Carolina Rodrigues da Fonseca

Storage of refrigerated raw goat milk affecting the quality of whole milk powder.

The aim of this study was to evaluate the influence of the growth of lipolytic bacteria in raw goat milk stored under refrigeration for different periods on quality parameters of goat milk powder during its shelf life. Fresh goat milk (100L) was collected after milking, divided into 3 identical fractions, and stored at 4°C for 1, 3, and 5d. On d 1, 3, and 5, one sample (1L) was collected and used for microbiological and chemical analysis, and the remaining fraction (almost 30L) was spray dried and stored at 25°C. Milk powder was submitted to microbiological, chemical, and sensory analysis immediately after production, and on d 60, 120, and 180. Lipolytic psychrotrophic counts and total free fatty acid content did not increase in raw milk during storage. However, peroxide value, caprylic and capric acid concentrations, and total free fatty acid content of milk powder increased during 180d of storage, with higher levels found in milk powder manufactured with raw milk stored for 5d. Capric odor and rancid flavors increased in milk powder during storage, regardless the of storage of raw milk for 1, 3, or 5d. Heat treatments used during powder processing destroyed lipolytic psychrotrophic bacteria, but did not prevent lipolysis in milk powder. Results of this trial indicate that the storage of raw goat milk at 4°C should not exceed 3d to preserve the quality of goat milk powder during its shelf life of 180d.

Incidence of Aflatoxins in Oil Seeds and Possible Transfer to Oil: A Review

Aflatoxins are secondary metabolites produced by fungi of the genus Aspergillus, predominantly by A. flavus,A. parasiticus and A. nomius, which occur naturally in foodstuffs, leading to a wide variety of toxic effects in vertebrates, including humans. Contamination of food products with aflatoxigenic fungi may occur during production, harvesting, processing, transportation and storage. Human exposure to mycotoxins occurs primarily through the ingestion of contaminated food, including corn, peanuts, cotton seeds, as well as other oily seeds, such as sunflower and coconut. The procedures used for the extraction and refining of edible vegetable oils can be effective in reducing aflatoxins, varying with the type of oil and method of oil refining. However, numerous studies have reported high incidence of aflatoxins contamination in edible oils worldwide. The production of oils from oilseeds requires the following steps: storage of grains, preparation, extraction of crude oil and refine (degumming, deacidification, bleaching, deodorization, among others). Some of these steps may be harsh and lead to inactivation or elimination of important compounds, such as vitamins, antioxidants and enzymes, although the effect on undesirable compounds like aflatoxins varies markedly among methods. This review presents the current data on the contamination of aflatoxigenic fungi and incidence of aflatoxins in raw oilseed as well as derived products, the main technological approaches for the oil production, and discusses the potential transfer of aflatoxins from oilseeds into the final oil product through the process.

Efficiency of a cleaning protocol for the removal of enterotoxigenic Staphylococcus aureus strains in dairy plants

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.

Qualidade do leite de cabra in natura e do produto pasteurizado armazenados por diferentes períodos

QUALITY OF IN NATURA GOAT MILK AND PASTEURIZED PRODUCT STORED FOR DIFFERENT PERIODS. Different periods (0, 3 and 6 days) and 2 temperatures (4 °C and 10 °C) of raw goat’s milk storage and its impact on pasteurized product quality and shelf life were evaluated. In the described periods, slow pasteurization (65 °C/30 min) was carried out and the pasteurized product was stored at 10 °C for 6 days. Raw milk samples were characterized after milk handling and after 3 and 6 days of storage. Pasteurized milk was evaluated immediately after heat treatment and after 3 and 6 days of storage at 10 °C. The counting of mesophiles, total, lipolytic and proteolytic psichotrophic bacteria, total and fecal coliforms, acidity, fat and free fatty acid (FFA) contents were determined. The microorganisms’ populations had a higher growth at 10 °C than 4 °C. Acidity remained in acceptable levels during storage at 4 °C for 6 days, but not at 10 °C. There was a significant decrease (p < 0.05) in raw milk fat content during storage in both temperatures and a gradual increase of free fatty acids (FFA). Pasteurization was efficient in the reduction of bacteria populations and the lipolytic and proteolytic psichrotrophic microorganisms were non-detectable after heat treatment. However, alterations during raw milk storage affected physical-chemical characteristics of pasteurized milk. During storage, values of pasteurized milk acidity and fat content remained stable, while the amount of FFA increased significantly. It was concluded that raw goat’s milk can be stored for up to 3 days at 4 °C before heat treatment. This condition promotes 6 days of shelf-life after pasteurization. In addition, 10 °C is not a suitable