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Crescenza cheese was prepared from milk that was naturally contaminated with aflatoxin M1 (AFM1). Three milk batches were processed at AFM1 levels of <5, 128 and 257 ng kg-1. AFM1 analysis was carried out using an immunoenzymatic technique (ELISA) and HPLC. After clotting, AFM1 was analysed on both curd and whey fractions. The Enrichment Factor of the toxin in the curd over that in the milk was on average 2.56±0.13, while about 50% of the toxin remained in the whey. Cheese samples were analysed for AFM1 content during the 15-day storage time. The AFM1 concentration decreased during the first 5 days and then remained constant. [ABSTRACT FROM AUTHOR]

FT-IR spectroscopy was used to analyse 112 samples of "Provola" cheese, coated with biodegradable wax or paraffin, at 90 and 120 days of shelf-life, in order to verify the discriminating power of this spectroscopic technique. The influence of the two different kinds of wax was also studied. Spectral data were processed using Mean Centre algorithm and transformed into second derivative using the Savitzky-Golay algorithm. Principal Component Analysis was applied to optimise the information given by the spectral data sets. FT-IR spectroscopy was able to classify samples on the basis of shelf-life and to detect the differences in the lipolytic trend due to the nature of the wax used. [ABSTRACT FROM AUTHOR]

Investigates how vacuum infusion (VI) treatment before fruit pasteurization could improve the texture of pear pieces and maintain the texture after their addition to the yoghurt. Description of the VI process; Common technological problems to dairy production process; Information on cryostabilization; Comparison of the yoghurt made using VI fruits with the yoghurt made using the same pear pieces which are not VI treated.

Aflatoxin M1 (AFM1) is a toxic undesirable compound in milk. AFM1 affinity for caseins causes a concentration effect during milk process for dairy transformation. In spite of this, no official method of analysis, nor maximum tolerance level for aflatoxin M1 in cheese have been established. Thus, the aim of this work was to test the suitability of different HPLC methods for the AFM1 quantification in soft cheese samples at three different contamination levels (low, medium and high, at respectively nearly 30, 100 and 250 ng/kg). Nine participants were selected among Italian laboratories accredited by the Italian accreditation body (ACCREDIA) for HPLC toxin analysis. They were asked to analyze samples applying the method routinely used. The different applied methods were compared, and precision and accuracy parameters were evaluated. The main differences among HPLC procedures were registered at the level of extraction step. The use of an enzymatic digestion for the extraction of the toxin from cheese seemed to be particularly advantageous and the use of immunoaffinity columns seemed to be determinant for the improvement of sensitivity at low contamination levels. In general, the applied methods well discriminated the 3 levels of contamination, even though they performed better at the medium and high concentration levels (100 and 250 ng/kg) than at the low one (30 ng/kg). In fact relative standard deviation for reproducibility at low level was higher (60.1%) than the same value at medium and high levels (22.8% and 28.9%, respectively)., (Copyright © 2011 Elsevier B.V. All rights reserved.)