1T, 887-11T, F79-211-2T, 866-3T, 6-5(1)T, 13B17T, 117-1T and ZW152T were designated as the type strains. Based upon the data of polyphasic characterization obtained in the present study, eight novel species, Apilactobacillus nanyangensis sp. nov., Secundilactobacillus hailunensis sp. nov., Secundilactobacillus yichangensis sp. nov., Levilactobacillus andaensis sp. nov., Levilactobacillus wangkuiensis sp. nov., Levilactobacillus lanxiensis sp. nov., Lacticaseibacillus mingshuiensis sp. nov. and Lacticaseibacillus suilingensis sp. nov., are proposed and the type strains are HN36-1T (=JCM 33867T=CCTCC AB 2019385T), 887-11T (=NCIMB 15201T=CCM 8950T=JCM 33864T=CCTCC AB 2018396T), F79-211-2T (=NCIMB 15254T=JCM 33866T=CCTCC AB 2019384T), 866-3T (=JCM 33863T=CCTCC AB 2019383T), 6-5(1)T (=NCIMB 15229T=CCM 8977T=JCM 33564T=CCTCC AB 2019168T), 13B17T (=NCIMB 15230T=CCM 8979T=JCM 33565T=CCTCC AB 2019167T), 117-1T (=NCIMB 15232T=CCM 8980T=JCM 33567T) and ZW152T (=JCM 34363T=CCTCC AB 2020299T=LMG 32143T=CCM 9110T), respectively.


Assuntos
Abelhas/microbiologia , Alimentos e Bebidas Fermentados/microbiologia , Lactobacillaceae/classificação , Filogenia , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Microbiologia de Alimentos , Genes Bacterianos , Lactobacillaceae/isolamento & purificação , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
18.
Curr Microbiol ; 78(9): 3403-3416, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34241669

RESUMO

Cronobacter spp. can cause foodborne diseases in infants, but Cronobacter infections in healthy adults and vulnerable people have also been reported. These bacteria have ubiquitous nature and can contaminate various foods. Therefore, we assessed the presence of Cronobacter spp. in popularly consumed ready-to-eat (RTE) food products. In the present study, 51 (15%) of the 340 RTE food samples were contaminated with Cronobacter spp The highest contamination rates were found in spices (46.7%), meat-free cig koftes (44.4%), desserts (23.3%), cereals (23.1%), doners (12.2%), and ice cream (11.1%). Phenotypic and molecular methods, including 16S rRNA, gluA, rpoB, cgcA genes, and fusA allele sequencing were tested to identify Cronobacter species. Of the 51 contaminated samples, 54 isolates were identified as C. sakazakii (n = 43), C. malonaticus (n = 7), C. muytjensii (n = 3) and C. turicensis (n = 1) using fusA analysis. These isolates were assigned to 15 different fusA alleles, two of which (191 and 192) were new alleles. Putative virulence factors such as the ompA and zpx gene, biofilms, and siderophores were detected in most of the Cronobacter isolates (> 85%). Cronobacter isolates were resistant to cephalothin (85.2%), cefoxitin (33.3%), cefotaxime (14.8%), ampicillin (11.1%), cefepime (5.6%), aztreonam (5.6%), and piperacillin (1.9%). The multidrug resistance (against three or more classes of antimicrobial agents) was 7.4%. The results indicated presence of Cronobacter spp. in RTE foods, which may be a risk to human health. It is important to adopt rigorous hygiene and sanitization practices to ensure the microbiological safety of these foods consuming without any processing.


Assuntos
Cronobacter sakazakii , Cronobacter , Antibacterianos/farmacologia , Cronobacter/genética , Cronobacter sakazakii/genética , Microbiologia de Alimentos , Humanos , Lactente , Testes de Sensibilidade Microbiana , RNA Ribossômico 16S/genética , Virulência
19.
Epidemiol Infect ; 149: e190, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-34275497

RESUMO

About 800 foodborne disease outbreaks are reported in the United States annually. Few are associated with food recalls. We compared 226 outbreaks associated with food recalls with those not associated with recalls during 2006-2016. Recall-associated outbreaks had, on average, more illnesses per outbreak and higher proportions of hospitalisations and deaths than non-recall-associated outbreaks. The top confirmed aetiology for recall-associated outbreaks was Salmonella. Pasteurised and unpasteurised dairy products, beef and molluscs were the most frequently implicated foods. The most common pathogen-food pairs for outbreaks with recalls were Escherichia coli-beef and norovirus-molluscs; the top pairs for non-recall-associated outbreaks were scombrotoxin-fish and ciguatoxin-fish. For outbreaks with recalls, 48% of the recalls occurred after the outbreak, 27% during the outbreak, 3% before the outbreak, and 22% were inconclusive or had unknown recall timing. Fifty per cent of recall-associated outbreaks were multistate, compared with 2% of non-recall-associated outbreaks. The differences between recall-associated outbreaks and non-recall-associated outbreaks help define the types of outbreaks and food vehicles that are likely to have a recall. Improved outbreak vehicle identification and traceability of rarely recalled foods could lead to more recalls of these products, resulting in fewer illnesses and deaths.


Assuntos
Contaminação de Alimentos , Doenças Transmitidas por Alimentos/epidemiologia , Surtos de Doenças , Contaminação de Alimentos/legislação & jurisprudência , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Legislação sobre Alimentos , Estados Unidos
20.
Sensors (Basel) ; 21(13)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206251

RESUMO

Vacuum packaging (VP) is used to reduce exposure of retail meat samples to ambient oxygen (O2) and preserve their quality. A simple sensor system produced from commercial components is described, which allows for non-destructive monitoring of the O2 concentration in VP raw meat samples. Disposable O2 sensor inserts were produced by spotting small aliquots of the cocktail of the Pt-benzoporphyrin dye and polystyrene in ethyl acetate onto pieces of a PVDF membrane and allowing them to air-dry. These sensor dots were placed on top of the beef cuts and vacuum-packed. A handheld reader, FirestinGO2, was used to read nondestructively the sensor phase shift signals (dphi°) and relate them to the O2 levels in packs (kPa or %). The system was validated under industrial settings at a meat processing plant to monitor O2 in VP meat over nine weeks of shelf life storage. The dphi° readings from individual batch-calibrated sensors were converted into the O2 concentration by applying the following calibration equation: O2 (%) = 0.034 * dphi°2 - 3.413 * dphi° + 85.02. In the VP meat samples, the O2 levels were seen to range between 0.12% and 0.27%, with the sensor dphi signals ranging from 44.03° to 56.02°. The DIY sensor system demonstrated ease of use on-site, fast measurement time, high sample throughput, low cost and flexibility.


Assuntos
Embalagem de Alimentos , Carne , Animais , Bovinos , Microbiologia de Alimentos , Carne/análise , Oxigênio/análise , Vácuo
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