Abstract: Patulin is a secondary metabolite of polyketide lactone mainly produced by species of Penicillium, Aspergillus, and Byssochylamys. It was found as a contaminant in many fruits and fruit products, the major sources of contamination are apples and apple products, which are also the most important source of patulin in human diet. Patulin has various acute and chronic effects and others at the cellular level. Today, international organizations (Codex Alimentarius Commission and European Union) and many countries across the world have set maximum levels of patulin content in fruit and fruits products. Among the different genera, the most important patulin producer is P. expansum, it can contaminate a number of fruits and fruit products, and produce mycotoxin patulin. P. expansum distributes very extensively, its strains have been isolated from many countries. As a plant pathogen, P. expansum penetrates fruits typically through wounds or injuries produced during harvest and handling, it can also penetrate through stem end, open calyx tube and lenticels of fruits, and infection sites of other primary fruit pathogens. Overmature or long-stored fruits are more susceptible to P. expansum infection. P. expansum is a psychrophile, its growth is quite strong at 0℃. The biosynthetic pathway of patulin consists of approximately 10 steps. It has been clarified that both of the patulin biosynthetic gene cluster from P. expansum and that from A. clavatus composed of the same 15 genes, but their gene sequences differed greatly. The genotoxic and cytotoxic properties of patulin are due to its high reactivity to cellular nucleophiles. Patulin is believed to exert its toxic, chromosome-damaging, and mutagenic activity mainly by covalent binding to cellular nucleophiles, in particular to the thiol groups of proteins and glutathione (GSH). In the major reaction pathways, up to three molecules of glutathione can bind to one molecule patulin. To control the contamination of patulin and the growth of moulds producing it, pre-harvest measures, post-harvest treatments, and storage conditions deserve special attention. The use of chemical fungicides is an important strategy, but the overuse of fungicides will lead to the emergence of fungicide-resistant strains. Because their way of action reduces the risk of resistant population emergence, “low risk fungicides” are more suitable and efficient. Using biocontrol agents are alternative or complementary treatments that permit to decrease fungicide doses or even avoid the use of chemicals. Some stages of manufacturing process (such as washing, sorting and trimming) are highly efficient in reducing the levels of patulin in fruit products. Liquid-liquid extraction (LLE) and solid-phase extraction (SPE) are classical methods to extract patulin in fruits and fruit products. However, LLE is expensive, time consuming, and unsuitable for the treatment of solid sample. In the last years, some other extraction measures have been studied and developed, including DLLME, IL-DLLME, BS-DLLME, salting out-VALLME, MSPD, and QuEChERS. LC-UV or LC-DAD procedure is routinely used for quantitative determination of patulin, and methods to confirm the presence of patulin usually include more specific detection techniques such as LC-MS/MS and GC-MS/MS. PCR method is a fast and specific method of early detecting the potential patulin producing fungi.

Key words: fruit, fruit product, patulin, contamination, occurrence, control, determination