Residual formaldehyde contents in fresh white cheese in El Salvador: Seasonal changes associated with temperature.

Detection of residual formaldehyde (FA) in dairy products could be explained by direct addition of this preservative to extend the shelf life of raw material or final product at room temperature. FA is not authorized as a preservative by international standards and its addition to dairy products is prohibited due to its potentially harmful effects on consumers. Although the carcinogenicity of FA by oral exposure has not been proven, it is also known it cause histopathological and cytogenic changes in tissues at first contact, so its toxicity by ingestion should not be underestimated. This research determined both residual FA levels in locally produced fresh white cheese and its variation according to the seasons of the year and its association with ambient temperature. None of the FA levels quantified in cheese exceeded the maximum tolerable concentration (2.6 mg/kg) and although average FA contents did not vary significantly with seasonal changes (0.093-0.181 mg/kg), the number of positive cases did, since the highest prevalence occurred in the dry (60.9 %) and transitional dry-rainy (79.7 %) seasons of 2021, which are characterized by having the highest average ambient temperatures (27.5 °C and 28.3 °C, respectively). It was also shown that 79.6 % of the variability of FA-positive samples is explained by changes in the average temperature according to the year´s season. The association between these variables and quantified levels of aldehyde in raw milk sampled at the plant could indicate that FA was used to prevent milk and/or the final product from decomposing due to the effect of high ambient temperature. In addition, residual FA contents decreased in both milk and cheese, depending on added preservative levels, and the time elapsed prior to analysis.

Fatores ambientais e de manejo sobre a composição química do leite em granjas leiteiras do Estado do Paraná, Brasil / Environmental and handling factors on the chemical composition of milk in dairy farms of Paraná State, Brazil

O objetivo do trabalho foi avaliar a influência da composição químicobromatológica da dieta total e os fatores ambientais das estações do ano sobre a composição química do leite. As granjas leiteiras estudadas foram identificadas como Granja 1 (G1) eGranja 2 (G2). Definiram-se como tratamento as quatro estações do ano e os dois sistemas de produção leiteira (G1 e G2). Foram coletadas 34 amostras da dieta total fornecida aosanimais em lactação para a análise da composição químico-bromatológica, e 20 amostras de leite cru diretamente dos tetos dos animais para avaliar a composição química do leite, durante as quatro estações ano. Para as análises estatísticas dos dados, foi empregado ométodo dos quadrados mínimos. Constatou-se que houve diferença (p < 0,05) entre a G1 e a G2 para a produção de leite (kg dia-1), porcentagens de gordura, proteína e níveis de ureia no leite (NUL). No entanto, não houve diferença na porcentagem de lactose e sólidos totaisentre as granjas estudadas. Observou-se que a produção (kg dia-1) e todos os componentes do leite analisados diferiram ao longo das quatro estações do ano. Os resultadosdemonstraram que a composição químico-bromatológica da dieta, as fases de lactação e os fatores ambientais das estações do ano podem causar variações na produção e composição química do leite.

The objective of this research study was to evaluate the influence of total diet chemical composition and environment factors of the different seasons of the year on the chemical composition of milk. The milk farms evaluated were classified as Farm 1 (G1) and Farm 2 (G2). The study defined as treatmentsthe four seasons of the year and the milk production system (G1 and G2). A total of 34 diet samples were collected, fed to lactating animals in order to analyze the chemicalbromatologicalcomposition, and 20 samples of raw milk straight from cows in order toevaluate the chemical composition of milk during the four seasons. For data statistical analyses, the method of least squares was used. There was a difference (p 0.05) in lactose and totalsolids percentage between the studied farms. On the other hand, it was observed that the production (kg day-1) and all analyzed milk components were different (p < 0.05) during the four seasons of the year. The results demonstrate that the total diet chemicalcomposition, lactation phases and environments factors of seasons of the year may cause variation in milk production and chemical composition.

Fatores ambientais e de manejo sobre a composição química do leite em granjas leiteiras do Estado do Paraná, Brasil / Environmental and handling factors on the chemical composition of milk in dairy farms of Paraná State, Brazil

O objetivo do trabalho foi avaliar a influência da composição químicobromatológica da dieta total e os fatores ambientais das estações do ano sobre a composição química do leite. As granjas leiteiras estudadas foram identificadas como Granja 1 (G1) eGranja 2 (G2). Definiram-se como tratamento as quatro estações do ano e os dois sistemas de produção leiteira (G1 e G2). Foram coletadas 34 amostras da dieta total fornecida aosanimais em lactação para a análise da composição químico-bromatológica, e 20 amostras de leite cru diretamente dos tetos dos animais para avaliar a composição química do leite, durante as quatro estações ano. Para as análises estatísticas dos dados, foi empregado ométodo dos quadrados mínimos. Constatou-se que houve diferença (p < 0,05) entre a G1 e a G2 para a produção de leite (kg dia-1), porcentagens de gordura, proteína e níveis de ureia no leite (NUL). No entanto, não houve diferença na porcentagem de lactose e sólidos totaisentre as granjas estudadas. Observou-se que a produção (kg dia-1) e todos os componentes do leite analisados diferiram ao longo das quatro estações do ano. Os resultadosdemonstraram que a composição químico-bromatológica da dieta, as fases de lactação e os fatores ambientais das estações do ano podem causar variações na produção e composição química do leite.(AU)

The objective of this research study was to evaluate the influence of total diet chemical composition and environment factors of the different seasons of the year on the chemical composition of milk. The milk farms evaluated were classified as Farm 1 (G1) and Farm 2 (G2). The study defined as treatmentsthe four seasons of the year and the milk production system (G1 and G2). A total of 34 diet samples were collected, fed to lactating animals in order to analyze the chemicalbromatologicalcomposition, and 20 samples of raw milk straight from cows in order toevaluate the chemical composition of milk during the four seasons. For data statistical analyses, the method of least squares was used. There was a difference (p < 0.05) betweenthe G1 and G2 farms, for milk production (kg day-1), fat, protein and milk urea nitrogen (MUN) percentages. However, no difference was observed (p > 0.05) in lactose and totalsolids percentage between the studied farms. On the other hand, it was observed that the production (kg day-1) and all analyzed milk components were different (p < 0.05) during the four seasons of the year. The results demonstrate that the total diet chemicalcomposition, lactation phases and environments factors of seasons of the year may cause variation in milk production and chemical composition.(AU)