Contamination profile for staphylococci and its enterotoxins and monitorization of the conditions of hygiene in a 'coalho' cheese production line

This research aimed to evaluate the contamination by staphylococci and its enterotoxins as well as to monitor the Conditions of hygiene from a coalho cheese production like, using ATP bioluminescence assay. Staphylococcus sp. population varied from < ICFU mL(-1), in pasteurized milk to 1.5 x 10(7)CFU mL(-1) in raw milk, whereas coagulase-positive staphylococci count ranged from < ICFU mL(-1), in pasteurized milk to 5.0 x 10(6)CFU mL(-1) in raw milk. Coagulase-positive staphylococci were detected in 100% (25/25) of the row milk samples and in 8% (2/25) of cheese samples. Twelve Staphylococcus species were identified within the selected 68 isolates, being nine negative and three positive for coagulase. Raw milk samples showed a high rate of coagulase-positive, being S. aureus the most common, whereas other product samples and equipment sulfates, pieces of furniture, utensils and manipulator gloves samples presented a high frequency of coagulase-negative and low frequency of coagulase-positive. Staphylococcal enterotoxin was detected in 20% of the raw milk samples and therefore in pasteurized milk, curd and cheese. ATP measurement permitted to assess the effectiveness. of the surfaces cleaning, being considered adequate in 62.1% (36/95), "alert state" in 23.2% (22/95) and inadequate in 14.7% (14/95) of surfaces evaluated. Detection of staphylococci species with enterotoxigenic potential as well as enterotoxin presence reveal dissemination of contamination at the "coalho" Cheese production title, possibly due inappropriate Good Manufacturing Practices (GMP) from the initial milking step until the final cheese production.3851431143

Solid fat content determination: Comparison between pNMR and DSC techniques

Differential Scanning Calorimetry (DSC) has been one of the most popular thermal analysis techniques during the last two decades. The present work shows the utilization of DSC on the determination of solid fat content in fats. Solid fat content values were calculated through the partial areas of DSC heating curves. In a comparison with pulse NMR values, DSC values were generally higher than the pNMR ones. Differences between samples and the techniques themselves seems to be responsible for this fact. DSC is a fast technique on solid fat content, characteristic temperatures and phase transitions enthalpies determinations besides giving a characteristic curve of each sample.46633734

Determination of melting point of vegetable oils and fats by differential scanning calorimetry (DSC) technique

Melting paint of fats is used to characterize oils and fats and is related to their physical properties, such as hardness and thermal behaviour. The present work shows the utilization of DSC technique on the determination of melting point of fats. In a comparison with softening point (AOCS method Cc 3-25), DSC values were higher than those obtained by BOGS method. It has occurred due to the fact that values obtained by DSC technique were taken when the fat had melted completely. DSC was also useful for determining melting point of liquid oils, such as soybean and-cottonseed ones.501162

Characterization of hydrogenated fats for margarine manufacturing purposes

Eight samples of hydrogenated vegetable fats were characterized by their fatty acid composition, trans isomers content and thermal behaviour, using gas chromatography (GC), infrared spectroscopy (IR), pulsed Nuclear Magnetic Resonance (pNMR) and Differential Scanning Calorimetry (DSC) techniques, respectively. Fatty acid composition showed some variations in relation to the unsaturated fatty acids. Trans isomer content, values varied from 22.8% to 35.6%. Solid fat content values were measured using AOCS and IUPAC methods, which differ in the tempering procedures. Values obtained by IUPAC method were higher than the AOCS ones, only at lower temperatures (10 and 21,1 degrees C). Samples were divided into three groups according to their solids profile: superior (C/E/G/H) intermediate (F) and inferior (A/B/D). Melting and crystallization curves were obtained by Differential Scanning Calorimetry. Melting enthalpies ranged from 51.3 to 76.5 J.g(-1) and crystallization enthalpies varied from -34.2 to -18.9 J.g(-1) Characteristic temperatures showed little differences between the samples and each of them showed a characteristic DSC curve. All samples showed a great melting range as expected for hydrogenated fats used for margarines manufacture.4911