ABSTRACT
Cheeses are dairy products that can potentially contain a diverse range of harmful bacteria that could be consumed by humans, including the enteric pathogen Escherichia coli. This study aimed to characterize the presence of total coliforms, assess the antimicrobial susceptibility profiles of the main commercial antimicrobial classes and biocides, and evaluate the ability of 50 E. coli isolates obtained from fresh cheese sold in the southern region of Espírito Santo, Brazil, to produce biofilms. The counts of total coliforms + E. coli obtained averages of (A) 7.22 × 106 CFU/g, (B) 9.35 × 107 CFU/g, and (C) 1.16 × 106 CFU/g for different brands. All isolates were capable of forming biofilms, with 8%, 76%, and 16% of these isolates presenting high, moderate, and low adherence in biofilm formation, respectively. Most strains showed inhibition halos for the biocides chlorhexidine digluconate 2% (16 mm ± 4.34), iodopovidone 10% (7.14 mm ± 0.36), and sodium hypochlorite 2% (7.12 mm ± 0.33). Out of the 50 strains, 21 (42%) were resistant to at least one of the antimicrobials. Regarding the multiple resistance index, 3 (6%) strains were resistant to 3 or more antimicrobial classes. Furthermore, 2 (4%) were extended-spectrum beta-lactamases producers. Resistance to ampicillin and amoxicillin was observed in 20% and 40% of the strains, respectively. In contrast, gentamicin was the most effective antimicrobial, with a sensitivity rate of 100%. The findings indicate that E. coli present in fresh cheese may possess unique physiological characteristics that could be associated with their persistence, virulence, and multidrug resistance. These results raise significant public health concerns since contaminated food can pose risks to consumers' health, emphasizing the importance of reinforcing hygienic-sanitary controls at all stages of production.
Subject(s)
Cheese , Disinfectants , Humans , Animals , Escherichia coli , Anti-Bacterial Agents/pharmacology , Cheese/microbiology , Virulence Factors , Drug Resistance, Bacterial , Milk/microbiology , Disinfectants/pharmacologyABSTRACT
Abstract Background: Goat production has grown worldwide as a way to improve the quality of rural life and reduce the environmental footprint; nevertheless, there is a need to increase productivity through improved feeding strategies. The market demands healthier products with organoleptic characteristics similar to the traditional ones; thus, it is necessary to evaluate the effect of new forages for goats and its acceptance by consumers. Chemical and organoleptic composition of goat milk vary according to the diet which, in turn, affects the characteristics of cheese. Cheese texture, taste and smell are the most important sensory attributes for consumers. Objective: To evaluate the effect of substituting corn straw with sunflower hay associated with chickpea for dairy goats on yield, chemical composition and sensory acceptability of cheese, as well profitability. Methods: Twenty-eight Saanen dairy goats were randomly assigned to two treatments in a 30-day experiment on a small farm. The daily ration per goat in the MZST treatment (control treatment) consisted of alfalfa hay (200 g/goat/day) and concentrate (400 g/goat/day) plus 600 g/goat/day (50% of the ration) of corn straw. The SFCP treatment substituted corn straw with sunflower-chickpea hay; it had the same alfalfa and concentrate content, but with no corn straw and was added with 600 g/goat/day of sunflower-chickpea hay. The yield, composition and sensory evaluation of fresh cheese made with milk from each treatment were recorded, and the feeding costs and returns evaluated. Variables for the chemical composition of cheese were analyzed following a completely randomized design. Results: Significant differences were observed in cheese yield and all chemical composition variables. According to sensory evaluation, SFCP cheese had significantly higher scores for texture and odor but lower for taste and overall acceptability compared to MZST. In terms of profitability, SFCP increased feed costs by 5% but resulted in higher margins over feed costs of 12 and 24% for milk and cheese, respectively, compared to MZST. Conclusion: In spite of favorable performance and economic returns of MZST treatment (control treatment), the organoleptic characteristics of the cheese reduced its general acceptance.
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Resumo Antecedentes: A produção de caprinos em todo o mundo tem crescido como forma de melhorar a qualidade de vida rural e reduzir a pegada ambiental; pero há uma necessidade de aumentar a produtividade através de estratégias de alimentação melhoradas. A crescente procura dos consumidores por produtos mais saudáveis mas com características organolépticas semelhantes aos tradicionais, tornou necessário desenvolver estratégias para satisfazer esta necessidade, pelo que é necessário avaliar o efeito de novas forrageiras nas dietas na sua aceitação pelos consumidores. A composição química e organoléptica do leite de cabra varia de acordo com a dieta, o que por sua vez afeta as características do queijo de leite de cabra. Entre os atributos sensoriais mais importantes para os consumidores estão textura, sabor e cheiro. Objetivo: Avaliar o efeito da substituição da palha de milho por feno de girassol associada ao grão-de-bico na alimentação de cabras leiteiras, em termos de rendimento, composição química e aceitabilidade sensorial do queijo, bem como desempenho econômico. Métodos: Vinte e oito cabras leiteiras Saanen foram distribuídas aleatoriamente em dois tratamentos em um experimento de 30 dias em uma fazenda de pequena escala. A ração diária por cabra no tratamento MZST (tratamento controle) consistia em feno de alfafa (200 g/cabra/dia) e concentrado (400 g/cabra/dia) mais 600 g/cabra/dia (50% da ração) de a palha de milho e o tratamento SFCP (tratamento substituiu o feno de girassol-grão moído) continham os mesmos teores de alfafa e concentrado, mas com 600 g/cabra/dia de feno de girassol-grão. O rendimento, a composição e a avaliação sensorial dos queijos in natura feitos com leite de cada tratamento foram registrados e os custos de alimentação e retornos avaliados. As variáveis de composição química dos queijos foram analisadas seguindo um delineamento inteiramente casualizado. Resultados: Houve diferenças significativas no rendimento do queijo e para todas as variáveis de composição química. A avaliação sensorial mostrou que o queijo SFCP teve pontuações significativamente mais altas para textura e odor, mas significativamente mais baixas para sabor e aceitabilidade geral em comparação com o MZST. Em termos econômicos, o SFCP aumentou os custos com alimentação em 5%, mas resultou em margens mais altas sobre os custos com alimentação de 12 e 24% para leite e queijo, respectivamente, em comparação com o MZST. Conclusão: Apesar do desempenho favorável e do retorno econômico com o tratamento MZST (tratamento controle), mudanças nas características organolépticas do queijo reduziram sua aceitação geral.
ABSTRACT
Due to the intense competition in the sector, the dairy market maintains a constant search for innovations. Thus, new technologies are incorporated, and new products are constantly launched, increasing the range of consumer options. In this way, the understanding of consumers' motivations, attitudes, and behaviors in the moments of choice, purchase, and consumption are important for the academic public and food industries. This study used the Text Highlighting methodology to assess Brazilian consumers' explicit attitudes towards using high-intensity ultrasound technology in Minas Frescal cheese processing. In the task, consumers were asked to highlight in a text the terms they "liked" or "disliked" about using high-intensity ultrasound in the Minas Frescal cheese processing. A seven-point Likert scale was also used to assess consumers' attitudinal statements. A high engagement of consumers with the Text Highlighting methodology could be observed (43.8-92.3% of text highlighting), which suggests good intuitiveness of the technique. Including information about the benefits of the emerging technology in the product, mainly on sensory and nutritional properties, may increase positive consumer perception, as it promotes the consumers to express their value judgment in the form of "liked". At the same time, the harms of the traditional processing technique prompted consumers to express their value judgment in the "disliked" highlights. It was observed that information should be in a simple and direct language, as technical terminology in the text did not have a positive effect. The categorizing of consumers according to the sentimental score showed that consumers are still reticent to use emerging technologies in Minas Frescal cheese processing. Consumers' attitudinal statements demonstrated that consumers perceive high-intensity ultrasound as a positive idea and safety technology for Minas Frescal cheese processing. Still, they are not willing to pay premium prices. In conclusion, Text Highlighting produced valuable insights that can be used in communication strategies with Minas Frescal cheese consumers.
Subject(s)
Cheese , Consumer Behavior , BrazilABSTRACT
Small-scale dairy systems require feeding strategies to improve their productivity and sustainability. These systems in central Mexico mostly sell their milk to local artisan cheese makers. Cow diets influence milk and dairy products composition; therefore, the objective was to evaluate the effect on physicochemical characteristics, sensory appraisal, and economic performance of cheese made with milk from cows fed different levels of sunflower silage (SFSL). Treatments were the inclusion of SFSL in the forage DM component of diets (T0 = 0% SFSL; T20 = 20%; T40 = 40%; and, T60 = 60%). Physicochemical composition was analysed by analysis of variance in a completely randomised design and the sensory assessment of the cheese was with a hedonistic five-point scale and the results were analysed by means of descriptive statistics and a radar graph. Partial budgets were used for economic analyses. There were significant differences (P < 0.05) for all physicochemical variables (moisture content, cheese yield, protein, fat content, and pH) of the cheese, with higher values for yield, protein, and fat content in the treatments that included SFSL. Sensory assessment values were in the average perception range of judges. Treatments that included SFSL had lower production costs, higher margins over costs, and higher returns/costs ratios. The inclusion of sunflower silage at 40 and 60% of the forage component of diets for dairy cows in small-scale dairy systems had positive effects. Yields of cheese as well as protein and fat content were higher. There were positive sensory attributes that meant acceptance by consumers, lower production costs, and higher incomes from cheese making.
Subject(s)
Asteraceae , Cheese , Helianthus , Female , Cattle , Animals , Silage/analysis , Lactation/metabolism , Cheese/analysis , Milk/chemistry , Diet/veterinary , Zea mays/chemistryABSTRACT
Electronic devices have been used to describe chemical compounds in the food industry. However, there are different models and manufacturers of these devices; thus, there has been little consistency in the type of compounds and methods used for identification. This work aimed to determine the applicability of electronic nose (e-nose) Cyroanose 320 to describe the differentiation of volatile organic compounds (VOCs) in fresh Mexican cheese (F-MC) formulated with milk from two different dairy cattle breeds. The VOCs were described using a device manufactured by Sensigent and Solid-Phase Micro-extraction (SPME) coupled to GC-MS as a complementary method. The multivariate principal components analysis (PCA) and the partial least squares discriminant analysis (PLS-DA) were used to describe the relationships of VOCs to electronic nose data, sensory data, and response levels. In addition, variable importance in projection (VIP) was performed to characterize the e-nose signals to the VOCs. The e-nose distinguishes F-MC prepared with milk from two dairy breeds. Sensor number 31 correlated with carboxylic acids most in F-MC from Jersey milk. The HS-SPME/GC-MS identified eighteen VOCs in F-MC made with Holstein milk, while only eleven VOCs were identified for F-MC made with Jersey milk. The more significant peaks in both chromatogram analyses were Propanoic acid, 2-methyl-, 1-(1,1-dimethylethyl)-2-methyl-1,3-propanediyl ester in cheese made from Holstein milk and Propanoic acid, 2-methyl-, 3-hydroxy-2,4,4-trimethylpentyl ester in Jersey milk cheese. Both compounds are considered essential carboxylic acids in the dairy industry. Thus, sensor 31 in the electronic nose Cyranose 320 increased its response by essential carboxylic acids identified by HS-SPME/GC-MS as a complementary method. The e-nose Cyranose 320 is potentially helpful for evaluating fresh Mexican cheese authentication independent of cows' milk samples from different breeds.
ABSTRACT
The effect of ultrasound-treated fresh raw milk upon yield, physicochemical and microbiological quality of Oaxaca cheese was evaluated under a factorial design. The ultrasound frequencies tested were 25 and 45 kHz, during 15 or 30 min. The cheeses made with the ultrasonicated milk (30 min, high-intensity ultrasound, HIU) had greater luminosity without significant changes in hue or chroma, as compared to the controls with no HIU. The yield improved significantly (by up to 2.8 kg/100 L of milk), as the ultrasound treatment time increased. Such cheese yield is attributable to the higher protein content, which was up to 1.5% higher, after sonication. Long-treatment time (30 min) at 25 kHz significantly lowered mesophilic bacteria counts down to limits allowed by current regulations and favors the growth of lactic acid bacteria (LAB) while lowering mold and yeast counts. The absence of E. coli and Salmonella spp. and the decrease in S. aureus counts in Oaxaca cheese were attributed to the mixing of the paste with hot water, inherent to the traditional elaboration process, and to the antagonistic effect of the ultrasound-triggered increased LAB on pathogenic bacteria. Since the artisanal elaboration of Oaxaca cheese does not comply with the current Mexican regulations regarding mesophiles, ultrasound could be a suitable technology to protect its genuine elaboration process with raw milk.
ABSTRACT
Physical-chemical characteristics of Minas Frescal cheese (MFC) favor the growth of Staphylococcus spp. and allow the production of enterotoxins by specific strains. Here, we aimed to characterize the physical-chemical aspects (pH, storage temperature, and salt content) and the presence of Staphylococcus spp. in MFC samples (n = 50) to support a modeling study for the growth by this microorganism. Coagulase-positive staphylococci isolates were obtained and subjected to PCR assays to identify them as Staphylococcus aureus (nuc) and to detect staphylococcal enterotoxin-related genes (sea, seb, sec, sed, see). Staphylococcus aureus growth kinetics (maximum growth rate, Grmax, and lag time) were predicted based on ComBase model and MFC physical-chemical aspects. Mean counts of Staphylococcus spp. ranged from 3.3 to 6.7 log cfu/g, indicating poor hygiene practices during production. Selected isolates (n = 10) were identified as S. aureus, but none presented classical enterotoxin-related genes. pH, temperature, and salt content ranged from 5.80 to 6.62, 5°C to 12°C, and 0.85% to 1.70%, respectively. The Grmax values ranged from 0.012 to 0.419 log cfu/g per h. Independent of the storage temperature, the lowest Grmax values (0.012 to 0.372 log cfu/h) were obtained at pH 5.80 associated with salt content of 1.7%; independent of the pH and salt content, the best temperature to avoid staphylococcal growth was 7.5°C. Hygienic conditions during MFC production must be adopted to avoid staphylococcal contamination, and storage at temperatures lower than 7.5°C can prevent staphylococcal growth and the potential production of enterotoxins.
Subject(s)
Cheese , Animals , Brazil , Enterotoxins/analysis , Enterotoxins/genetics , Food Microbiology , Staphylococcus , Staphylococcus aureusABSTRACT
This study aimed to evaluate the effect of Lacticaseibacillus casei 01 as a probiotic culture on the production of volatile organic compounds and metabolic profile of Minas Frescal cheese. Lactose (α-lactose and ß-lactose), fatty acids (unsaturated and saturated), citric acid, tryptophan, and benzoic acid were the main compounds. Compared with the control cheese, probiotic cheese was characterized by the highest concentration of tryptophan and presented a higher number of volatile acids. The control cheese was characterized by the highest concentration of benzoic acid and fatty acids, resulting in a higher number of volatile alcohols and esters. No differences were observed for α-lactose, ß-lactose, and citric acid contents. A clear separation of probiotic and control Minas Frescal cheese was obtained using 1H nuclear magnetic resonance spectra, demonstrating that the addition of probiotic culture altered the metabolic profile of Minas Frescal cheese. Overall, the findings suggested that the addition of probiotic culture promoted the proteolysis in the fresh cheeses, decreased the lipolysis, and altered the volatile compounds. Furthermore, nuclear magnetic resonance spectroscopy coupled to chemometrics tools could be used to differentiate probiotic and conventional cheeses.
Subject(s)
Cheese , Probiotics , Volatile Organic Compounds , Animals , Cheese/analysis , Magnetic Resonance Spectroscopy , Metabolome , Volatile Organic Compounds/analysisABSTRACT
INTRODUCTION: Minas fresh cheese (MFC), a Brazilian white cheese, is one of the most popular cheeses nationwide. Studies have shown that Listeria monocytogenes occurrence in this product is generally low, while high populations of coliforms can be found. This study aimed to evaluate the influence of coliforms in the behavior of L. monocytogenes in MFC. METHODS: Pasteurized milk was inoculated with L. monocytogenes and coliforms, and the acidification was made by lactic acid or by the addition of a starter culture. The cheeses of each production were divided into 3 groups and stored at 5 ºC, 12 ºC and cycles of 5 ºC followed by 25 ºC. In predetermined days, samples were taken and L. monocytogenes, coliforms and lactic acid bacteria populations were evaluated, besides the pH, water activity (aw), titratable acidity and NaCl concentration. RESULTS: The inhibition of L. monocytogenes in the presence of coliforms was observed (p < 0.05), except for those samples prepared with lactic acid and stored at temperature cycles. The values of pH and aw were not sufficiently low to cause inhibition; however, titratable acidity was higher in cheeses containing coliforms. In vitro tests containing lactic acid and L. monocytogenes showed that the bacterium is sensitive to concentration of lactic acid ≥ 0.3%, indicating that lactic acid produced by coliforms strongly influences the population of L. monocytogenes. CONCLUSIONS: Thus, it can be concluded that coliforms negatively impact populations of L. monocytogenes in MFC. We strongly recommend that producers of MFC adopt good hygiene practices to not only avoid contamination with L. monocytogenes, but also coliforms.
Subject(s)
Cheese/microbiology , Enterobacteriaceae/physiology , Lactobacillales/physiology , Listeria monocytogenes/isolation & purification , Animals , Antibiosis , Brazil , Cheese/analysis , Colony Count, Microbial , Food Microbiology , Lactic Acid/analysis , Listeria monocytogenes/physiology , Milk/microbiology , Sodium Chloride/analysis , Temperature , Water/analysisABSTRACT
ABSTRACT: This study investigated the presence of nontuberculous mycobacteria (NTM) for the first time in two types of unpasteurized fresh cheese produced in the state of Michoacan, Mexico. We tested for this pathogen, along with the others, to broaden the study of microbiological quality in 60 samples of cheese, 30 fresh and 30 Adobera, which were collected from six artisanal cheese factories (ACFs). The hygienic conditions of these establishments and the practices of cheese manufacture were generally poor. Although Mycobacterium bovis was not detected, four cheese samples harbored NTM isolates. The four NTM isolates were identified using three molecular markers (hsp65, rrs, and rpoB genes) that corresponded to Mycolicibacterium fortuitum (n = 3) and Mycolicibacterium mageritense (n = 1). All 60 cheese samples analyzed had unsatisfactory microbiological quality according to the Mexican Official Guideline. Regarding fresh cheeses, all 30 samples analyzed were positive for aerobic mesophilic bacteria, total coliforms, fecal coliforms, and yeasts and molds. Escherichia coli and Staphylococcus aureus were present in 23 and 21 samples, respectively. Listeria monocytogenes was identified in a sample and was isolated from a bulk milk tank in the same ACF. With regard to Adobera cheeses, all samples were positive for aerobic mesophilic bacteria, total coliforms, fecal coliforms, yeasts and molds, and S. aureus. E. coli was isolated from 28 samples. Salmonella was isolated from a sample and from a wooden shovel used in the manufacture of the cheeses in the same ACF. Thus, the consumption of unpasteurized fresh cheese may represent a public health risk. Because of this, health authorities should enforce the legislation that forbids the processing of cheese with unpasteurized milk and encourage producers to follow good manufacturing practices from original ingredients, through the production process of the cheese, to its sale to assure a safe product.
Subject(s)
Cheese , Listeria monocytogenes , Animals , Cheese/analysis , Escherichia coli , Food Microbiology , Mexico , Milk , Mycobacteriaceae , Nontuberculous Mycobacteria , Salmonella , Staphylococcus aureusABSTRACT
Buffalo milk presents higher proteins and lipids concentration than cow milk, which provides a better yield in cheese-making production and products with considerable sensory approval. However, buffalo milk is not regularly available throughout the year due to different handling conditions. Thus, to guarantee the supply of buffalo milk dairy products during the year, the addition of bovine milk is an alternative. Therefore, this study aimed to test the effect of a buffalo and bovine milk mixture for the Minas Frescal cheese elaboration by physico-chemical, sensory analysis and obtaining yield. The raw material was analysed for the parameters of acidity, density, fat, total solids and solid-not-fat. There were 3 Minas Frescal cheeses elaborated from 3 formulations: 100% buffalo milk, 100% bovine milk and the mixture of 50% of each milk. The cheeses were submitted to the Gravimetric and Gerber methods to obtain values of moisture and fat, as well as to obtain, indirectly, fat in dry matter. For bovine and buffalo milk, the parameters evaluated (acidity, density, fat, total solids and solids-not-fat) complied with Brazilian legislation and parameters described in the literature. For the bovine, mixed and buffalo fresh cheeses, values were obtained, respectively, for moisture (74.04, 60.93 and 63.61), fat in dry matter (44.35, 42.23 and 46.03) and cheese yield (27, 20.8 and 24.2), indicating a higher yield for the bovine Minas Frescal cheese and higher fat content for the buffalo cheese. The overall acceptance of the mixed Minas Frescal cheese was significantly superior to the bovine and buffalo cheese. The parameters of colour, appearance, texture, flavour and overall acceptance were above 8 points in the hedonic scale ('moderately liked' to 'extremely liked'), and the aroma attribute scored was above 7 ('I enjoyed regularly' to 'moderately liked'). Therefore, the elaboration of Minas Frescal cheese from the mixture of 2 matrices (buffalo and bovine milk) demonstrated technological viability with the potential to meet the demands of the consumer market.
O leite de búfala possui maior porcentagem de todos os componentes tornando-o uma matéria-prima adequada com potencial para fornecer um maior rendimento e qualidade nutricional na produção de queijo. No entanto, o leite de búfalo não está disponível regularmente ao longo do ano devido a diferentes condições de manejo. Assim, para garantir a oferta de produtos lácteos com leite de búfala independentemente da época, a adição de leite bovino pode ser vista como uma alternativa. Logo, este trabalho teve como objetivo testar o efeito da mistura do leite de búfalo e bovino na elaboração do queijo Minas Frescal por meio de análises físico-químicas e sensoriais e obtenção do rendimento economico. A matéria-prima foi analisada quanto aos parâmetros: acidez titulável, densidade, gordura, sólidos totais e sólidos totais desengordurados. Três variedades de queijo Minas Frescal foram elaboradas a partir de três formulações: 100% de leite de búfala, 100% de leite bovino e da mistura de 50% de cada leite. Os queijos foram submetidos aos métodos Gavimetric e Gerber para obtenção de umidade e gordura, bem como, indiretamente, para obtenção de matéria gorda no extrato seco. Para o leite bovino e de búfala, os parâmetros avaliados (acidez titulável, densidade, gordura, sólidos totais e sólidos totais desengordurados) estavam de acordo com a legislação brasileira e parâmetros descritos na literatura. Para os queijos bovino, misto e de búfala, foram obtidos, respectivamente, para: umidade (74,04; 60,93 e 63,61), gordura na matéria seca (44,35; 42,23 e 46,03) e rendimento econômico (27, 20,8 e 24,2) indicando maior rendimento o queijo Minas Frescal bovino e maior teor de gordura para o queijo búfalo. A aceitação global do queijo Minas Frescal misto foi significativamente superior ao do queijo bovino e bubalino. Os parâmetros de cor, aparência, textura, sabor e aceitabilidade global foram acima de 8 pontos (entre "gostei moderadamente" e "extremamente gostei") e o atributo aroma obteve pontuação acima de 7 ("gostei regularmente" para "gostei moderadamente"). Portanto, a elaboração do queijo Minas Frescal da mistura de leite bovino ao búfalo demonstrou potencial para atender as demandas do mercado consumidor.
Subject(s)
Buffaloes , Cheese , Breast-Milk SubstitutesABSTRACT
High-intensity ultrasound could be an alternative to pasteurization for cheeses made with fresh raw milk, the properties of which must be preserved as part of their intangible cultural heritage, such as Panela cheese in Mexico. This research aimed to study the effect of the amplitude (50% and 100%) and application time (0, 5, and 10 min) of ultrasound treatment of fresh raw milk, on the yield and microbiological and physicochemical qualities of Panela cheese after 24 h of storage at 4 °C. The yield was increased to 24.29% with 10 min of ultrasonication, although the amount of exudate was higher in the ultrasonic product than in the control (20.33%). As the ultrasonication time increased, the yellowness (b*) increased significantly, while the hue angle decreased (with values close to 90°), resulting in evident yellow tones in cheeses made with milk treated for 10 min. The pH significantly increased from 6.6 to 6.74 with 5 min of ultrasound, but decreased to 6.37 with 10 min of ultrasonication. Although no significant differences were found in fat content, the protein significantly increased with 5 min of sonication, but it decreased markedly when ultrasound was applied for 10 min. Ultrasound treatment with amplitudes of 50% effectively decreased the counts of coliform bacteria regardless of ultrasonication time. However, the mesophilic bacteria increased by a 0.9 log with an amplitude of 100% and 10 min treatment. The results showed that ultrasound improved the yield and microbial, nutritional, and physicochemical properties of Panela cheese.
ABSTRACT
RESUMEN Una tendencia actual en la elaboración de quesos es sustituir la grasa láctea por su alto contenido de ácidos grasos saturados (AGS), con lípidos de origen vegetal y el aguacate por su alto contenido de ácidos grasos insaturados(AGI), principalmente, el ácido oleico y fitosteroles (campesterol, β- Sitosterol), ha sido valorado al promover beneficios saludables al consumidor. El objetivo de este estudio fue evaluar, con jueces, el agrado o desagrado, mediante prueba hedónica, los quesos elaborados con sustitución de grasa y analizar el perfil de textura (TPA). Se analizaron los quesos elaborados con tres niveles de pulpa, mediante prueba hedónica de 5 puntos, con 109 jueces y el análisis de perfil de textura con texturometro, modelo TA-XT2i. El T4, con el 18% de pulpa adicionada, fue el que más agradó, de acuerdo con la prueba DMS, al determinar la aceptación de los quesos, aunque no se encontró diferencias entre el T3 y el T4 y, el T2, el que menos gustó. En el análisis de perfil de textura, se encontró diferencias significativas respecto al control; la pulpa de aguacate, como sustituto de grasa en los quesos, generó bajos valores en los parámetros texturales; los quesos retienen alta humedad y bajo contenido de grasa, obteniendo un producto desmoronable, debido a la modificación de la matriz de la caseína, que es la que da rigidez a los quesos.
ABSTRACT A current trend in cheese making is to substitute milk fat for its high content of saturated fatty acids (SFA), with lipids of vegetable origin and avocado for its high content of unsaturated fatty acids (AGI) mainly oleic acid and phytosterols. (campesterol, β-Sitosterol), has been valued by promoting healthy benefits to the consumer. The objective of this study was to evaluate with judges the liking or dislike of the cheeses made with fat replacement and to analyze the texture profile (TPA). The cheeses elaborated with three levels of avocado pulp were analyzed by means of a 5point hedonic test with 109 judges and the analysis of texture profile with texturometer model TA-XT2i. The T4 with the 18% added pulp was the one liked most according to the DMS test when determining the acceptance of the cheeses, although no differences were found between the T3 and the T4; the T2 was the least liked product. In the texture profile analysis, significant differences were found with respect to the control; the avocado pulp as a substitute for fat in the cheeses generated low values in the textural parameters, the cheeses retain high humidity and low fat content, obtaining a crumbly product, due to the modification of the casein matrix which is the one that gives rigidity to the cheeses.
ABSTRACT
Introducción. Se presenta una propuesta de signo distintivo para la producción y comercialización de queso costeño de alto impacto en el departamento del Atlántico y en la región Caribe colombiana. Objetivo. Proponer a los productores de queso costeño, un modelo de producción y comercialización del producto, que siente las bases para convertir la quesería artesanal en un instrumento de desarrollo regional, a partir de la fabricación de un producto inocuo de base biotecnológica. Materiales y métodos. Estudio de tipo descriptivo abordado desde los aspectos socio-cultural y biotecnológico, para la identificación de valores colectivos relacionados con tradición quesera, preferencias de producción, asociatividad, cumplimiento de normas legales, signo distintivo y uso de cultivos lácticos autóctonos en sus procesos productivos para incorporar características del queso típico de la región. Resultados. Mediante el desarrollo de un signo distintivo es posible no solo el posicionamiento del queso costeño en el mercado como producto de alto valor, sino dejar atrás la indiferenciación actual propia de un producto básico, y lograr la reducción de riesgo de contaminación, teniendo en cuenta el valor agregado que representan los inóculos microbianos como innovación biotecnológica en la calidad del producto. Conclusión. El modelo presentado convenció al productor de que bajo el signo distintivo su producto tiene mayor valor agregado y, en consecuencia, podrá obtener un precio mayor al actual.
Introduction. A distinctive sign proposal is presented for high-impact production and marketing of coast cheese in the state of Atlántico and in the Colombian Caribbean region. Objective. To propose coast cheese producers a production and marketing model of the product; a model which lays the foundation to covert craft cheese factories into a regional development instrument from the manufacture of a biotechnological-based innocuous product. Materials and methods. Descriptive research addressed from social-cultural and biotechnological aspects for the identification of collective values associated to cheese-making tradition, production preferences, association capacity, compliance with legal regulations, distinctive sign, and use of native dairy cultures in their production processes in order to incorporate characteristics of the typical cheese of the region. Results. Through the development of a distinctive sign, it is possible not only to position the coast cheese in the market as a high-value product but also to left behind the present non-differentiation typical of a basic product and to achieve the decrease of contamination risks, bearing into account the value added brought by microbial inoculation as biotechnological innovation in the product quality. Conclusion. The model shown has convinced the producers that under the distinctive sign their product has better value added and then they would be able to gain a higher price.
Introdução. Se apresenta uma proposta de signo distintivo para a produção e comercialização de queijo litorâneo de alto impacto no departamento do Atlântico e na região do Caribe colombiano. Objetivo. Propor aos produtores de queijo litorâneo, um modelo de produção e comercialização do produto, que sente as bases para converter a indústria do queijo artesanal num instrumento de desenvolvimento regional, a partir da fabricação de um produto inócuo de base biotecnológica. Materiais e métodos. Estudo de tipo descritivo abordado desde os aspectos sociocultural e biotecnológico, para a identificação de valores coletivos relacionados com a tradição da indústria do queijo, preferências de produção, associatividade, cumprimento de normas legais, signo distintivo e uso de cultivos lácteos autóctones nos seus processos produtivos para incorporar características do queijo típico da região. Resultados. Mediante o desenvolvimento de um signo distintivo é possível não só o posicionamento do queijo litorâneo no mercado como produto de alto valor, senão deixar atrás a indiferença atual própria de um produto básico, e conseguir a redução do risco de contaminação, tendo em conta o valor agregado que representam os inócuos microbianos como inovação biotecnológica na qualidade do produto. Conclusão. O modelo apresentado convenceu ao produtor de que sob o signo distintivo seu produto tem maior valor agregado e, por consequência, poderá obter um preço maior ao atual.
ABSTRACT
Introduction: Brucellosis is one of the most frequent zoonosis in most parts of the world. This zoonosis remains a great problem to public health in developing countries, although developed countries have successfully controlled it. Mexico still shows a high annual brucellosis incidence in humans; thus, the country is considered around the world as an endemic brucellosis country. Aim: To describe the connection/association between this zoonosis and the current epidemiological situation in the Mexican population. Methods: Perusal of research reports, epidemiological studies and veterinarian reviews performed in Mexico, using data bases such as PubMed, Thompson Reuters, Mesh research. Conclusion: The risk of infection by Brucella in Mexico is associated with the consumption of unpasteurized dairy products, mainly fresh cheeses.
Introducción: La brucelosis es una de las enfermedades zoonóticas más frecuentes en la mayor parte del mundo. Mientras que en los países desarrollados han logrado con éxito su control, en los países en vías de desarrollo continúa siendo un gran problema de salud pública. México continúa presentando alta incidencia anual de brucelosis en humanos, por lo que es considerado un país endémico de brucelosis. Objetivo: Describir la relación de esta zoonosis con la situación epidemiológica actual en la población de México. Material y Métodos: Consulta de reportes de investigación, estudios epidemiológicos y revisiones veterinarias, realizadas en México, a través de bases de datos como PubMed, Thompson Reuters y Meshresearch. Conclusión: El riesgo del contagio de Brucella spp. en México está asociado al consumo de productos lácteos sin pasteurizar, principalmente quesos frescos.
Subject(s)
Humans , Animals , Brucellosis/epidemiology , Zoonoses , Goat Diseases/epidemiology , Brucellosis/transmission , Brucellosis/veterinary , Goats , Incidence , Mexico/epidemiologyABSTRACT
Staphylococci are considered a major concern in dairy plants mainly due to the intensive production flow, automation of processing plants and increased demand in the microbiological quality of dairy products. This study aimed to identify S. aureus strains isolated from three Brazilian dairy plants, evaluate the influence of time, temperature and contact surface on the bacterial adhesion process, as well as the efficiency of simulated hygiene and sanitation protocol in removing adhered cells. For genotypic analyses, the presence of icaA and icaD in strains was evaluated. Adherence assays were performed in biofilm reactor, comparing the influence of 2 temperatures (5°C and 35°C), 2 surfaces (stainless steel and polypropylene) and 4 contact times (3, 6, 12h and post-sanitization). To evaluate the process effectiveness in removing adhered cells, neutral detergent and sanitizing agent based on sodium hypochlorite were used in order to simulate the situation observed in one of the dairy plants analyzed. The presence of icaA and icaD genes was determined in 75.3% and 77.6% of strains, respectively; 70.6% of isolates showed both genes, whereas 17.6% showed no genes. Genes for enterotoxin production were found in all samples, relating to SEG and SEH toxins. The number of cells adhered on both surfaces was about 3 and 6 log10 CFU/cm2 at temperatures of 5°C and 35°C, respectively, for most situations evaluated, with significant increase over the evaluation period. In general, the temperature of 35°C favored greater adherence of S. aureus. At 5°C, there was a considerable number of adhered cells, but in populations significantly lower than those observed at 35°C. The cleaning and sanitizing protocol was ineffective in removing adhered cells; better performance of sodium hypochlorite was observed at 5°C, which should be related to lower adherence observed at this temperature. Thus, the process was not able to reduce the number of S. aureus bacteria adhered on both surfaces to safe levels under the conditions evaluated.
Subject(s)
Bacterial Adhesion/drug effects , Biofilms/drug effects , Detergents/pharmacology , Disinfectants/pharmacology , Enterotoxins/genetics , Sodium Hypochlorite/pharmacology , Staphylococcus aureus/drug effects , Bacterial Adhesion/physiology , Brazil , Dairying , Staphylococcal Infections/prevention & control , Staphylococcus aureus/genetics , Staphylococcus aureus/isolation & purificationABSTRACT
Introducción: El quesillo es un alimento muy consumido en la población por sus características nutritivas y de inocuidad. Sin embargo, estas cualidades pierden relevancia si no se respetan condiciones adecuadas en su elaboración y almacenamiento. Objetivo: Evaluar la inocuidad microbio-lógica de quesillos comerciales y artesanales expendidos en Chillán. Metodología: Se analizaron 80 muestras de quesillo: 40 comerciales (marca 1 y 2) y 40 artesanales (marca 3 y 4). Se cuantificó Enterobacteriaceae (ENT) y Escherichia coli mediante las NCh 2676 y 2636 (2002). Salmonella, Staphylococcus aereus y Listeria monocytogenes utilizando NCh 2675, 2671 (2002) e ISO 11290-1: 1996 (rev 2004) y confirmadas por PCR. Cronobacter spp por medio de multilocus sequence typing (MLST) con criterios de http://www.pubmlst.org/cronobacter. Los requisitos de higiene del personal y expendio con listas de chequeo de acuerdo al RSA. Resultados: Las medianas globales de ENT fueron 30 000 000 UFC/g (2 000 000 - 300 000 000) y para E. coli de 450 UFC/g NMP/g (33 - 1 100), no existiendo diferencias significativas en los recuentos para ambos indicadores por marca y lugar de expendio (p>0.05). El cumplimento de requisitos de higiene del personal y expendio fue 50%. La positividad de L. monocytogenes fue 8.8%, no detectando Salmonella spp y S. aureus. Se aislaron 8 cepas sospechosas de Cronobacter spp las que fueron identificadas como Franconibacter helveticus. Conclusiones: Los quesillos evaluados no cumplen los criterios microbiológicos del RSA no siendo aptos para el consumo. La presencia de L. mono-cytogenes es un claro riesgo de salud en grupos de población hipersensible que consumen este alimento.
Introduction: Fresh cheese is consumed because of its healthy, nutritional, and safety characteristics. These features become less relevant when appropriatepreparation and storage conditions are not met. Objective: The objective was to evaluate the microbiological safety of commercial and artisanal fresh cheeses sold in the city of Chillán. Methods: A total of 80 fresh cheese samples were analyzed: 40 commercial (brands 1 and2) and 40 artisanal (brands 3 and 4). Enterobacteriaceae (ENT) and Escherichia coli were quantified by NCh 2676 and 2636 (2002). Salmonella, Staphylococcus aureus, and Listeria monocytogenes used NCh 2675, 2671 (2002), ISO 11290-1 (1996 rev 2004), and were confirmed by PCR. Cronobacter spp was identified by multilocus sequence typing (MLST) using criteria from http://www.pubmlst.org/cronobacter. Furthermore, staff and sale hygiene requirements were identified with Sanitary Food Regulations (SFR) checklists. Results: Overall ENT medians were 30 000 000 UFC/g (2 000 000 - 300 000 000) and E. coli were 450 UFC/g NMP/g (33 - 1 100); there were no significant differences in counts for both brand and sale location indicators (p>0.05). Compliance with SFR hygiene requirements was 50%. Positivity of L. monocytogenes was 8.8%; Salmonella spp and S. aureus were not detected. Suspected Cronobacter spp strains were isolated and identified as Franconibacter helveticus. Conclusions: The evaluated fresh cheeses did not meet SFR microbiological criteria and were therefore not safe to eat. The presence of L. monocytogenes is clearly a health risk in hypersensitive population groups that consume this food.
Subject(s)
Cheese/microbiology , International Health Regulations , Food Safety , Food Microbiology , Dairy ProductsABSTRACT
A chitosan from biologically obtained chitin was successfully grafted with d,l-lactic acid (LA) in aqueous media using p-toluenesulfonic acid as catalyst to obtain a non-toxic, biodegradable packaging material that was characterized using scanning electron microscopy, water vapor permeability, and relative humidity (RH) losses. Additionally, the grafting in chitosan with LA produced films with improved mechanical properties. This material successfully extended the shelf life of fresh cheese and inhibited the growth of Listeria monocytogenes during 14 days at 4 °C and 22% RH, whereby inoculated samples with chitosan-g-LA packaging presented full bacterial inhibition. The results were compared to control samples and commercial low-density polyethylene packaging.
Subject(s)
Cheese/microbiology , Chitosan/pharmacology , Food Packaging , Listeria monocytogenes/drug effects , Chitin/chemistry , Chitosan/chemistry , Food Microbiology , Humans , Lactic Acid/chemistry , Lactic Acid/pharmacology , Listeria monocytogenes/pathogenicityABSTRACT
Listeria monocytogenes is a pathogen frequently found in dairy products. Its control in fresh cheeses is difficult, due to the psychrotrophic properties and salt tolerance. Bacteriocinogenic lactic acid bacteria (LAB) with proven in vitro antilisterial activity can be an innovative technological approach but their application needs to be evaluated by means of in situ tests. In this study, a novel bacteriocinogenic Lactococcus lactis strain ( Lc . lactis DF4Mi), isolated from raw goat milk, was tested for control of growth of L. monocytogenes in artificially contaminated fresh Minas type goat cheese during storage under refrigeration. A bacteriostatic effect was achieved, and counts after 10 days were 3 log lower than in control cheeses with no added LAB. However, this effect did not differ significantly from that obtained with a non-bacteriocinogenic Lc. lactis strain. Addition of nisin (12.5 mg/kg) caused a rapid decrease in the number of viable L. monocytogenes in the cheeses, suggesting that further studies with the purified bacteriocin DF4Mi may open new possibilities for this strain as biopreservative in dairy products.
Subject(s)
Antibiosis , Bacteriocins/metabolism , Cheese/microbiology , Goats , Lactococcus lactis/isolation & purification , Listeria monocytogenes/drug effects , Milk/microbiology , Animals , Bacterial Load , Food Preservation/methods , Food Safety/methods , Lactococcus lactis/metabolismABSTRACT
Listeria monocytogenes is a pathogen frequently found in dairy products. Its control in fresh cheeses is difficult, due to the psychrotrophic properties and salt tolerance. Bacteriocinogenic lactic acid bacteria (LAB) with proven in vitro antilisterial activity can be an innovative technological approach but their application needs to be evaluated by means of in situ tests. In this study, a novel bacteriocinogenic Lactococcus lactis strain (Lc. lactis DF4Mi), isolated from raw goat milk, was tested for control of growth of L. monocytogenes in artificially contaminated fresh Minas type goat cheese during storage under refrigeration. A bacteriostatic effect was achieved, and counts after 10 days were 3 log lower than in control cheeses with no added LAB. However, this effect did not differ significantly from that obtained with a non-bacteriocinogenic Lc. lactis strain. Addition of nisin (12.5 mg/kg) caused a rapid decrease in the number of viable L. monocytogenes in the cheeses, suggesting that further studies with the purified bacteriocin DF4Mi may open new possibilities for this strain as biopreservative in dairy products.