The rheological and microstructural characteristics of a range of processed cheese analogues manufactured with different moisture contents and mixing speeds were investigated using frequency sweep, creep tests, compression to fracture and confocal microscopy. Cheeses with lower moisture content showed significantly higher values of G' and G″. Young's modulus, peak stress and work in compression as well as lower values for creep compliance. Moisture content played a more significant role than mixing speed in yielding textural differences in the products. The confocal micrographs showed that the fat droplet size decreased with decreasing moisture content, but little effect of mixing speed on the droplet size was detected. The effect of mixing speed was marginal or nonexistent, possibly due to the narrow range investigated.

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Aims:  To identify the types of micro‐organisms involved in the formation of biofilms on dairy ultrafiltration and reverse osmosis membranes and investigate factors affecting the attachment of those isolates. Methods and Results:  Micro‐organisms isolated from industrial membranes following standard cleaning were identified using the API culture identification system. Thirteen different isolates representing eight genera were isolated and their ability to attach to surfaces was compared using a microtitre plate assay. Three Klebsiella strains attached best, while mixed strains of Pseudomonas and Klebsiella attached better than individual strains. Whey enhanced the attachment of the isolates. The micro‐organisms were characterized according to cell surface hydrophobicity using the microbial adhesion to hydrocarbon (MATH) test, and cell surface charge by measuring the zeta potential. These cell surface characteristics did not show a clear relationship with the attachment of our strains. Conclusions:  A variety of different micro‐organisms is associated with dairy ultrafiltration and reverse osmosis membranes after cleaning, suggesting several possible sources of contamination. The cleaning of these membranes may be inadequate. The attachment of the different isolates is highly variable and enhanced in the presence of whey. Significance and Impact of the Study:  Knowledge of persistent microflora colonizing dairy membrane systems will help develop strategies to mitigate biofilm development in this environment, improving hygiene in membrane processing plants.