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1.
Int J Food Microbiol ; 346: 109159, 2021 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-33773356

RESUMO

The foodborne pathogen L. monocytogenes can be present in food processing environments where it is exposed to various stressors. These antimicrobial factors, which aim to eliminate the pathogen, can induce sub-lethal injury to the bacterial cells. In the present study, we investigated the efficacy of different treatments (stresses) relevant to food processing and preservation as well as sanitation methods, in generating sub-lethal injury at 4 °C and 20 °C to two L. monocytogenes strains, ScottA and EGDe. Additionally, we evaluated the survival and extent of L. monocytogenes injury after exposure to commonly used disinfectants (peracetic acid and benzalkonium chloride), following habituation in nutrient-deprived, high-salinity medium. Each stress had a different impact on the survival and injury kinetics of L. monocytogenes. The highest injury levels were caused by peracetic acid which, at 4 °C, generated high populations of injured cells without loss of viability. Other injury-inducing stresses were lactic acid and heating. Long-term habituation in nutrient-limited and high salinity medium (4 °C) and subsequent exposure to disinfectants resulted in higher survival and injury in benzalkonium chloride and increased survival, yet with lower injury levels, in peracetic acid at 20 °C. Taken together, these results highlight the potential food safety risk emerging from the occurrence of injured cells by commonly used food processing methods. Consequently, in order to accurately assess the impact of an antimicrobial method, its potential of inducing sublethal injury needs to be considered along with lethality.


Assuntos
Desinfetantes/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Compostos de Benzalcônio/farmacologia , Manipulação de Alimentos/instrumentação , Cinética , Listeria monocytogenes/química , Listeria monocytogenes/fisiologia , Viabilidade Microbiana/efeitos dos fármacos , Ácido Peracético/farmacologia , Estresse Fisiológico/efeitos dos fármacos
2.
Food Microbiol ; 97: 103758, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33653529

RESUMO

Listeria monocytogenes is a foodborne pathogen that causes a life-threatening disease in humans known as listeriosis. Contamination of food during processing is the main route of transmission of Listeria monocytogenes. Therefore, biocides play a crucial role in food processing environments as they act as the first line of defense in the prevention and control of L. monocytogenes. Residues of biocides may be present at sublethal concentrations after disinfection. This, unfortunately, subjects L. monocytogenes to selection pressure, giving rise to tolerant strains, which pose a threat to food safety and public health. This review will give a brief description of L. monocytogenes, the clinical manifestation, treatment of listeriosis as well as recently recorded outbreaks. The article will then discuss the current literature on the ability of L. monocytogenes strains to tolerate biocides especially quaternary ammonium compounds as well as the mechanisms of tolerance towards biocides including the activation of efflux pump systems.


Assuntos
Desinfetantes/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Animais , Desinfecção/instrumentação , Desinfecção/métodos , Farmacorresistência Bacteriana , Manipulação de Alimentos/instrumentação , Inocuidade dos Alimentos , Humanos , Listeria monocytogenes/genética , Listeria monocytogenes/crescimento & desenvolvimento , Listeriose/epidemiologia
3.
J Food Sci ; 86(3): 942-951, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33565641

RESUMO

The properties of flours and extrusion characteristics, of three lentil varieties (Brewer, Crimson, and Richlea) were studied. The effects of barrel temperature (110, 125, and 140 °C) and screw speed (150, 200, and 250 rpm) on process responses and extrudate characteristics were evaluated using a corotating twin-screw extruder. The three varieties of lentils had significant differences (p < 0.05) in their starch (48.7% to 50.9%), protein (20.4% to 22.7%), and fat content (1.3% to 1.9%), gelatinization temperature (71.7 to 74.6 °C), peak viscosity (123.3 to 179.7 mPa.s), and melting temperature (113.6 to 119.7 °C). The lentil variety, barrel temperature, and screw speed significantly impacted the process responses and extrudate properties. Whole lentil flours exhibited the highest expansion ratio (3.0 to 3.6) at the lowest temperature (110 °C) and the highest screw speed (250 rpm). Richlea variety had the highest expansion ratio (3.6) and the highest water solubility index (45.4%) as it had the highest starch content and peak viscosity, and the lowest protein content and melting temperature. Meanwhile, Brewer variety exhibited the lowest expansion ratio (1.9 to 3.0) compared to Richlea (2.5 to 3.6) and Crimson (2.4 to 3.0) in most of the extrusion conditions studied. Richlea variety was the most suitable for making direct-expanded extrudates among the varieties studied. The significant differences in the properties of flours from the three varieties of lentils resulted in significant impacts on the properties of their extrudates. Therefore, determining the properties of flours of different varieties is useful to select the appropriate varieties for extrusion processing. PRACTICAL APPLICATION: The information from this study is useful for the food industry to select the appropriate lentil varieties and processing conditions for the development of direct-expanded products. The data prove the importance of understanding the chemical composition, pasting, and thermal properties to select the appropriate varieties for extrusion processing.


Assuntos
Manipulação de Alimentos/métodos , Lens (Planta) , Sementes/química , Fenômenos Químicos , Temperatura Baixa , Manipulação de Alimentos/instrumentação , Indústria Alimentícia , Lens (Planta)/classificação , Solubilidade , Especificidade da Espécie , Amido , Temperatura , Viscosidade
4.
Food Microbiol ; 95: 103677, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33397611

RESUMO

Imported papayas from Mexico have been implicated in multiple salmonellosis outbreaks in the United States in recent years. While postharvest washing is a critical process to remove latex, dirt, and microbes, it also has the potential of causing cross-contamination by foodborne pathogens, with sponge or other fibrous rubbing tools often questioned as potential harboring or transmitting risk. In this study, Salmonella inactivation and cross-contamination via sponges and microfiber wash mitts during simulated papaya washing and cleaning were investigated. Seven washing treatments (wash without sanitizer; wash at free chlorine 25, 50, and 100 mg/L, and at peracetic acid 20, 40, and 80 mg/L), along with unwashed control, were evaluated, using Salmonella strains with unique antibiotic markers differentially inoculated on papaya rind (serovars Typhimurium, Heidelberg, and Derby) and on wash sponge or microfiber (serovars Typhimurium, Newport, and Braenderup). Salmonella survival and transfer on papaya and on sponge/microfiber, and in wash water were detected using selective plating or enrichment. The washing and cleaning process reduced Salmonella on inoculated papayas by 1.69-2.66 and 0.69-1.74 log for sponge and microfiber cleaning, respectively, with the reduction poorly correlated to sanitizer concentration. Salmonella on inoculated sponge or microfiber was under detection limit (1.00 log CFU/cm2) by plate count, but remained recoverable by selective enrichment. Transference of Salmonella from inoculated papaya to sponge/microfiber, and vice versa, could be detected sporadically by selective enrichment. Sponge/microfiber mediated Salmonella cross-contamination from inoculated to uninoculated papayas was frequently detectable by selective enrichment, but rendered undetectable by wetting sponge/microfiber in sanitizing wash water (FC 25-100 mg/L or PAA 20-80 mg/L) between washing different papaya fruits. Therefore, maintaining adequate sanitizer levels and frequently wetting sponge/microfiber in sanitizing wash water can effectively mitigate risks of Salmonella cross-contamination associated with postharvest washing, especially with regard to the use of sponge or microfiber wash mitts.


Assuntos
Carica/microbiologia , Cloro/farmacologia , Desinfetantes/farmacologia , Manipulação de Alimentos/instrumentação , Ácido Peracético/farmacologia , Poríferos/microbiologia , Salmonella typhimurium/efeitos dos fármacos , Animais , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Frutas/microbiologia , México , Salmonella typhimurium/crescimento & desenvolvimento
5.
Food Microbiol ; 95: 103705, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33397623

RESUMO

Amplicon sequencing approaches have been widely used in food bacterial ecology. However, choices regarding the methodology can bias results. In this study, bacterial communities associated with cold-smoked salmon products and their processing plant surfaces were monitored via sequencing of the V3-V4 region of the 16S rRNA gene. The impact of DNA extraction protocols, sampling methods (swabbing or sponging) and surface materials on bacterial communities were investigated. α and ß diversity analyses revealed that DNA extraction methods mainly influence the observed cold-smoked salmon microbiota composition. Moreover, different DNA extraction methods revealed significant differences in observed community richness and evenness. ß-Proteobacteria: Photobacterium, Serratia and Firmicutes: Brochothrix, Carnobacterium and Staphylococcus were identified as the dominant genera. Surface microbiota richness, diversity and composition were mainly affected by cleaning and disinfection procedures but not by DNA extraction methods. Surface community richness and evenness appeared higher when sampled by sponging compared to swabbing. ß-diversity analyses highlighted that surface topology, cleaning and disinfection and sampling devices seemed to affect the bacterial community composition. The dominant surface bacteria identified were mainly Flavobacteriaceae, ß-Proteobacteria and γ-Proteobacteria described as fish spoilers such as Acinetobacter, Pseudomonas and Shewanella. DNA extraction and sampling methods can have an impact on sequencing results and the ecological analysis of bacterial community structures. This study confirmed the importance of methodology standardization and the need for analytical validation before 16S rDNA metabarcoding surveys.


Assuntos
Bactérias/isolamento & purificação , DNA Bacteriano/isolamento & purificação , Produtos Pesqueiros/microbiologia , Técnicas Genéticas , Microbiota , RNA Ribossômico 16S/isolamento & purificação , Salmão/microbiologia , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , DNA Bacteriano/genética , DNA Ribossômico/genética , DNA Ribossômico/isolamento & purificação , Manipulação de Alimentos/instrumentação , RNA Ribossômico 16S/genética
6.
Food Chem ; 335: 127651, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32739817

RESUMO

We establish the total amino acids (AA) concentration in wash water as an alternative indicator of free chlorine (FC) levels, and develop a model to predict FC concentration based on modeling the reaction kinetics of chlorine and amino acids. Using single wash of iceberg lettuce, green cabbage, and carrots, we report the first in situ apparent reaction rate ß between FC and amino acids in the range of 15.3 - 16.6 M-1 s-1 and an amplification factor γ in the range of 11.52-11.94 for these produce. We also report strong linear correlations between AA levels and produce-to-water ratio (R2 = 0.87), and between chemical oxygen demand (COD) and AA concentrations (R2 = 0.87). The values of the parameters γ and ß of the model were validated in continuous wash experiments of chopped iceberg lettuce, and predicted the FC (R2 = 0.96) and AA (R2 = 0.92) levels very well.


Assuntos
Aminoácidos/análise , Brassica/química , Cloro/análise , Daucus carota/química , Desinfetantes/análise , Manipulação de Alimentos/instrumentação , Alface/química , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Microbiologia de Alimentos
7.
J Sci Food Agric ; 101(1): 74-81, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32609872

RESUMO

BACKGROUND: The consumption of vegetable juices has increased due to their characteristics such as freshness/naturalness, high nutritional value, low in calories, and for being a convenient way of consuming bioactive compounds. High hydrostatic pressure (HPP), which has been mainly used to replace thermal processing, is now also being successfully applied as extraction technology to recover bioactive compounds from herbs. The present work aimed to evaluate the effect of supplementation of carrot juice with winter savory leaf aqueous extract on the final juice characteristics. RESULTS: The extract was added to raw carrot juice (1.0 mg mL-1 ), which was then submitted to HPP and stored for 15 days under refrigeration. Microbial analyses were performed during storage time, as also were analyzed the physicochemical properties such as pH, colour, bioactive compound concentration and antioxidant activity. Supplemented juices presented lower microbial counts than the non-supplemented ones, and, generally, did not present significant changes (P > 0.05) in pH or colour. Concerning the total phenolics and total flavonoids, as well as antioxidant activity, the values were generally higher (P < 0.05) in supplemented juices, which was proven by the high correlation found between total phenolics and ABTS●+ and FRAP assays. CONCLUSIONS: These data suggest that the addition of winter savory leaf extract in carrot juice treated with HPP can effectively improve microbial safety throughout refrigerated storage as well as antioxidant activity, without risking other characteristics of the juice, such as the colour or the acidity. © 2020 Society of Chemical Industry.


Assuntos
Daucus carota/química , Aditivos Alimentares/análise , Conservação de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Extratos Vegetais/análise , Satureja/química , Antioxidantes/análise , Manipulação de Alimentos/instrumentação , Manipulação de Alimentos/métodos , Concentração de Íons de Hidrogênio , Pressão Hidrostática , Valor Nutritivo , Folhas de Planta/química
8.
J Sci Food Agric ; 101(1): 167-178, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32613616

RESUMO

BACKGROUND: Peas are an inexpensive yet nutritious and sustainable source of protein. However, it is challenging to incorporate pea proteins into food formulations owing to their beany or green off-flavours and their limited water solubility. RESULTS: Vacuum microwave dehydration (VMD) of pea protein with an initial moisture content of 425% (dry basis, db) at 2 W g-1 specific microwave energy and 200 Torr vacuum level for 88 min led to an 83% reduction in total volatile compound concentration. VMD processing at high initial moisture contents facilitated the Maillard reaction, enhancing the extent of protein cross-linking, leading to a marked decrease in soluble protein content, to 11 g kg-1 . Reducing the initial moisture content to 56% db greatly retained protein solubility (112-113 g kg-1 ), but it only led to a minor reduction in total volatile compound concentration (2-11% reduction). A high microwave energy (20 W g-1 )-short time (2 min) treatment at 200 Torr vacuum level was found optimal, reducing both volatile levels and soluble protein content by ~50%. CONCLUSION: Evidently, it is difficult to employ VMD without reduction of pea protein solubility and corresponding changing in functionality. Yet, if optimized, VMD has the capability to decrease volatile concentrations while retaining protein solubility. Future sensory analysis should be conducted to determine whether the aforementioned reductions in total volatile compound concentration may have a notable effect on consumer palatability. © 2020 Society of Chemical Industry.


Assuntos
Dessecação/métodos , Manipulação de Alimentos/métodos , Ervilhas/efeitos da radiação , Proteínas de Plantas/química , Sementes/química , Dessecação/instrumentação , Aromatizantes/química , Manipulação de Alimentos/instrumentação , Micro-Ondas , Ervilhas/química , Sementes/efeitos da radiação , Vácuo
9.
J Sci Food Agric ; 101(2): 347-363, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32564354

RESUMO

The central kitchen concept is a new trend in the food industry, where centralized preparation and processing of fresh foods and the distribution of finished or semi-finished products to catering chains or related units take place. Fresh foods processed by a central kitchen mainly include fruit and vegetables, meat, aquatic products, and edible fungi; these foods have high water activities and thermal sensitivities and must be processed with care. Appropriate pretreatments are generally required for these food materials; typical pretreatment processes include cleaning, enzyme inactivation, and disinfection, as well as packaging and coating. To improve the working efficiency of a central kitchen, novel efficient pretreatment technologies are needed. This article systematically reviews various high-efficiency pretreatment technologies for fresh foods. These include ultrasonic cleaning technologies, physical-field enzyme inactivation technologies, non-thermal disinfection technologies, and modified-atmosphere packagings and coatings. Mechanisms, applications, influencing factors, and advantages and disadvantages of these technologies, which can be used in a central kitchen, are outlined and discussed. Possible solutions to problems related to central-kitchen food processing are addressed, including low cleaning efficiency and automation feasibility, high nutrition loss, high energy consumption, and short shelf life of products. These should lead us to the next step of fresh food processing for a highly demanding modern society. © 2020 Society of Chemical Industry.


Assuntos
Manipulação de Alimentos/métodos , Frutas/química , Carne/análise , Verduras/química , Animais , Manipulação de Alimentos/instrumentação , Manipulação de Alimentos/normas , Qualidade dos Alimentos , Humanos
10.
J Sci Food Agric ; 101(2): 398-413, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32627847

RESUMO

BACKGROUND: Combined infrared (CIR) and convective drying is a promising technology in dehydrating heat-sensitive foods, such as fruits and vegetables. This novel thermal drying method, which involves the application of infrared energy and hot air during a drying process, can drastically enhance energy efficiency and improve overall product quality at the end of the process. Understanding the dynamics of what goes on inside the product during drying is important for further development, optimization, and upscaling of the drying method. In this study, a multiphase porous media model considering liquid water, gases, and solid matrix was developed for the CIR and hot-air drying (HAD) of sweet potato slices in order to capture the relevant physics and obtain an in-depth insight on the drying process. The model was simulated using Matlab with user-friendly graphical user interface for easy coupling and faster computational time. RESULTS: The gas pressure for CIR-HAD was higher centrally and decreased gradually towards the surface of the product. This implies that drying force is stronger at the product core than at the product surface. A phase change from liquid water to vapour occurs almost immediately after the start of the drying process for CIR-HAD. The evaporation rate, as expected, was observed to increase with increased drying time. Evaporation during CIR-HAD increased with increasing distance from the centreline of the sample surface. The simulation results of water and vapour flux revealed that moisture transport around the surfaces and sides of the sample is as a result of capillary diffusion, binary diffusion, and gas pressure in both the vertical and horizontal directions. The nonuniform dominant infrared heating caused the heterogeneous distribution of product temperature. These results suggest that CIR-HAD of food occurs in a non-uniform manner with high vapour and water concentration gradient between the product core and the surface. CONCLUSIONS: This study provides in-depth insight into the physics and phase changes of food during CIR-HAD. The multiphase model has the advantage that phase change and impact of CIR-HAD operating parameters can be swiftly quantified. Such a modelling approach is thereby significant for further development and process optimization of CIR-HAD towards industrial upscaling. © 2020 Society of Chemical Industry.


Assuntos
Dessecação/métodos , Manipulação de Alimentos/métodos , Ipomoea batatas/química , Tubérculos/química , Dessecação/instrumentação , Manipulação de Alimentos/instrumentação , Temperatura Alta , Raios Infravermelhos , Ipomoea batatas/efeitos da radiação , Tubérculos/efeitos da radiação
11.
J Sci Food Agric ; 101(2): 424-432, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32648588

RESUMO

BACKGROUND: Pesticides have been widely used to control pests on agricultural products in China, and large amounts of pesticide residues have caused a serious threat to human health. Thus, developing a high-efficiency pesticide degradation method for fresh vegetables represents a great challenge. The present study investigated the effects of dielectric barrier discharge (DBD) plasma on the degradation of malathion and chlorpyrifos in aqueous solutions and on lettuces. RESULTS: DBD treatment significantly degraded malathion and chlorpyrifos in water and on lettuce. After cold plasma treatment at 80 kV for 180 s, the degradation efficiency of malathion (0.5 µg mL-1 ) and chlorpyrifos (1.0 µg mL-1 ) in aqueous solutions reached 64.6% and 62.7%, respectively. The degradation intermediates were explored by HPLC-mass spectrometry and the DBD plasma degradation pathways of malathion and chlorpyrifos were proposed. There was no significant damage to the quality of lettuces, including color and chlorophyll content, after plasma treatment. Ascorbic acid decreased significantly during long-term treatment with DBD plasma. To ensure the quality of lettuces during processing, the treatment time was shortened to 120 s. Under this condition, the degradation efficiency of malathion (0.5 mg kg-1 ) and chlorpyrifos (1.0 mg kg-1 ) on lettuces was found to be 53.1% and 51.4%. More importantly, we noted that cold plasma treatment significantly inactivated the microorganisms on lettuces. CONCLUSION: The results of the present study show that cold plasma is an effective and safe method for the degradation of organic pesticide residues on fresh vegetables at the same time as retaining the original quality. © 2020 Society of Chemical Industry.


Assuntos
Clorpirifos/química , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Alface/efeitos dos fármacos , Malation/química , Resíduos de Praguicidas/química , Folhas de Planta/química , Gases em Plasma/farmacologia , Contaminação de Alimentos/análise , Manipulação de Alimentos/instrumentação , Cinética , Alface/química , Folhas de Planta/efeitos da radiação , Poluentes Químicos da Água/química
12.
Food Microbiol ; 94: 103646, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33279071

RESUMO

Seaweeds are highly perishable foods due to their richness in nutrients. High pressure processing (HPP) has been applied for extending the shelf life of fresh seaweeds but there is no information on the effect of HPP on the bacterial diversity of seaweeds. The culturable bacteria of six species of fresh edible seaweeds (green seaweeds Codium fragile and Ulva lactuca, brown seaweeds Himanthalia elongata, Laminaria ochroleuca and Undaria pinnatifida, and red seaweed Chondrus crispus) were investigated and compared to those of HPP-treated (400 and 600 MPa for 5 min) seaweeds, at the start and end of their refrigerated storage period. A total of 523 and 506 bacterial isolates were respectively retrieved from untreated and HPP-treated seaweeds. Isolates from untreated seaweeds belonged to 18 orders, 35 families, 71 genera and 135 species whereas isolates from HPP-treated seaweeds belonged to 13 orders, 23 families, 43 genera and 103 species. HPP treatment significantly reduced the number of isolates belonging to 6 families and greatly increased the number of Bacillaceae isolates. At the end of storage, decreases in bacterial diversity at the genus and species level were observed for untreated as well as for HPP-treated seaweeds.


Assuntos
Bactérias/isolamento & purificação , Biodiversidade , Clorófitas/microbiologia , Alga Marinha/microbiologia , Bactérias/química , Bactérias/classificação , Bactérias/genética , Manipulação de Alimentos/instrumentação , Manipulação de Alimentos/métodos , Manipulação de Alimentos/estatística & dados numéricos , Armazenamento de Alimentos , Verduras/microbiologia
13.
Food Microbiol ; 94: 103645, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33279070

RESUMO

As a consequence of developing antimicrobial resistance to disinfectants, copper, which exhibits antimicrobial activity, has been studied as a possible alternative to the use of stainless steel surfaces. The aim was to evaluate the antimicrobial activity of copper surfaces in preventing biofilm formation by Salmonella Enteritidis and to determine their corrosive capacity. Strains of S. Enteritidis were incubated at 4 °C, 12 °C, and 25 °C with 1 cm2 coupons of electrolytic copper (99.9% Cu), brass (70% Cu), copper coated with tin, and stainless steel (control). A planktonic cell-suspension assay was used, followed by serial dilutions and bacterial counts. The corrosion test was performed with two disinfectants: benzalkonium chloride and sodium hypochlorite (100, 200, and 400 ppm). There was a significant reduction in biofilm production (log10 CFU cm-2) on the copper (2.64 at 4 °C, 4.20 at 12 °C, 4.56 at 25 °C) and brass (2.79 at 4 °C, 3.49 at 12 °C, 4.55 at 25 °C) surfaces compared to the control (5.68 at 4 °C, 5.89 at 12 °C, 6.01 at 25 °C). The antimicrobial surfaces showed uniform corrosion similar to that of surfaces generally used. These results demonstrated the effectiveness of copper surfaces in reducing S. Enteritidis and suggest they can be used as a complementary antimicrobial to control for this pathogen.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Cobre/farmacologia , Desinfetantes/farmacologia , Manipulação de Alimentos/instrumentação , Salmonella enteritidis/efeitos dos fármacos , Animais , Cobre/análise , Contaminação de Equipamentos/prevenção & controle , Aves Domésticas , Salmonella enteritidis/crescimento & desenvolvimento , Salmonella enteritidis/fisiologia , Aço Inoxidável/análise , Zinco/análise
14.
Food Microbiol ; 94: 103648, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33279073

RESUMO

Shelf life of red meat is influenced by a number of intrinsic and extrinsic factors making its prediction challenging. Here we investigated the influence of geographically distant abattoir facilities and storage temperature relevant to commercial supply chain on the shelf lives of vacuum packaged (VP) beef and lamb meat. Samples of VP beef and lamb were analysed for surface pH, total viable counts, lactic acid bacterial counts, sensory properties, and associated bacterial community using Illumina MiSeq based 16S rRNA gene amplicon sequencing over a period of >200 days. The consistent 0.41 pH unit difference between beef and lamb was found to have a profound effect on bacterial community diversity and composition, bacterial growth rates and the rate of loss of sensory quality. Though different community structures were derived from different abattoir source, bacterial growth rate and rate of sensory quality deterioration were found to be comparable for individual meat type. The greatest variation in rates was found resulting from storage temperature and livestock species themselves. Our findings indicate that bacterial growth and sensory quality loss are essentially predictable when considering their temperature dependency, however for successful meat export validation of shelf life predictive models is required due to stochastic variation in abattoir seeded bacterial populations.


Assuntos
Bactérias/isolamento & purificação , Bovinos/microbiologia , Carne/microbiologia , Microbiota , Ovinos/microbiologia , Matadouros/estatística & dados numéricos , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Contaminação de Alimentos/estatística & dados numéricos , Manipulação de Alimentos/instrumentação , Microbiologia de Alimentos , Embalagem de Alimentos/instrumentação , Embalagem de Alimentos/métodos , Humanos , Paladar , Temperatura , Vácuo
15.
Food Microbiol ; 94: 103667, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33279090

RESUMO

Production of leafy vegetables for the "Ready-to-eat"-market has vastly increased the last 20 years, and consumption of these minimally processed vegetables has led to outbreaks of food-borne diseases. Contamination of leafy vegetables can occur throughout the production chain, and therefore washing of the produce has become a standard in commercial processing. This study explores the bacterial communities of spinach (Spinacia oleracea) and rocket (Diplotaxis tenuifolia) in a commercial setting in order to identify potential contamination events, and to investigate effects on bacterial load by commercial processing. Samples were taken in field, after washing of the produce and at the end of shelf-life. This study found that the bacterial community composition and diversity changed significantly from the first harvest to the end of shelf-life, where the core microbiome from the first to the last sampling constituted <2% of all OTUs. While washing of the produce had no reducing effect on bacterial load compared to unwashed, washing led to a change in species composition. As the leaves entered the cold chain after harvest, a rise was seen in the relative abundance of spoilage bacteria. E. coli was detected after the washing indicating issues of cross-contamination in the wash water.


Assuntos
Bactérias/isolamento & purificação , Brassicaceae/microbiologia , Manipulação de Alimentos/métodos , Spinacia oleracea/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Carga Bacteriana , Contaminação de Alimentos/análise , Manipulação de Alimentos/instrumentação , Água Doce/microbiologia , Folhas de Planta/microbiologia , Verduras/microbiologia
16.
PLoS One ; 15(9): e0239564, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956385

RESUMO

Palegawra cave, alongside its neighbouring Zarzi, has been an emblematic site of the Epipalaeolithic (Zarzian) cultural horizon in the NW Zagros of Southwest Asia ever since its first exploration in 1951 by Bruce Howe and Robert Braidwood in the context of the Iraq-Jarmo project. At the time scientific excavation, sampling and analysis methods were either under-developed or did not exist. In this paper we present the first results of new excavations at Palegawra conducted in 2016-2017 by the Eastern Fertile Crescent (EFEC) project, a research collaboration of the University of Liverpool and the Sulaymaniyah Directorate of Antiquities and Heritage. Our research has produced the first radiometric evidence pushing back the chronology of the NW Zagros Epipalaeolithic to the Last Glacial Maximum, thus fully aligning it with Epipalaeolithic facies until now known only from the Levant and the south Anatolian coast. We have also unearthed, for the first time in the Palaeolithic of the Zagros, direct archaeobotanical evidence for hitherto elusive Zarzian plant exploitation and the vegetation of the NW Zagros piedmont zone from the LGM to the end of the Lateglacial (~19,600-13,000 cal BP). The new Palegawra chronology alongside our detailed studies of its material culture and faunal and botanical assemblages suggest that the prevailing Epipalaeolithic habitation pattern in the NW Zagros (centred on generalised persistent occupations of small caves and rock-shelters alongside task-oriented ephemeral open-air campsites) remained an enduring characteristic of the Zarzian horizon throughout this period. The Palegawra data clearly show that neither resource levels and climate conditions nor geographic and/or cultural isolation provide adequate explanations for the stability and longevity of Zarzian lifeways during this long timespan. More fieldwork is required, including the discovery, excavation and intensive sampling of other Zarzian sites, for reaching a data-informed understanding of the nature and evolution of the NW Zagros Epipalaeolithic.


Assuntos
Arqueologia/métodos , Agricultura/história , Animais , Antropologia Cultural , Artiodáctilos , Carnivoridade , Cavernas , Carvão Vegetal , Clima , Manipulação de Alimentos/história , Manipulação de Alimentos/instrumentação , Fósseis , Geografia , Herbivoria , História Antiga , Humanos , Iraque , Plantas , Datação Radiométrica , Armas/história
17.
J Food Sci ; 85(9): 2879-2888, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32839999

RESUMO

Ultrasound-assisted freezing (UF) has proven to be a method that can effectively increase the freezing rate of frozen food and improve its quality. The functional properties of myofibrillar proteins (MP) are important factors that affect the further processing quality of meat products. At present, the effect of UF on the functional properties of frozen MP is not yet clear. Therefore, in the present study, changes in the functional properties (emulsifying and gel properties) of MP in common carps (Cyprinus carpio) frozen with UF at different power levels were investigated. The results revealed that, compared with immersion freezing (IF), UF at 175 W (UF-175) effectively inhibited the decrease in protein solubility, absolute Zeta potential, emulsion activity index, storage modulus (G'), and loss modulus (G'') caused by freezing. UF-175 sample had lower protein turbidity, and smaller protein particle size than any other frozen samples (P < 0.05), which suggested that UF-175 inhibited protein aggregation induced by freezing. In addition, shorter T21 and T22 relaxation times were obtained in UF-175 sample than other frozen samples, indicating that UF-175 reduced the mobility of immobilized and free water. Accordingly, UF-175 sample had higher gel strength and water holding capacity than other frozen samples (P < 0.05). A denser and more uniform gel network structure was also found in UF-175 sample than other frozen samples. In general, improved functional properties of common carp MP can be achieved by optimal UF.


Assuntos
Proteínas de Peixes/química , Manipulação de Alimentos/métodos , Produtos da Carne/análise , Proteínas Musculares/química , Animais , Carpas , Emulsões/química , Manipulação de Alimentos/instrumentação , Congelamento , Tamanho da Partícula , Ultrassom
18.
Ecotoxicol Environ Saf ; 201: 110729, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32485491

RESUMO

The transformation of carbosulfan (CSN) in apples was investigated during oven-drying, microwave drying, and sun-drying. CSN transformed primarily into carbofuran (COA) during these drying processes. The conversion kinetics of CSN and COA was fitted by curve regression and mainly conformed to quadratic models (R2 = 0.70-0.97). Oven-drying promoted the transformation of CSN into COA. Microwave drying resulted in the highest scavenging capacity against CSN and COA (41%-100%). Moreover, a transformation mechanism was proposed on the basis of density functional theory (DFT) calculation. The COA originated from a series of chemical reactions involving hydroxyl substitution, cleavage, and oxidation; this result was further confirmed on the basis of molecular electrostatic potential (MEP) and molecular orbital theory. Furthermore, the toxicity and stability of CSN and COA were evaluated with the T.E.S.T. program. COA was less toxic than CSN to aquatic organisms but more toxic than CSN to rats. Therefore, COA production should be avoided during drying. Microwave drying was found to be the optimum choice for drying apples.


Assuntos
Carbamatos/metabolismo , Dessecação/métodos , Manipulação de Alimentos/métodos , Malus/química , Animais , Organismos Aquáticos/efeitos dos fármacos , Carbamatos/química , Carbamatos/toxicidade , Carbofurano/química , Carbofurano/metabolismo , Carbofurano/toxicidade , Dessecação/instrumentação , Manipulação de Alimentos/instrumentação , Sequestradores de Radicais Livres/análise , Ratos
19.
J Food Sci ; 85(5): 1479-1488, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32395876

RESUMO

The technique for order performance by similarity to ideal solution (TOPSIS) method was used to select the optimum point of power and time of ultrasound and baking temperature of eggless cake production. The effect of ultrasound power and baking time on the mass-transfer parameters such as moisture diffusion and the activation energy was assessed. The sonication treatment increased the viscosity of the eggless cake batter (25% in consistency coefficient and 24% in apparent viscosity). The minimum batter density was observed at 60% intensity for 30 or 60 s of sonication (1.0253 and 1.027 g/cm3 ). This condition also increased the eggless cake volume and springiness. In contrast, the crumb fractal dimension, hardness, gumminess, cohesiveness, and chewiness of the eggless cake decreased (1.65, 29, 39, 39, and 33%, respectively). The moisture diffusion during baking at 160, 180, and 200 °C and different ultrasound intensities were studied. The baking temperature of 200 °C and the intensity of 60% had the maximum effect on increasing the moisture diffusivity. Arrhenius equation showed the activation energy varied from 21.38 to 22.95 kJ/mol. The optimum quality of the eggless cake resulted from a combination of 60% intensity and 60 s of sonication and the baking temperature of 180 °C. PRACTICAL APPLICATION: Some vegetarians do not consume eggs and egg-based products; therefore it is important to produce egg-free food options. Also, considering that eggs are one of the most expensive raw materials in the production of various types of cakes and have a low shelf-life, in this study, the effects of sonication on the quality characteristics of an eggless cake has been studied.


Assuntos
Pão/análise , Manipulação de Alimentos/métodos , Odorantes/análise , Animais , Galinhas , Culinária , Ovos/análise , Análise de Alimentos , Manipulação de Alimentos/instrumentação , Dureza , Temperatura Alta , Sonicação , Viscosidade
20.
J Food Sci ; 85(5): 1386-1396, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32333397

RESUMO

Ultrasound (US) is classified as a nonthermal treatment and it is used in food processing at a frequency range between 20 kHz and 1 MHz. Cavitation bubbles occur when the US strength is high enough to generate rarefaction that exceeds the intermolecular attraction forces in the medium. Currently, US is widely used in meat industries to enhance procedures, such as meat tenderization, emulsification mass transfer, marination, freezing, homogenization, crystallization, drying, and microorganism inactivation. In addition, combining ultrasonic energy with a sanitizing agent has a synergistic effect on microbial reduction. When poultry meat is treated using US, the expected quality is often better than the traditional methods, such as sanitization and freezing. US can be considered as a novel green technology for tenderizing and decontamination of poultry meat since both Escherichia coli and Salmonella are sensible to US. US improves the physical and chemical properties of meat proteins and can lead to a decrease in the α-helix in intramuscular protease complex in addition to a reduction in the viscosity coefficients. Therefore, ultrasonic treatment can be applied to enhance the textural properties of chicken meat. US can also be used to improve the drying rate when used under vacuum, compared with other traditional techniques. This review focuses on the potential of US applications in the management of poultry industries as the demand for good quality meat proteins is increasing worldwide.


Assuntos
Manipulação de Alimentos/métodos , Carne/análise , Ultrassom/métodos , Animais , Manipulação de Alimentos/instrumentação , Congelamento , Aves Domésticas , Salmonella/genética , Salmonella/isolamento & purificação , Ultrassom/instrumentação , Vácuo
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