Factors affecting penicillium roquefortii (penicillium glaucum) in internally mould ripened cheeses: implications for pre-packed blue cheeses

摘要

The amount and vivid colour of blue veins of internally mould ripened cheeses are desirable quality characteristics. It is therefore important that there is a sufficient amount of veining and that it maintains its\udblue appearance to be appealing to consumers therefore leading to maximised sales potential and profit for\udthe manufacturing company. Optimum in vitro growth mimicking the conditions typically found in prepacked\udblue cheeses, and using lactose as the sole carbon source, was facilitated by a gas mixture of 5%\udoxygen ⁄0% carbon dioxide ⁄ balance nitrogen). The work undertaken in this study determined that the\udfactors for optimum in vitro growth of Penicillium roquefortii (strain PRB6) were: a temperature of\ud20 ± 1 �C, pH of 6.0 ± 0.1, and a relative humidity of 70 ± 0.1%. Further in vitro studies have also shown\udthat the increasing ‘in-pack’ carbon dioxide concentration not only depresses the growth of P. roquefortii but\udalso affects immature conidiospore pigmentation (no effect has been seen on mature conidiospore\udpigmentation). The implications of this study suggest that the majority of pre-packed internally mould\udripened blue cheeses on sale in supermarkets are packaged in inappropriate materials. For some cheeses (e.g.\udthe Roquefort-type cheeses) this is not an issue since these are packed in a much more mature state and some\udloss of veining colour is not appreciably noticeable.