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1.
Food Chem ; 338: 127822, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32810813

RESUMO

In this study, a potential of covalent linkage approach for developing active edible coatings was examined. Vanillin and trans-cinnamaldehyde were bound to chitosan by Schiff base reaction and reductive amination. The modified polysaccharides were comprehensively characterized and applied as active coatings on fresh-cut melon. The covalent linkage allowed overcoming solubility problems with the lipophilic vanillin and cinnamaldehyde and neutralizing their volatility, producing well-adhered coatings that enhanced fruit quality and storability without sensorial impairment. The attached hydrophobic moieties also provided new polysaccharides with self-assembling ability. Their aggregates were loaded with antimicrobial citral and added to mandarin juice, resulting in up to 6 log CFU/mL microbial count reduction. Thus, the covalent linkage concept offers several advantages, especially when hydrophobic or volatile active agents are used. Further developed, it may become a safe and effective tool for the formation of advanced active edible coatings and delivery vehicles for direct applications on food products.


Assuntos
Acroleína/análogos & derivados , Benzaldeídos/química , Filmes Comestíveis , Polissacarídeos/química , Acroleína/química , Monoterpenos Acíclicos/química , Anti-Infecciosos/química , Quitosana/química , Citrus , Cucurbitaceae/metabolismo , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Armazenamento de Alimentos , Frutas/metabolismo , Sucos de Frutas e Vegetais/microbiologia , Interações Hidrofóbicas e Hidrofílicas
2.
Food Chem ; 335: 127647, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32739816

RESUMO

The inhibition mechanism of the texture deterioration of tilapia fillets after treatment with polyphenols during partial freezing for 49 days was studied. Carnosic acid (CA), procyanidin (PA), quercetin (QE), and resveratrol (RSV) treatments had significantly higher hardness values (over 230 g) than the control group (183 g) on day 49 (P < 0.05). Polyphenol treatments were effective in delaying the protein degradation, lipid oxidation and spoilage microbe growth. Moreover, the kinetic model showed that the predicted shelf life of tilapia fillets treated with PA (102 d) was extended by 25 d compared to the control group (77 d). It was the proposed possible mechanism that polyphenols comprehensively maintained the protein conformation (increased hydrogen bonds and decreased disulfide bonds) and retarded protein denaturation and degradation, protecting the texture of the fillets. Therefore, polyphenols can be used to maintain texture and extend the shelf life of tilapia fillets during partial freezing.


Assuntos
Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Carne/análise , Polifenóis/análise , Polifenóis/farmacologia , Animais , Biflavonoides/química , Catequina/química , Proteínas de Peixes/química , Conservação de Alimentos/instrumentação , Congelamento , Oxirredução/efeitos dos fármacos , Proantocianidinas/química , Desnaturação Proteica/efeitos dos fármacos , Tilápia
3.
Anim Sci J ; 91(1): e13466, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33043554

RESUMO

Sremski kulen is a wide diameter dry fermented sausage, produced from pork, seasoned with red spicy paprika, stuffed into pork cecum, and preserved by smoking, fermentation and drying. Due to specific ripening process, Sremski kulen is suitable for the accumulation of biogenic amines. Therefore, the aminogenesis was studied in traditionally produced Sremski kulen, taking into account the physicochemical parameters and microbial counts. The content of six biogenic amines (tryptamine, phenylethylamine, tyramine, histamine, putrescine, and cadaverine) was analyzed using high-performance liquid chromatography. The ripening process of Sremski kulen was slow followed by changes in aw and pH value as well as expressed proteolysis. The autochthonous microbiota showed pronounced decarboxylase activity. Tryptamine and phenylethylamine were detected at each examined ripening stage while histamine was not detected until the end of ripening (16.55 ± 2.33 mg/kg). Tyramine, cadaverine, and putrescine content significantly increased during the ripening period (p < .05). In the final product, cadaverine was the dominant biogenic amine (132.40 ± 5.05 mg/kg), followed by tyramine (115.80 ± 15.46 mg/kg) and putrescine (68.55 ± 2.39 mg/kg). Although the long ripening period greatly contributed to the accumulation of biogenic amines in final product, their content are not of concern from product safety aspects, but requires improvement in hygiene of production process.


Assuntos
Aminas Biogênicas/análise , Fermentação , Análise de Alimentos/métodos , Manipulação de Alimentos/métodos , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Produtos da Carne/análise , Carne de Porco , Animais , Cadaverina/análise , Fenômenos Químicos , Cromatografia Líquida de Alta Pressão , Microbiologia de Alimentos , Inocuidade dos Alimentos , Concentração de Íons de Hidrogênio , Produtos da Carne/microbiologia , Proteólise , Putrescina/análise , Suínos , Tiramina/análise
4.
Anim Sci J ; 91(1): e13354, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32789990

RESUMO

The study was aimed to investigate the influence of animal age, post-slaughter chilling rate, and aging time on meat quality of M. longissimus dorsi (LD) of water buffalo (Bubalus bubalis) and humped cattle (Bos taurus indicus) bulls. After slaughtering, one side of carcasses was subjected to rapid chilling (RC) (0 ± 2°C) and other side was hanged in controlled room temperature (25 ± 2°C) for 3 hr, then allowed to the chiller (0 ± 2°C). The meat quality traits were analyzed at 1, 7, and 14 days of storage. It was noted that rapidly chilled carcasses from the younger animals of both species missed the ideal pH/temperature window, which affects the toughness of the meat. Buffalo meat presented higher shear force, color L* values, and lower b* value as compared to the cattle meat. Moreover, meat shear force values decreased while all color coordinates and cooking loss values increased with lengthening the storage time in both age groups of cattle and buffalo. In conclusion, the tenderness of cattle meat was superior to that of buffalo and RC adversely affect the shear force values of young cattle and both age groups of buffalo bulls.


Assuntos
Temperatura Baixa , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Carne Vermelha , Envelhecimento , Animais , Búfalos , Bovinos , Temperatura Baixa/efeitos adversos , Masculino , Fatores de Tempo
5.
Int J Food Microbiol ; 332: 108811, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-32835914

RESUMO

The aim of this study was to evaluate a hurdle strategy for orange-tangerine (OT) and orange-banana-mango-kiwi-strawberry (OBMKS) juices processing based on UV-C treatment assisted or not by mild heat and the addition of natural antimicrobials. Vanillin and citral emulsions were successfully encapsulated using maltodextrin and HI-CAP (5,18,3) and characterized. The susceptibility of Lactobacillus plantarum ATCC 8014, Escherichia coli ATCC 25922, and Saccharomyces cerevisiae KE 162 to binary mixtures of the encapsulated agents was examined in culture media according to the Berenbaum experimental design. The boundary between growth and non-growth as a function of vanillin and citral concentrations was predicted by means of the probabilistic model using logistic regression. Microbial inactivation achieved by pilot-scale UV-C light (0-390 mJ/cm2) on its own, assisted by mild heat (50 °C, UV-C/H) and combined with antimicrobials (1000 ppm vanillin plus 100 ppm citral) addition (UV-C + A/UV-C/H + A) was assessed in OT and OBMKS. Yeast induced damage in a model solution treated by UV-C + A was studied by flow cytometry (FC). All the antimicrobial mixtures resulted in additive effects (FICindex = 1), thus offering through the probabilistic models a range of formulation possibilities with antimicrobial capacity encompassing lower vanillin and citral concentrations compared to those required when used alone (Vrange = 0-1875 ppm plus Crange = 392-0 ppm). UV-C led up to 3.7-3.8, 2.4-3.6 and 1.5-1.6 log-reductions of E. coli, L. plantarum and S. cerevisiae in OT and OBMKS, respectively. A significant increase of 1.7-2.2, 2.1-2.7 and 4.1-5.3 log cycles in microbial inactivation was observed after UV-C/H treatment. Additional inactivation of 0.7-3.1 and 0.5-2.7 log reductions were observed for E. coli and S. cerevisiae, respectively, when UV-C + A and UV-C/H + A were applied in both juices. Therefore, the addition of antimicrobials to the UV-C treated juices, showed additive to synergistic effects on E. coli and S. cerevisiae, respectively along refrigerated storage. A shift from yeast cells with intact membrane and esterase activity in control samples to cells with permeabilized membrane in C + A, UV-C and UV-C + A samples were determined by FC. The shift was more noticeable in UV-C + A samples. Sublethally damaged cells were only detected in C + A and UV-C samples. This study demonstrates that combining a pilot-scale UV-C treatment with the addition of chosen binary mixtures of vanillin and citral, can ensure more than 5 log-reductions of E. coli, L. plantarum and S. cerevisiae in OT and OBKMS juice blends.


Assuntos
Monoterpenos Acíclicos/farmacologia , Benzaldeídos/farmacologia , Conservação de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Raios Ultravioleta , Monoterpenos Acíclicos/química , Antibacterianos/química , Antibacterianos/farmacologia , Benzaldeídos/química , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Temperatura Alta , Viabilidade Microbiana/efeitos dos fármacos , Viabilidade Microbiana/efeitos da radiação
6.
Int J Food Microbiol ; 333: 108793, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-32763758

RESUMO

Listeria monocytogenes is a human pathogen that is commonly found in environments associated with cold-smoked salmon. Nisin is a natural antimicrobial that can be used as a food preservative. While nisin is active against a number of Gram-positive bacteria, including L. monocytogenes, environmental stresses encountered in cold-smoked salmon processing facilities might affect L. monocytogenes' nisin susceptibility. The objective of this study was to investigate the effect of seafood-relevant pre-growth conditions and L. monocytogenes strain diversity on nisin treatment efficacy on cold-smoked salmon. Six L. monocytogenes strains representing serotypes most commonly associated with cold-smoked salmon (1/2a, 1/2b, and 4b) were initially pre-grown under a number of seafood-relevant conditions and challenged with nisin in growth media modified to represent the characteristics of cold-smoked salmon. The pre-growth conditions with the lowest mean log reduction due to nisin and the highest strain-to-strain variability were selected for experiments on cold-smoked salmon; these included: (i) 4.65% w.p. NaCl ("NaCl"); (ii) pH = 6.1 ("pH"); (iii) 0.5 µg/ml benzalkonium chloride ("Quat"); and a control ("BHI"). Cold-smoked salmon slices with or without nisin were inoculated with L. monocytogenes pre-grown in one of the conditions above, vacuum-packed, and incubated at 7 °C. L. monocytogenes were enumerated on days 1, 15, and 30. A linear mixed effects model was constructed to investigate the effect of pre-growth condition, day in storage, serotype, source of isolation as well as their interactions on nisin efficacy against L. monocytogenes. Compared to pre-growth in "BHI", significant reduction (P < 0.05) in nisin efficacy was induced by pre-growth in "pH" and "Quat" on both days 15 and 30, and by pre-growth in "NaCl" on day 30, indicating a time-dependent cross-protection effect. Additionally, an effect of L. monocytogenes' serotype on the cross-protection to nisin was observed; pre-growth in "pH" significantly reduced nisin efficacy against serotype 1/2a and 4b strains, but not against 1/2b strains. In conclusion, pre-exposure to mildly acidic environment, high salt content, and sublethal concentrations of quaternary ammonium compounds, is likely to provide cross-protection against a subsequent nisin treatment of L. monocytogenes on cold-smoked salmon. Therefore, challenge studies that use pre-growth in "BHI", as well as more susceptible L. monocytogenes strains, may overestimate the efficacy of nisin as a control strategy for cold-smoked salmon.


Assuntos
Antibacterianos/farmacologia , Conservantes de Alimentos/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Nisina/farmacologia , Salmão/microbiologia , Animais , Contagem de Colônia Microbiana , Conservação de Alimentos/métodos , Humanos , Listeria monocytogenes/crescimento & desenvolvimento , Listeria monocytogenes/isolamento & purificação , Alimentos Marinhos/microbiologia
7.
Int J Food Microbiol ; 334: 108807, 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-32835997

RESUMO

The main goal of this study was to describe impact of preharvest application of methyl salicylate (MeSA), acetyl salicylic acid (ASA) and salicylic acid (SA) on the reduction of disease caused by Botrytis cinerea in two table grape cultivars ('Crimson' and 'Magenta'). Based on previous studies, MeSA and SA were applied at 0.1 and 0.01 mM for both cultivars, while ASA was applied at 1 mM in 'Crimson' and 0.1 mM in 'Magenta'. At time of harvest, berry maturity-quality attributes, bioactive compounds and antioxidant enzymes were determined. In addition, grapes were artificially inoculated with B. cinerea spores, and the berries were ranked for visual decay incidence after 5 days of inoculation. Salicylates preharvest treatments led to higher total acidity, content of bioactive compounds and activity of antioxidant enzymes in treated than in control berries. The application of salicylate derivatives induced resistance to B. cinerea spoilage, since higher percentage of berries with no symptoms was observed and on the contrary, the highest percentages of berries were obtained in control grapes. All preharvest treatments with SA, ASA and MeSA alleviated postharvest disease caused by B. cinerea probably due to increasing levels of phenolic compounds and activity of antioxidant enzymes, although the best results were obtained with MeSA at 0.1 mM. Also, for this treatment and dose, higher quality properties, such as higher concentrations of ascorbic, succinic and fumaric acids, were observed compared with no treated-grapes.


Assuntos
Antioxidantes/metabolismo , Botrytis/efeitos dos fármacos , Doenças das Plantas/prevenção & controle , Ácido Salicílico/farmacologia , Vitis/microbiologia , Aspirina/farmacologia , Resistência à Doença/efeitos dos fármacos , Conservação de Alimentos/métodos , Fenóis/metabolismo , Doenças das Plantas/microbiologia , Salicilatos/farmacologia , Vitis/efeitos dos fármacos , Vitis/metabolismo
8.
Food Chem ; 332: 127420, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32622191

RESUMO

The outbreaks of Cronobacter sakazakii, Salmonella spp, and Bacillus cereus in powdered foods have been increasing in worldwide. However, an effective method to pasteurize powdered foods before consumption remains lacking. A prototype Intense Pulsed Light (IPL) system was developed to disinfect powdered foods under different IPL and environmental conditions. Synergistic effect of IPL and TiO2 photocatalysis on microbial inactivation was studied. The results show that high energy intensity of each pulse, high peak intensity, and short pulsed duration contributed to a high microbe inactivation. With TiO2 photocatalysis, one additional log10 reduction was achieved, bringing the total log reduction to 4.71 ± 0.07 (C. sakazakii), 3.49 ± 0.01 (E. faecium), and 2.52 ± 0.10 (B. cereus) in non-fat dry milk, and 5.42 ± 0.10 (C. sakazakii), 4.95 ± 0.24 (E. faecium), 2.80 ± 0.23 (B. cereus) in wheat flour. IPL treatment combined with the TiO2 photocatalysis exhibits a strong potential to reduce the energy consumption in improving the safety of powdered foods.


Assuntos
Cronobacter sakazakii/efeitos da radiação , Cronobacter/efeitos da radiação , Farinha/microbiologia , Conservação de Alimentos/métodos , Viabilidade Microbiana/efeitos da radiação , Leite/microbiologia , Triticum/microbiologia , Animais , Bacillus cereus/crescimento & desenvolvimento , Bacillus cereus/efeitos da radiação , Cronobacter/crescimento & desenvolvimento , Microbiologia de Alimentos , Conservação de Alimentos/instrumentação , Luz , Pós/química , Salmonella/crescimento & desenvolvimento , Salmonella/efeitos da radiação
9.
Int J Food Microbiol ; 331: 108786, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32659617

RESUMO

Sweet orange essential oil is obtained from the peels of Citrus sinensis (CSEO) by cold pressing, and used as a valuable product by the food industry. Nanoencapsulation is known as a valid strategy to improve chemical stability, organoleptic properties, and delivery of EO-based products. In the present study we encapsulated CSEO using chitosan nanoemulsions (cn) as nanocarrier, and evaluated its antimicrobial activity in combination with mild heat, as well as its sensorial acceptability in orange and apple juices. CSEO composition was analyzed by GC-MS, and 19 components were identified, with limonene as the predominant constituent (95.1%). cn-CSEO was prepared under low shear conditions and characterized according to droplet size (<60 nm) and polydispersity index (<0.260 nm). Nanoemulsions were stable for at least 3 months at 4 ± 2 °C. cn-CSEO were compared with suspensions of CSEO (s-CSEO) (0.2 µL of CSEO/mL) in terms of antibacterial activity in combination with mild heat (52 °C) against Escherichia coli O157:H7 Sakai. cn-CSEO displayed a greater bactericidal activity than s-CSEO at pH 7.0 and pH 4.0. The validation in fruit juices showed an improved bactericidal effect of cn-CSEO in comparison with s-CSEO when combined with mild heat in apple juice, but not in orange juice. In both juices, the combination of CSEO and mild heat exerted synergistic lethal effects, reducing the treatment time to cause the inactivation of up to 5 Log10 cycles of E. coli O157:H7 Sakai cells. Finally, the sensory characteristics of both juices were acceptable either when using s-CSEO or CSEO nanoemulsified with chitosan. Therefore, as a promising carrier for lipophilic substances, the encapsulation of EOs with chitosan nanoemulsions might represent an advantageous alternative when combined with mild heat to preserve fruit juices.


Assuntos
Quitosana/química , Emulsões/farmacologia , Conservação de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Óleos Vegetais/química , Óleos Vegetais/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Bebidas/microbiologia , Quitosana/farmacologia , Citrus sinensis/química , Contagem de Colônia Microbiana , Emulsões/química , Escherichia coli O157/efeitos dos fármacos , Frutas/química , Temperatura Alta , Malus/microbiologia
10.
Food Chem ; 333: 127502, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32683257

RESUMO

The aim of this study was to evaluate the effectiveness of the use of ethanol, ultrasound and/or vacuum as a pretreatment to melon drying. Eight types of pretreatments were performed in which samples were immersed in ethanol solutions with different concentrations (50% and 100%) using four treatment conditions: immersion, immersion with ultrasound (US), with vacuum (VC) and with ultrasound and vacuum (USVC). Drying was performed at 60 °C and five different semi-theoretical drying mathematical models were examined to characterize the drying curves, and quality analyses were carried out. The condition that obtained the lower drying time was using the US pretreatment in 100% ethanol solution. Drying caused a diminution of bioactive compounds and influenced color parameters. However, the samples immersed in 50% ethanol solution and dried obtained minor losses of total phenolics, total carotenoids, and ascorbic acid contents.


Assuntos
Cucurbitaceae/química , Etanol/farmacologia , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Ácido Ascórbico/análise , Carotenoides/química , Cor , Cucurbitaceae/efeitos dos fármacos , Dessecação , Conservação de Alimentos/instrumentação , Frutas/química , Frutas/efeitos dos fármacos , Fenóis/química , Vácuo
11.
Food Chem ; 333: 127500, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32693317

RESUMO

The objectives of this study were to optimize the condition of ultrasonic treatment combined with aqueous chlorine dioxide (ClO2) on nitrate content of spinach by response surface methodology (RSM), and determine the effectiveness of ultrasound (US) and ClO2 alone and in combination, on spinach postharvest quality during 7 days' storage period. The optimal treatment parameters obtained were ultrasonic power (300 W), ClO2 concentration (50 ppm), treatment time (4 min). The combined treatments significantly reduced the nitrate content and maintained better storage quality in terms of total soluble solids (TSS) and ascorbic acid content compared with the individual treatment or untreated. For Chlorophyll content, the combined treatment was significantly higher than the control and ClO2 treatment, but lower than ultrasonic treatment. The results demonstrated that US combined with ClO2 are promising alternatives for the reduction of nitrate content, as well as preserving the quality of stored leafy vegetables.


Assuntos
Compostos Clorados/farmacologia , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Nitratos/análise , Óxidos/farmacologia , Spinacia oleracea/química , Ultrassom/métodos , Ácido Ascórbico/análise , Clorofila/análise , Conservação de Alimentos/instrumentação , Armazenamento de Alimentos , Folhas de Planta/química , Spinacia oleracea/efeitos dos fármacos , Verduras/química , Verduras/efeitos dos fármacos
12.
Int J Food Microbiol ; 332: 108769, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-32622249

RESUMO

Controlling spoilage of the popular ethnic marinated beef "Shawarma" is crucial to achieve high quality, extend shelf-life, reduce food waste and meet the need of the globalized supply chain. Active essential oil (EO) components (thymol and carvacrol) were added at 0.4% and 0.8% (w/w) to preserve marinated beef, stored under aerobic or vacuum packaging. Microbiological and sensory (odor) parameters were assessed during 21 days at 4 °C. The treatments with higher EO concentration achieved higher antimicrobial activity than the lower ones and significantly reduced the mesophilic total viable count (TVC), lactic acid bacteria (LAB), Brochothrix thermosphacta, Pseudomonas spp., total coliforms, Escherichia coli, yeasts and molds. The higher EO concentration extended the microbiological shelf-life by 6 days, as judged by TVC and compared to the controls (aerobic and vacuum packaging) but was unacceptable sensorially. The lower EO concentration increased the microbiological shelf-life by 3 days and the sensorial shelf-life by 9 and > 12 days, under aerobic and vacuum conditions, respectively.


Assuntos
Cimenos/farmacologia , Conservação de Alimentos/métodos , Produtos da Carne/microbiologia , Timol/farmacologia , Ácido Acético/farmacologia , Animais , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Bovinos , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Óleos Voláteis/química , Óleos Voláteis/farmacologia
13.
Int J Food Microbiol ; 332: 108771, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-32650062

RESUMO

In this research, anti-yeast activity of natamycin in apple juice inoculated with both Zygosaccharomyces rouxii and Z. bailii during the storage at different temperatures was investigated. For this purpose, a response surface methodology approach was used to test and optimize effects of some processing variables; storage time (1, 21 and 41 days), storage temperature (4, 12 and 20 °C), sodium benzoate as a positive control (0, 0.05 and 0.1%) and natamycin concentration (0, 30 and 60 mg/L) on several physicochemical and bioactive properties of the apple juice samples. The results showed that the natamycin performed a remarkable anti-yeast effect on Z. bailii rather than on Z. rouxii. The brix levels of the samples decreased and so the turbidity values increased significantly due to the yeast activity during the storage. Bioactive properties were also significantly affected by the natamycin which was also revealed to increase the antioxidant capacity of apple juice during storage. Using multiple response optimization technique, it was calculated that minimum yeast count (YC) values would occur at storage time = 38.64 and 40.9 days, storage temperature = 19.81 and 14.4 °C, sodium benzoate level (fixed to 0%) and natamycin concentration = 40 and 51.9 mg/L for the samples inoculated with Z. bailii and Z. rouxii, respectively. It was concluded that the bioactive properties of apple juice could be preserved by addition of natamycin which is suggested to be a natural inhibitor during the storage.


Assuntos
Antifúngicos/farmacologia , Conservação de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Natamicina/farmacologia , Zygosaccharomyces/efeitos dos fármacos , Microbiologia de Alimentos , Malus/microbiologia , Temperatura , Fatores de Tempo , Zygosaccharomyces/crescimento & desenvolvimento
14.
PLoS One ; 15(6): e0235472, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32603372

RESUMO

Refrigerated ready-to-eat (RTE) dips often have pH and water activity combinations conducive to the proliferation of foodborne pathogens, including Listeria monocytogenes. This study conducted product assessments of five refrigerated RTE dips: baba ghanoush, guacamole, hummus, pesto, and tahini, along with individual dip components including avocado, basil, chickpeas, cilantro, eggplant, garlic, and jalapeno pepper. Dips and dip components were inoculated with 2 log CFU/g of L. monocytogenes and stored at 10°C for 28 days. The pathogen was enumerated throughout storage and growth rates were determined using the DMFit program to compute the time required for L. monocytogenes to achieve a 1 log CFU/g increase in population. Survival and growth rates varied significantly between the refrigerated RTE dips and dip components assessed in this study. For dips, L. monocytogenes progressively decreased in baba ghanoush, pesto, and tahini. In contrast, the pathogen proliferated in both hummus and guacamole and the highest growth rate was observed in guacamole (0.34±0.05 log CFU/g per day) resulting in a 1 log CFU/g increase in population in 7.8 days. L. monocytogenes proliferated in all dip components with the exception of eggplant and garlic. The pathogen achieved the highest growth rate in chickpeas (2.22±1.75 log CFU/g per day) resulting in a computed 1 log CFU/g increase in only 0.5 days. Results from this study can aid in understanding how L. monocytogenes behaves in refrigerated RTE dips and dip components and data can be utilized in understanding product formulations and in risk assessments.


Assuntos
Fast Foods/microbiologia , Listeria monocytogenes/crescimento & desenvolvimento , Cicer/microbiologia , Qualidade de Produtos para o Consumidor , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Conservação de Alimentos/métodos
15.
Artigo em Inglês | MEDLINE | ID: mdl-32664624

RESUMO

In recent years, the chaotic habits of modern life have favored the consumption of quickly prepared meals, using ready-to-eat (RTE) foods and condiments. The aim of this study was to establish the microbiological safety of RTE sauces and pesto from markets analyzed at different stages of shelf life. In the bacterial investigation, all samples were shown to be acceptable, although differences were observed concerning shelf life times. On the other hand, the fungal investigation showed frequent positive results, with concentrations higher than threshold values. Detected microbial diffusion was the lowest when products were far from the expiry date and had just been opened, while high microbial proliferation was observed when analyzing the same package after 48 h, higher than for a product close to the end of its shelf life. This study highlights the discreet microbiological quality of processed and RTE foods, underlining the importance of hygienic-sanitary surveillance of these foods to their shelf life. Consequently, it is necessary to: (1) implement a food control plan for all food categories to carry out risk analysis associated with their consumption; and (2) better adapt the regulations relating to microbiological analysis, and understand the biological significance of each microbial parameter throughout the shelf life of foods.


Assuntos
Qualidade de Produtos para o Consumidor , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Higiene , Contagem de Colônia Microbiana , Humanos , Listeria monocytogenes , Controle de Qualidade , Inquéritos e Questionários
16.
Int J Food Microbiol ; 330: 108696, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-32502760

RESUMO

Synthetic preservatives can have harmful effects on the body, so plant essential oils appear to be an attractive natural alternative. However, the use of essential oils is limited due to the low stability and possible negative effects on the sensory properties of food. Oil encapsulation was suggested as a way to overcome these drawbacks. The objective of this study was to encapsulate thyme essential oil and to evaluate its antioxidant and antimicrobial potential in vitro and in situ in of hamburger-like meat products. The casein-maltodextrin capsules produced by spray-drying were assessed for encapsulation efficiency, thermal stability, chemical compounds and morphology. Antioxidant activity was evaluated by DPPH, hydroxyl and nitric oxide methods, while antimicrobial activity was evaluated in vitro against four bacteria and in situ in hamburger-like products. The capsule showed high encapsulation efficiency and thermal stability, and spherical and irregular morphology. The casein-maltodextrin encapsulated essential oil showed antioxidant and antimicrobial activity against Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Salmonella Typhimurium tested in vitro and against thermotolerants coliforms and Escherichia coli in situ, showing potential for application as a natural preservative in food.


Assuntos
Antibacterianos/farmacologia , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Produtos da Carne/microbiologia , Óleos Voláteis/farmacologia , Thymus (Planta)/química , Antibacterianos/química , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Dessecação , Microbiologia de Alimentos , Conservantes de Alimentos/química , Temperatura Alta , Óleos Voláteis/química
17.
Int J Food Microbiol ; 330: 108713, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-32512363

RESUMO

Sodium metabisulfite (SMBS), potassium metabisulfite (PMBS), aluminum sulfate (AlS) and aluminum potassium sulfate (AlPS), common sulfur-containing salts used as food additives, were evaluated for their antifungal activity against Penicillium digitatum, Penicillium italicum and Geotrichum citri-aurantii, the most economically important pathogens causing postharvest diseases of citrus fruits. In vitro radial mycelial growth was measured on potato dextrose agar (PDA) Petri dishes amended with five different concentrations of the salts (10, 20, 30, 50, 100 mM) after 7 d of incubation at 25 °C. SMBS and PMBS at all concentrations, and AIS and AIPS above 20 mM, completely inhibited the growth of these fungi. The curative antifungal activity of the four salts to control citrus green (GM) and blue (BM) molds and sour rot (SR) was evaluated on 'Valencia' oranges artificially inoculated in rind wounds with P. digitatum, P. italicum and G. citri-aurantii, respectively. In vivo primary screenings showed no significant antifungal activity of AlS and AlPS to control the three diseases at any dose tested, but SMBS and PMBS reduced the incidence and severity of GM, BM and SR at various concentrations. Effective salts and concentrations were selected for in vivo dip treatments in small-scale trials. Dips at room temperature (20 °C) in SMBS and PMBS at 20 and 50 mM for 60 or 120 s significantly reduced the incidence and severity of GM and BM, with PMBS at 50 mM for 120 s the most effective treatment. Conversely, dips in SMBS and PMBS at 50 mM for 60 or 120 s did not reduce SR incidence and severity. SMBS and PMBS treatments are potentially new tools to be included in reduced-risk non-polluting strategies to control Penicillium diseases, but not SR, on citrus fruits.


Assuntos
Antifúngicos/farmacologia , Citrus/microbiologia , Aditivos Alimentares/farmacologia , Doenças das Plantas/prevenção & controle , Enxofre/farmacologia , Aditivos Alimentares/química , Conservação de Alimentos/métodos , Frutas/microbiologia , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Temperatura , Fatores de Tempo
18.
Food Chem ; 329: 126989, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32502742

RESUMO

In this study, a polyethylene (PE) film coated with chitosan (CS) and gallic acid (GA) was prepared using plasma modification technology and applied for the preservation of tilapia fillets. Based on the analysis of surface morphology and surface functional groups, it was shown that plasma modification allowed CS and GA coating on PE. And GACS/PE demonstrated better antioxidant ability than CS/PE and GA/PE individually. The results of the tilapia freshness test showed that the total plate count showed that GACS/PE can inhibit 1.52 log CFU/g and delay the production of volatile basic nitrogen below 15 mg/100 g after 14 d of storage. Moreover, GA/PE (0.26 mg MDA/kg) and GACS/PE (0.24 mg MDA/kg) showed better thiobarbituric acid inhibitiry effect than control (0.30 mg MDA/kg) on day 14. These results indicate that these packaging films are efficient in extending the shelf life of tilapia fillets.


Assuntos
Quitosana/química , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Ácido Gálico/química , Polietileno/química , Tilápia , Animais
19.
Food Chem ; 329: 127213, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32516713

RESUMO

Chitosan and whey protein isolate (WPI) conjugate films were prepared as a novel matrix for encapsulating and extending the postharvest shelf life of strawberries. Film forming solutions of chitosan, WPI, and chitosan-WPI conjugate were mixed with glycerol, casted for films at 60 ± 2 °C and assessed for their colour, water vapour and oxygen transfer rate, textural, functional groups and secondary structure, thermal, crystallinity, and antioxidant properties. Chitosan-WPI conjugate films were applied as an edible coating on strawberries, and studied for storage stability at 5 °C and 20 °C by assessing physical and biochemical parameters. A considerable reduction in colour indices, weight loss, pH and titratable acidity, reducing sugars, ascorbic acid, total phenolics, DPPH and ABTS assay was noted in the coated strawberries over the control at both the studied temperatures. The control strawberries had a shelf life of 5 and 3 days, whereas coating enhanced the shelf life of strawberries to 8 and 5 days when stored at 5 °C and 20 °C, respectively.


Assuntos
Quitosana/química , Conservação de Alimentos/métodos , Proteínas do Soro do Leite/química , Antioxidantes/química , Ácido Ascórbico/análise , Varredura Diferencial de Calorimetria , Cor , Fragaria/química , Fragaria/metabolismo , Frutas/química , Frutas/metabolismo , Glicerol/química , Concentração de Íons de Hidrogênio , Fenóis/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
20.
Food Chem ; 330: 127268, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32540519

RESUMO

Essential oils (EOs) are natural, volatile and aromatic liquids extracted from special plants. EOs are complex mixture of secondary metabolites (terpenes, phenolic compounds, alcohol). EOs possess a wide range of biological activities including antioxidant, antimicrobial and anti-inflammatory ones. Particularly, EOs exhibit pronounced antibacterial and food preservative properties that represent a real potential for the food industry. Numerous EOs have the potential to be used as a food preservative for meat and meat products, vegetables and fruits as well as for dairy products. The main obstacles for using EOs as food preservatives are their safety limits, marked organoleptic effects and possible contamination by chemical products such as pesticides. This review aims to provide an overview of current knowledge about EOs food preservative properties with special emphasis on their antibacterial activities and to support their uses as natural, eco-friendly, safe and easily biodegradable agents for food preservation.


Assuntos
Conservação de Alimentos/métodos , Conservantes de Alimentos/química , Conservantes de Alimentos/farmacologia , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Inocuidade dos Alimentos , Frutas/química , Humanos , Carne , Produtos da Carne , Metabolismo Secundário , Terpenos/análise , Verduras
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