ABSTRACT
Considering the widespread consumption of milk powder by the general population as well as the lack of studies on the toxicity of such industrialized foods, this study evaluated the cytotoxic and genotoxic potential of powdered milk from four reputed companies in the food market of Brazil and other South American countries. Milk samples were evaluated in root meristem cells of Allium cepa L., at concentrations of 0.065 and 0.13 g/mL, for 24 and 48 hours of exposure; and by means of cell viability in culture of cells of normal lineage, via MTT test, for 24 hours, at concentrations of 0.016; 0.032; 0.065 and 0.13g/mL. The concentration 0.13 g/mL was the one suggested for consumption in all milk packages evaluated in this study. In A. cepa, we observed that the milks, at both concentrations and at the two exposure times investigated, reduced the cellular proliferation of root meristems demonstrating a significant cytotoxicity. Furthermore, 0.13g/mL milks at the exposure time of 24h induced an expressive frequency of cellular alterations in the plant tissue, showing to be genotoxic. In the in vitro evaluation, three milks at 0.065 g/mL and all milks at 0.13 g/mL have significantly reduced cell viability, proving to be cytotoxic to the analyzed cell culture. Therefore, under the studied conditions, the powdered milks evaluated caused significant genetic instability to the cells of the test systems used.
Devido o amplo consumo de leite em pó pela população em geral, bem como, a carência de estudos sobre a toxicidade de tais alimentos industrializados, objetivou-se na presente pesquisa avaliar o potencial citotóxico e genotóxico de leites em pó provenientes de quatro empresas de reconhecida atuação no mercado de alimentos brasileiro e de outros países da América do sul. As amostras de leite foram avaliadas em células meristemáticas de raízes de Allium cepa L., nas concentrações 0,065 e 0,13g/mL, por 24 e 48 horas de exposição; e por meio da viabilidade celular em cultura de células de linhagem normal, via teste MTT, por 24 horas, nas concentrações 0,016; 0,032; 0,065 e 0,13g/mL. A concentração 0,13 mL/kg foi a sugerida para consumo em todas embalagens de leites avaliados neste estudo. Em A. cepa, verificou-se que os leites, nas duas concentrações e nos dois tempos de análise considerados, reduziram a proliferação celular dos meristemas de raízes demonstrando citotoxicidade significativa. Ainda, os leites na concentração 0,13g/mL induziram, no tempo de exposição 24h, frequência expressiva de alterações celulares ao tecido vegetal, mostrando-se genotóxicas. Na avaliação in vitro, três leites na concentração 0,065g/mL e todos na concentração 0,13g/mL reduziram significativamente a viabilidade celular mostrando-se citotóxicos a cultura de células analisada. Portanto, nas condições de estudo estabelecidas, os leites em pó avaliados causaram significativa instabilidade genética as células dos sistemas testes utilizados.
Subject(s)
Cell Survival , Dairy Products/toxicity , Food, Preserved , Mutagenicity TestsABSTRACT
A simple, accurate and sensitive high-performance liquid chromatography (HPLC) method was developed, validated and applied to the determination of either theophylline or paracetamol in milk-based samples. The method allowed drug quantification in fresh and powdered milk with a relatively short run time of analysis and it was also successfully applied to the quantification of the drugs in solid dosage forms intended for pediatric use. Moreover, the main significant advantages over other published works are the simplicity of the sample preparation, reduced assay time and sample loss. The method meets the International Conference on Harmonization guideline for analytical methods validation regarding specificity,linearity,accuracy,precision, specificity and robustness as required by health authorities and applied by industry while designing and marketing new drug products.The technique encompasses the separation of the analytes with a reverse phase C18column under isocratic conditions and UV detection at 272 nm and 243 nm,respectively,for theophylline and paracetamol. The lower limit of quantification for both drugs was determined as 0.2μg/mL and the between-batch accuracy was 99.7%.This HPLC method allows quantification of theophylline and paracetamol in milk matrices and it can be applied in the design,development and production of milk-based pediatric dosage forms.
ABSTRACT
La leche en polvo es un producto de alto consumo humano que no precisa de ser conservado en frío, no obstante, diversos microorganismos pueden deteriorarlo. En la población costarricense, también se observa este alto consumo, por la facilidad del alimento para transporte, preparación y su costo competitivo. Bacillus cereus es una bacteria potencialmente patógena asociada a este tipo de producto, capaz de desarrollar toxinas dependiendo de la presencia o ausencia de los respectivos genes codificantes. En este estudio se determinó la presencia de los genes toxigénicos nheA, nheB y nheC en cepas de B. cereus aisladas de leche deshidratada vendida en el mercado nacional costarricense.Se examinaron cinco lotes diferentes, de diez marcas comerciales de leche en polvo distribuidos en el área metropolitana de San José Costa Rica. Se procedió a cuantificar B. cereus en las muestras de leche en polvo mediante la técnica de Número Más Probable (NMP) e identificar los aislamientos utilizando el equipo automatizado Vitek®. Adicionalmente, se determinó la presencia de los genes nheA, nheB y nheC mediante la técnica de PCR. La frecuencia de aislamiento de Bacillus cereus en las muestras de leche en polvo analizadas alcanzó un 50%, con cantidades que oscilaron entre 3 y >100 NMP/g. Se recuperaron 19 cepas de B. cereus aisladas, cinco fueron positivas para los tres genes toxigénicos, lo cual revela la presencia de B. cereus potencialmente toxigénico en leches deshidratadas del mercado nacional, lo que representa un riesgo para la salud pública.
Powdered milk is a frequently consumed product that does not need to be kept under cold conditions. Nevertheless, different microorganisms may contaminate it. Powdered milk is a highly consumed product by Costa Rican population, and Bacillus cereus is a potentially pathogenic bacteria associated to it, with the ability to develop toxins depending on the presence of the respective codifying genes. The aim of this study was to determine the presence of the toxigenic genes nheA, nheB and nheC from B. cereus strains, found in powdered milk sold at the Costa Rican national market. Five different lots of ten brands of powdered milk, distributed in the metropolitan area of San José, Costa Rica were analyzed. B cereus load was quantified using the Most Probable Number technique and identified using the Vitek® system. The presence of the toxigenic genes was determined using the PCR technique. The isolation frequency of this bacteria in the powdered milk samples analyzed reached 50%, with populations ranging from 3 to >100 MPN/g. Five out from nineteen strains were found positive for the three toxigenic genes, indicating contamination with potentially toxigenic B. cereus in powdered milk distributed in the national market, and an important risk for public health.
Subject(s)
Animals , Bacillus cereus/isolation & purification , Enterotoxins/genetics , Food Microbiology , Milk/microbiology , Bacillus cereus/genetics , Colony Count, Microbial , Costa Rica , DNA, Bacterial/genetics , Enterotoxins/isolation & purification , Polymerase Chain ReactionABSTRACT
Los métodos tradicionales para identificar Salmonella sp. se basan en el empleo de medios de cultivo que permiten la recuperación del microorganismo, el aislamiento en medios selectivos, la identificación bioquímica y caracterización serológica. Estos métodos son dispendiosos, tienen baja especificidad, baja sensibilidad y consumen mucho tiempo. El principal objetivo de este trabajo fue estandarizar y optimizar la técnica de PCR para detectar Salmonella sp. en 12 horas, a partir de ADN de cultivos puros y en muestras de leche en polvo, inoculadas intencionalmente con 200, 20 y 2 UFC/mL. Para la extracción del ADN se estudió la conveniencia de fenol:cloroformo:alcohol isoamílico y Chelex® 100. La temperatura de hibridización y las concentraciones de cloruro de magnesio, empleando un diseño factorial incompleto 6x7, permitieron establecer un límite de detección de hasta 10 pg de ADN en cultivos puros de Salmonella typhi. La PCR se basó en la exclusividad de los oligonucleótidos 139-141, los cuales amplificaron una banda de 284 pb para la identificación de género. Los resultados muestran que: (I) la adición de Novobiacina (45 mg/L) o de verde brillante (10 mg/L) como inhibidores de flora acompañante, después de las primeras tres horas del pre-enriquecimiento no selectivo de 6 horas, no influye significativamente en la recuperación de las células bacterianas; (II) obtener biomasa de la primera dilución en base 10 y emplear la técnica de fenol:cloroformo:alcohol isoamílico para la obtención de ADN, se pueden detectar 2 UFC/mL de Salmonella sp. en leche en polvo y que el tiempo de detección se reduce considerablemente...
The traditional methods to identify Salmonella sp. are based on the culture medium use that allows the recovery of the micro organism, isolation in selective media, biochemical and serologic characterization. These methods are tedious, have a low specificity and sensitivity and they generally consume a long time. The main objective of this study was to standardize and to optimize the PCR technique to detect Salmonella sp. in 12 hours, from DNA of pure cultures and from powdered milk samples, intentionally inoculated with 200, 20 and 2 CFU/mL. For the extraction of DNA, two methods were used: phenol:chloroform:isoamyl alcohol and chelex® 100. The optimization of the temperature of hibridización and the concentrations of Magnesium Chloride, using an incomplete factorial desing 6x7 allowed to establish a detection limit of up to 10 pg of DNA from pure cultures of Salmonella typhi. The PCR was based on the specificity of oligonucleotidos the 139-141, that amplified a band of 284 pb for the gender identification. The results show that: (I) the inhibitor addition of accompanying flora like Novobiocin (45 mg/L) or brilliant green (10 mg/L) as inhibitors of accompanying flora, after the first three hours in the nonselective pre-enrichment of 6 hours, does not significantly influence in the recovery of the bacterial cells, (II) when obtaining biomass of the first dilution in base 10 and using the phenol:chloroform:isoamyl alcohol technique for the extraction of DNA; can be detected 2 CFU/mL Salmonella s.p. from powdered milk and that the PCR technique reduces the time of test considerably...
Subject(s)
Diagnosis , Process Optimization , Salmonella , Breast-Milk SubstitutesABSTRACT
A new spectrophotometric method, ion-exchanger colorimetry for measuring iron (Ⅱ) in powdered milk fortified with iron(Ⅱ) has been developed. The method was based on the direct measurement of the resin phase absorbance after the absorption of colored sample complex species. In this method, 1,10-phenanthroline was used as the colour reagent, citric acid-sodium citrate as buffer and citric acid-ammonia as masking agent.The recovery rate of the method was 102%. Coefficient of variation was 5.84%.This method was a sensitive, reliable and simple analytical method for the determination of iron (Ⅱ) in powdered milk fortified with iron (Ⅱ).It was also possible to determine iron(Ⅱ) in powder milk and other food.