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1.
Heliyon ; 10(6): e27442, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38500975

RESUMO

The objective of this study was to identify the requirements needed for selling dairy products through e-commerce, as well as current gaps and challenges that exist for small scale dairy processors (SSDPs), and need to be addressed in order to comply with those requirements. A mixed method research design was used for training needs assessment. Qualitative (in-depth interview with 7 online platform representatives (OPRs)) and quantitative approach (survey questionnaire with 58 SSDPs) were conducted. Interview transcripts were coded and codes were grouped into seven themes. Hierarchical cluster analysis was applied to 146 answers from 58 SSDPs. They were divided into 4 clusters. Mean sums of responses between clusters were compared by Mann-Whitney U test. OPRs suggested that SSDPs should be provided with tools and resources to help them achieve food safety and quality targets, as well as practical knowledge and skills. They reported that it is crucial to find a solution for the cold chain transportation, for maintaining consistent product quality. Survey results showed that SSDPs use kitchen equipment (79.3%) and kitchen cleaning products (81.0%) for dairy processing. In total, 43.1% process raw milk and only 24.1% have product label on the package. Only members of cluster 3 and 4 sell their products online (73.7% and 90.0%, respectively), mostly using their own social media platforms (57.9% and 60.0%, respectively), transporting products to end buyers by themselves in hand refrigerators (47.4% and 70.0%, respectively). By analyzing the differences among clusters of SSDPs, trainings can be tailored to the characteristics and knowledge gaps of each group.

2.
Food Chem Toxicol ; 186: 114541, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38395188

RESUMO

In contrast to the traditional approach to risk assessment, which focuses on a single chemical, cumulative exposure and risk assessment considers the consequences of exposure to multiple chemical combinations. A cumulative risk assessment of dietary exposure of adult females and adult males to pesticides with chronic effects on the thyroid was conducted by estimation of the Total Margin of Exposure (MOET). Exposure to each active substance was estimated using a second-order Monte Carlo simulation. Input values for the simulation were based on over 2300 conventionally produced fruit and vegetable samples analysed from 2021 to 2023 and consumption data collected using the Food Frequency Questionnaire (FFQ) and 24h recall method. MOET values, for both populations assessed, did not exceed thresholds for regulatory consideration established by risk managers. Considering that MOETs values from consumption of fresh fruits and vegetables were relatively close to the threshold value, total exposure to the pesticides could likely reach risk-associated MOET levels, through the consumption of other food products that may be contaminated.


Assuntos
Resíduos de Praguicidas , Praguicidas , Praguicidas/toxicidade , Praguicidas/análise , Verduras/química , Frutas/química , Exposição Dietética/análise , Glândula Tireoide , Sérvia , Medição de Risco , Resíduos de Praguicidas/análise , Contaminação de Alimentos/análise
3.
J Sci Food Agric ; 2024 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-38308592

RESUMO

BACKGROUND: Titanium dioxide (TiO2 ) is banned in some countries but its use is still permitted in others. The global food supply chain is therefore challenged with the need to use rapid and reliable testing methods to either detect the presence of TiO2 or to quantify its concentration. The goal of this study was to determine the feasibility of using color, texture profile analysis, Raman microscopy, and X-ray fluorescence (XRF) spectroscopy to detect and quantify TiO2 in fillings used in the pastry and confectionery industry. In this study, two types of fillings were investigated: vanilla based and chocolate based. All fillings were prepared in four different variations - without TiO2 and with three concentrations as follows: 0.25 g*kg-1 , 0.5 g*kg-1 , or 0.75 g*kg-1 TiO2 per sample. The methods were selected for their ability to analyze the samples in a short period of time. RESULTS: All of the methods showed moderate to high potential for detecting TiO2 in the samples. The results reveal how TiO2 affects the food matrix color and texture. Use of Raman microscopy confirms its detectability, although concentrations of TiO2 do not follow a pattern. X-ray fluorescence spectroscopy showed the greatest potential as it can not only detect TiO2 but can also quantify its concentration in the samples. CONCLUSIONS: The highest potential for quantifying the concentration of this food additive was achieved with XRF. © 2024 Society of Chemical Industry.

4.
J Verbrauch Lebensm ; 18(2): 133-146, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37265593

RESUMO

Understanding consumers' behavior and their handling of high-risk foods at home is essential for reducing the number of foodborne illnesses. This study shows the results of a cross-national analysis of consumers' perception from nine countries, and the identification of customers' clusters and its characteristics in order to understand customers' behavior, and to build safe chilled ready-to-eat (RTE) foods prevention strategies. The cluster analysis resulted in two clusters: (1) "Precautious consumers" characterized by the orientation towards pre-packed RTE foods, with consumers mainly coming from Bosnia and Herzegovina, India, Poland, Portugal, Spain, and Turkey. Their attitudes and self-reported practices may be categorized as less risky in terms of food-borne illnesses connected with the consumption of RTE foods; (2) "Unconcerned consumers" preferred cutting and slicing RTE foods freshly at the point of purchase, usually sold at the delicatessen department in a supermarket or at open markets. Those consumers mostly came from Croatia, Serbia and Slovenia and their attitudes and self-reported practices were riskier. These results allow a better understating of what characterizes consumers of RTE foods in different countries.

5.
Food Chem Toxicol ; 178: 113906, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37343714

RESUMO

Considering the genotoxic and cancerogenic nature of aflatoxin M1 (AFM1), its presence in milk and dairy products may pose health risks for consumers. The chronic exposure was calculated using a two-dimensional (second order) Monte Carlo model. Results of 13 722 milk and dairy product samples analysed in the 2015-2022 period were used. Milk and dairy products intake information was collected with a Food Frequency Questionnaire (FFQ) validated by a 24-h recall-based method. Risk characterization was done by calculation of the Margin of Exposure (MOE) and by calculation of AFM1 induced number of hepatocellular carcinoma (HCC) cases. Mean AFM1 Estimated Daily Intake (EDI) was highest in children at 0.336 (CI: 0.294-0.385) ng kg-1 bw day-1, followed by adolescents with 0.183 (CI: 0.164-0.204), then adult females with 0.161 (CI: 0.146-0.179) and finally adult males with lowest EDI of 0.126 (CI: 0.115-0.139) ng kg-1 bw day-1. MOE values based on mean EDI for all population groups were above risk associated threshold and the number of possible HCC cases was in the range of 0.0002-0.0021 cases per year for 105 individuals. The results suggest low health risks due to AFM1 exposure for the whole population. Still, this risk is not non-existent, especially for children as they have a higher ratio of the population exposed to risk associated AFM1 levels, with MOE values below risk indicating threshold starting at 77.5th percentile.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Adulto , Masculino , Criança , Feminino , Adolescente , Humanos , Animais , Aflatoxina M1/toxicidade , Aflatoxina M1/análise , Exposição Dietética/análise , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/epidemiologia , Sérvia/epidemiologia , Contaminação de Alimentos/análise , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/epidemiologia , Leite/química
6.
Foods ; 13(1)2023 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-38201081

RESUMO

The main objective of this study was to investigate how food fraud is perceived among consumers in Serbia and Montenegro. A total of 1264 consumers from the two countries participated in an online survey during the second half of 2022, using Google forms®. In the Serbian population, older or highly educated respondents are aware of different types of fraudulent activities such as substitution, mislabeling, concealment, and counterfeiting. Dilution is mostly recognized by women, the younger population, and students. Consumers believe that trust is the most important factor when purchasing food. The highest level of agreement regarding food fraud is that such activities may pose serious health risks to consumers, and that food inspection services are the most responsible actors in the food chain continuum. When it comes to purchasing food, open green markets are most trustworthy, followed by hypermarkets. Concerning the types of food, fish is most susceptible to fraud, followed by olive oil. This study builds upon existing knowledge of food consumers about food fraud in Europe.

7.
Foods ; 9(9)2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32878141

RESUMO

The aim of this study was to compare the sensory quality and acceptance of dried ready-to-eat beetroot snacks as a result of different drying methods applied: supercritical CO2-drying (scCO2-drying), frying, and freeze-drying. Descriptive sensory analysis, quality rating (10 assessors), and consumer acceptance testing (n = 102) were performed. Mean overall quality scores within the range of "very good" quality were found only in non-precooked scCO2-dried samples which were characterized by typical magenta color, low level of shape and surface deformations, pronounced brittleness and crispiness, and good rehydration during mastication. The other samples were in the range of "good" quality. The pre-cooking step before scCO2-drying negatively influenced the sensory quality parameters, particularly appearance. Around 60% of tested consumers showed a preference for the fried and non-precooked scCO2-dried samples. The drivers of liking were mostly related to the characteristics of the product, which was salted, fried, and crispy, with an oily and overburnt flavor, i.e., the product most similar to commercial potato chips products. Freeze-drying had a negative effect primarily on appearance and flavor. According to the sensory evaluation conducted, direct scCO2-drying without a pre-cooking step showed itself as a promising alternative drying technology in the production of dried beetroot snacks.

8.
FEMS Microbiol Lett ; 367(10)2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32436572

RESUMO

Fresh fruits are a potential source of many different pathogens, including bacteria, enteric viruses and protozoa that may pose serious health risks. The consumption of raspberries has been widely associated with large foodborne outbreaks and because of the low concentration at which most of these pathogens are found, sensitive and accurate detection methods are required. Methods that would allow for an accurate and sensitive simultaneous elution and concentration of the different classes of pathogens would decrease the time for analysis, the costs associated and the expertise necessary. In this study we explored the use of polyethylene glycol (PEG) secondary concentration to simultaneously concentrate bacteria, enteric viruses and protozoa from raspberries. PEG secondary concentration showed good recovery rates for all the organisms tested. This work indicates that PEG secondary concentration followed by quantitative (Reverse Transcription) Polymerase Chain Reaction (q(RT)PCR) may be a relevant alternative to standardized methods for the simultaneous concentration of bacteria, enteric viruses and protozoa.


Assuntos
Bactérias/genética , Eucariotos/genética , Microbiologia de Alimentos/métodos , Parasitologia de Alimentos/métodos , Polietilenoglicóis , Vírus/genética , Bactérias/classificação , Bactérias/isolamento & purificação , Eucariotos/classificação , Eucariotos/isolamento & purificação , Polietilenoglicóis/química , Reação em Cadeia da Polimerase , Vírus/classificação , Vírus/isolamento & purificação
9.
Sci Total Environ ; 698: 134185, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505354

RESUMO

Drinking water quality has been regulated in most European countries for nearly two decades by the drinking water directive 98/83/EC. The directive is now under revision with the goal of meeting stricter demands for safe water for all citizens, as safe water has been recognized as a human right by the United Nations. An important change to the directive is the implementation of a risk-based approach in all regulated water supplies. The European Union Framework Seventh Programme Aquavalens project has developed several new detection technologies for pathogens and indicators and tested them in water supplies in seven European countries. One of the tasks of the project was to evaluate the impact of these new techniques on water safety and on water safety management. Data were collected on risk factors to water safety for five large supplies in Denmark, Germany, Spain and the UK, and for fifteen small water supplies in Scotland, Portugal and Serbia, via a questionnaire aiming to ascertain risk factors and the stage of implementation of Water Safety Plans, and via site-specific surveys known as Sanitary Site Inspection. Samples were collected from the water supplies from all stages of water production to delivery. Pathogens were detected in around 23% of the 470 samples tested. Fecal contamination was high in raw water and even in treated water at the small supplies. Old infrastructure was considered a challenge at all the water supplies. The results showed that some of the technique, if implemented as part of the water safety management, can detect rapidly the most common waterborne pathogens and fecal pollution indicators and therefore have a great early warning potential; can improve water safety for the consumer; can validate whether mitigation methods are working as intended; and can confirm the quality of the water at source and at the tap.


Assuntos
Água Potável/química , Monitoramento Ambiental , Purificação da Água , Abastecimento de Água , Microbiologia da Água , Qualidade da Água
10.
J Microbiol Methods ; 168: 105786, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31770538

RESUMO

There is increasing interest in methodologies for the simultaneous concentration and detection of multiple targets in individual samples. The aim of this study was to investigate the potential presence of E. coli DNA in beef extract powder used as part of a procedure to concentrate water samples for the simultaneous detection of bacteria, viruses and protozoa. DNA from E. coli was detected in five out of six beef extract lots tested, demonstrating the limitations of its inclusion when being used in assays that will be used for the detection of E. coli in water samples. Further work is required to clarify if this phenomenon also occurs for other microorganisms of interest in water.


Assuntos
DNA Bacteriano/isolamento & purificação , Escherichia coli O157/genética , Reação em Cadeia da Polimerase em Tempo Real , Carne Vermelha , Microbiologia da Água , Animais , Bovinos , Contagem de Colônia Microbiana , DNA Bacteriano/genética , Manejo de Espécimes/métodos
11.
Int J Food Microbiol ; 167(2): 236-43, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24129156

RESUMO

The potential of Bacillus cereus to cause a diarrheal toxico-infection is related to its ability to perform de novo enterotoxin production in the small intestine. A prerequisite for this is presence of sufficient numbers of B. cereus that have survived gastro-intestinal passage. It is known that the percentage of survival is much smaller for vegetative cells in comparison to spores and it is therefore important to know the state in which B. cereus is ingested. The results of the current study performed on twelve B. cereus strains, comprising both diarrheal and emetic type, indicate that exposure via contaminated foods mainly concerns vegetative cells. Inoculated vegetative cells grew to high counts, with the growth dynamic depending on the storage temperature. At 28 °C growth to high counts resulted in spore formation, in general, after 1 day of storage. One strain was an exception, producing spores only after 16 days. At 12 °C obtained high counts did not result in spore formation for 11 of 12 tested strains after two weeks of storage. The highest counts and time to sporulation were different between strains, but no difference was observed on the group level of diarrheal and emetic strains. The spore counts were always lower than vegetative cell counts and occurred only when food was obviously sensory spoiled (visual and odor evaluation). Similar observations were made with food inoculated with B. cereus spores instead of vegetative cells. Although the prospect of consuming spores was found very weak, the numbers of vegetative B. cereus cells were high enough, without obvious sensory deviation, to survive in sufficient level to cause diarrheal toxico-infection.


Assuntos
Bacillus cereus/crescimento & desenvolvimento , Fast Foods/microbiologia , Contaminação de Alimentos/análise , Esporos Bacterianos/isolamento & purificação , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Enterotoxinas/isolamento & purificação , Microbiologia de Alimentos , Armazenamento de Alimentos , Temperatura
12.
Food Microbiol ; 28(5): 869-72, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21569928

RESUMO

Previous study showed that repetitive mild decontamination treatments with intense light pulses (ILP) and lactic acid (LA) can induce increased resistance in surviving pathogenic cells. Research has evaluated the potential of increased resistance to enhance the persistence of resistant variants of Listeria monocytogenes and Escherichia coli O157:H7 under suboptimal growth conditions. Growth of resistant variants and parental strains was determined by optical density (OD) measurements in nutrient broths with different pH values and NaCl concentration, at low temperature. The real lag phase was calculated, and results indicated that intense light pulses (ILP) resistant variants needed longer time to initiate growth compared to their parental strains, for both L. monocytogenes and E. coli O157:H7 when incubated at 7 °C and 10 °C, respectively. These selected variants were of the similar resistance towards heat and low pH (no cross-tolerance). Nevertheless, lactic acid (LA) resistant variant of L. monocytogenes was cross-protected when exposed to low pH, but not when treated with heat.


Assuntos
Escherichia coli O157/crescimento & desenvolvimento , Conservação de Alimentos/métodos , Ácido Láctico/farmacologia , Listeria monocytogenes/crescimento & desenvolvimento , Escherichia coli O157/efeitos dos fármacos , Escherichia coli O157/efeitos da radiação , Microbiologia de Alimentos , Temperatura Alta , Concentração de Íons de Hidrogênio , Luz , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/efeitos da radiação , Viabilidade Microbiana/efeitos dos fármacos , Viabilidade Microbiana/efeitos da radiação
13.
Foodborne Pathog Dis ; 8(2): 325-8, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21034266

RESUMO

The aim of this study was to investigate the response of Campylobacter jejuni at single-cell level when exposed to different concentrations of chlorine dioxide (ClO(2)). The parameter of choice, intracellular pH (pH(i)), was determined by using fluorescence ratio imaging microscopy with a pH-sensitive, ratiometric 5(6)-carboxyfluorescein diacetate succinimidyl ester probe. In addition, the culturability expressed in colony counts was determined. Our results revealed that several subpopulations with different physiological states, as judged by their pH(i), were created by ClO(2) treatment. The greater the concentration of ClO(2), the smaller the subpopulation of healthy cells with pH(i) > 6.8 and the smaller the colony count as determined on nonselective agar plates. ClO(2) at concentrations (60 ppm) induced injuries that resulted in complete loss of culturability and adversely affected the ability to resuscitate under subsequent more favorable conditions. The presence of injured cells in food could present a risk for public health. Additional hurdles have to be included in food preservation to suppress the survival and recovery of injured cells.


Assuntos
Campylobacter jejuni/efeitos dos fármacos , Campylobacter jejuni/metabolismo , Compostos Clorados/farmacologia , Desinfetantes/farmacologia , Óxidos/farmacologia , Campylobacter jejuni/crescimento & desenvolvimento , Compostos Clorados/administração & dosagem , Contagem de Colônia Microbiana , Desinfetantes/administração & dosagem , Relação Dose-Resposta a Droga , Corantes Fluorescentes/química , Conservação de Alimentos/métodos , Concentração de Íons de Hidrogênio , Viabilidade Microbiana , Microscopia de Fluorescência , Óxidos/administração & dosagem , Análise de Célula Única , Especificidade da Espécie
14.
Int J Food Microbiol ; 140(2-3): 201-6, 2010 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-20434228

RESUMO

Quantitative risk assessment studies performed elsewhere showed the importance of reducing counts of Campylobacter jejuni on chicken carcasses for decrease of incidence of human campylobacteriosis. The current study indicated that 1.8 log CFU/g reduction of inoculated C. jejuni (6 log CFU/g) can be achieved by decontamination with lactic acid buffered with sodium lacatate (LA/NaLA, 10% w/v, pH 3.0). Subsequent packaging under modified atmosphere of 80% O(2)/20%N(2) resulted in additional reduction of approximately 1.2 log CFU/g. These results were confirmed in naturally contaminated samples (2-3 log CFU/g) resulting in immediate reduction of present C. jejuni under the limit of enumeration (1 log CFU/g). However, enrichment showed presence of C. jejuni in 10g of sample. Under 80% O(2) LA/NaLA treated C. jejuni remained detectable per 10g until day 7, after which no positive samples were found until the end of the two-weeks storage. Under 80% CO(2) LA/NaLA treated C. jejuni remained fluctuating at 10 CFU/g until the end of two-weeks storage. Control cells were reduced by approx. 1.5 log CFU/g during storage under 80% O(2)/20% N(2), whereas no reduction was observed under 80% CO(2)/20% N(2). The present study showed the potential of buffered lactic acid and high-O(2) MAP to reduce C. jejuni both on inoculated and naturally contaminated samples. The immediate effect of decontamination was further extended by additive, not synergistic, effect of 80% O(2), suggesting the practical value of the tested concept in combating C. jejuni on chicken carcasses.


Assuntos
Campylobacter jejuni/crescimento & desenvolvimento , Descontaminação/métodos , Desinfetantes/farmacologia , Embalagem de Alimentos/métodos , Carne/microbiologia , Viabilidade Microbiana/efeitos dos fármacos , Animais , Campylobacter jejuni/efeitos dos fármacos , Dióxido de Carbono/farmacologia , Galinhas , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Embalagem de Alimentos/instrumentação , Ácido Láctico/farmacologia , Oxigênio/farmacologia , Lactato de Sódio/farmacologia
15.
Int J Food Microbiol ; 141 Suppl 1: S140-6, 2010 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-20149937

RESUMO

As mild decontamination treatments are gaining more and more interest due to increased consumer demands for fresh foods, it is of great importance to establish the influence of decontamination treatments on the subsequent bacterial behaviour under suboptimal storage conditions. For this purpose Campylobacter jejuni cells treated with lactic acid (LA, 3% lactic acid, pH 4.0, 2 min) or chlorine dioxide (ClO(2), 20 ppm, 2 min) were inoculated in Bolton broth (pH 6.0) and incubated under 80% O(2)/20% N(2), 80% CO(2)/20% N(2), air or micro-aerophilic (10% CO(2)/85% N(2)/5% O(2)) atmosphere, at 4 degrees C during 7 days. Treatment with water served as a control. The most suppressive atmosphere for the survival of C. jejuni was O(2)-rich atmosphere, followed by air, micro-aerophilic and CO(2)-rich atmosphere. The survival of C. jejuni was dependent on the type of initial decontamination treatment, with water treated cells showing the greatest survival followed by LA and ClO(2) treated cells. Intracellular pH (pH(i)) of individual C. jejuni cells was determined using Fluorescence Ratio Imaging Microscopy (FRIM). At all tested conditions, different subpopulation of the cells could be distinguished based on their pH(i) values. The pH(i) response was independent on the surrounding atmosphere since similar distribution of the subpopulations was observed for all tested atmospheres. However, the pH(i) response was dependent on the initial decontamination treatment. The investigation of intracellular parameters gave an insight into pathogen behaviour under stressful conditions at intracellular level. The results obtained in this study highlighted the importance of combining decontamination technologies with subsequent preservation techniques to the control survival and growth of foodborne pathogens.


Assuntos
Campylobacter jejuni/efeitos dos fármacos , Compostos Clorados/farmacologia , Descontaminação/métodos , Conservação de Alimentos/métodos , Ácido Láctico/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Óxidos/farmacologia , Estresse Fisiológico , Ar , Campylobacter jejuni/fisiologia , Dióxido de Carbono/fisiologia , Manipulação de Alimentos , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Microscopia de Fluorescência , Oxigênio/fisiologia , Temperatura , Água
16.
Int J Food Microbiol ; 141 Suppl 1: S29-42, 2010 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-20056287

RESUMO

The objective of this review has been to disclose collected information on benefits and risks of selected "less-than - sterilizing" processes applied to control microbial hazards in food that was meticulously collected and critically reviewed during five years of EU Sixth framework project "Pathogen Combat". The target organisms of the project, and thus of this review, too, were Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter jejuni. Due to their specific response and high relevancy to the food safety, foodborne viruses and spores, were also discussed within the scope of this review. Selected treatments comprised High Pressure Processing, Intense Light Pulses, treatments with organic acids, treatments with chlorine dioxide and for their relevancy also mild heat treatments and Pulsed Electric Field processing were included. The main aspects included in this review were principles of the processes used and their application, sub-lethal injury and its consequences on microbial food safety, and legal platform and its impact on wide use of the treatments. Finally a reflection has been made to combined application of different hurdles and accompanying risks.


Assuntos
Bactérias , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Inocuidade dos Alimentos/métodos , Esterilização/métodos , Humanos
17.
Food Microbiol ; 26(8): 889-95, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19835777

RESUMO

While maintaining nutritional and sensorial attributes of fresh foods mild processing technologies generally deliver microbiologically perishable food products. Currently little information exists on possible increase in the resistance of pathogens after repetitive exposure to mild (sub-lethal) treatments. Multiple strain-cocktails of Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter jejuni were exposed to 20 consecutive cycles of sub-lethal inactivation by three different techniques. Used techniques comprised inactivation with lactic acid (LA), chlorine dioxide (ClO(2)) and intense light pulses (ILP). Results showed that the selection of resistant cells was both species and technique dependent. While repetitive cycles of ClO(2) treatment did not result in increased resistance, repetitive inactivation with LA yielded L. monocytogenes culture of higher resistance in comparison to the parental culture. The increased resistance, expressed as decreased level of reduction in bacterial counts in subsequent inactivation cycles, was also observed with ILP for both L. monocytogenes and E. coli O157:H7 strains. Visual trend observations were confirmed through statistical linear regression analysis. No such effects were noted for C. jejuni which became undetectable after first 2-5 cycles. Current findings indicate the ability of foodborne pathogens to adapt to mild bactericidal treatments creating new challenges in risk assessment and more specifically in hazard analysis.


Assuntos
Adaptação Fisiológica , Campylobacter jejuni/efeitos dos fármacos , Campylobacter jejuni/fisiologia , Desinfetantes/farmacologia , Escherichia coli O157/efeitos dos fármacos , Escherichia coli O157/fisiologia , Listeria monocytogenes/fisiologia , Campylobacter jejuni/efeitos da radiação , Compostos Clorados/farmacologia , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Farmacorresistência Bacteriana , Escherichia coli O157/efeitos da radiação , Irradiação de Alimentos , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Ácido Láctico/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/efeitos da radiação , Óxidos/farmacologia , Especificidade da Espécie
18.
Int J Food Microbiol ; 135(2): 136-43, 2009 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-19720418

RESUMO

The aim of the study was to determine intracellular pH (pH(i)) as an indicator of the physiological state of two Campylobacter jejuni strains (603 and 608) at the single cell level after bactericidal treatment with lactic acid (3% v/v lactic acid, pH 4.0, 0.85% w/v NaCl) and during recovery and survival using Fluorescence Ratio Imaging Microscopy (FRIM). After exposure to lactic acid solution a decline in pH(i) to 5.5 (FRIM detection limit) was observed in the majority of cells (75-100%) within 2 min. The enumeration data revealed that after 2 min of lactic acid exposure, approx. 90% of the initial population became unculturable. In the following 10 min of exposure, a further decrease in the cell count was observed resulting in 3.53 and 3.21 log CFU/ml reduction of culturable cells at the end of the treatment. On the contrary, the FRIM results revealed that the subpopulations with pH(i)>5.5 increased between 2 and 12 min of exposure to lactic acid. Removing the acid stress and incubating the cells suspension under the more favourable conditions resulted in an immediate increase in cell population with pH(i)>pH(ex) for both C. jejuni strains. Further 24 h incubation at 37 degrees C resulted in increased pH(i) and colony count (recovery study). On the contrary, 24 h incubation at suboptimal temperature of 4 degrees C, showed pH(i) decrease to pH(ex)=6.0 (no pH gradient) in the whole population of C. jejuni cells. Rather than dying, cells exposed for longer time (72 and 120 h) to 4 degrees C increased the subpopulation of the cells with positive pH gradient, mostly comprised of the cells with DeltapH>0.5, indicating the ability of C. jejuni cells to regulate their metabolic activity under suboptimal conditions.


Assuntos
Adaptação Fisiológica , Campylobacter jejuni/fisiologia , Descontaminação , Concentração de Íons de Hidrogênio , Ácido Láctico , Viabilidade Microbiana , Campylobacter jejuni/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Microscopia de Fluorescência/métodos , Estresse Fisiológico , Temperatura
19.
Food Microbiol ; 26(6): 629-37, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19527839

RESUMO

The utilization of sub-lethal decontamination treatments gains more and more interest due to the increased consumers' demand for fresh, minimally processed and convenient food products. These products rely on cold chain and hurdle (combination) technology to provide microbiological safety and quality during their shelf life. To investigate the ability of surviving cells to resuscitate and grow in a food simulating environment, sub-lethal decontamination treatments were coupled with subsequent storage under sub-optimal growth conditions. For this purpose chlorine dioxide (ClO2) and neutralized electrolyzed oxidizing water (NEW)-treated cultures of Escherichia coli O157:H7 were inoculated in TSB-YE of pH 5.8 and aw 0.99, and stored at 10 degrees C, 12.5 degrees C and 15 degrees C, under four different atmospheres (0%, 30% and 60% CO2 balanced with N2, and air). Due to the severity of injury, lactic acid-treated cells were inoculated in TSB-YE pH 7.0. Data obtained reveal that the fraction of sub-lethally injured E. coli O157:H7 undergoes an additional inhibitory effect during the storage period under of sub-optimal conditions. Observed extension in the lag growth phase was a direct consequence prior sub-lethal injury. The effects of liquid ClO2 and NEW were less pronounced in comparison to lactic acid. The current study signifies the potential utilization of appropriate combination of different extrinsic and intrinsic factors in the elimination or growth inhibition of food-borne pathogens.


Assuntos
Compostos Clorados/farmacologia , Escherichia coli O157/crescimento & desenvolvimento , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Embalagem de Alimentos/métodos , Ácido Láctico/farmacologia , Óxidos/farmacologia , Dióxido de Carbono/metabolismo , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Escherichia coli O157/efeitos dos fármacos , Conservação de Alimentos/métodos , Concentração de Íons de Hidrogênio , Nitrogênio/metabolismo , Oxigênio/metabolismo , Temperatura , Água/farmacologia
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