Mycotoxin, fruit patulin

Mycotoxins are toxic secondary metabolites produced by fungi growing within or on foods. They can be a serious threat to human and animal health (Nagler el al., 2001). Table 11.4 details mycotoxins associated with soft drinks and fruit juice manufacture and raw materials. Patulin is the most common mycotoxin associated with fruit juice, particular ly apple juice (Pitt Hocking, 1997). It commonly occurs if juice is produced from stored apples. Mould growth in infected apples increases with time, raising levels of patulin. The use of windfall apples for juice is also a factor. Avoidance of windfall apples, filtration of juice and pressing quickly after harvest are all methods to reduce the incidence of patulin in juice. Patulin can be destroyed by fermentation to cider or by the addition of ascorbic acid (Marth, 1992). Within Europe, the European Union has set a limit of 50 ig/kg for patulin in both apple juice and cider. A recent survey of apple products in Chile found that 28% of samples of juice and concentrate exceeded this limit (Canas Aranda, 1996). 

Mycotoxin contamination of foods may cause considerable economic losses. On a global perspective, aflatoxins in tree nuts, dry fruits, and spices, Fusarium toxins in cereals (particularly maize, wheat, and barley), and ochratoxin A in cereals and coffee are of major importance (Bhat and Vasanthi, 1999). Regional problems also may arise from mycotoxins in fruits such as patulin in apples, ochratoxin A in grapes and dried vine fruits, or aflatoxins in different dried fruits. 

In terms of product safety, diffusion of mycotoxins in infected fruits and possible health risks associated with the processing or consumption of the remainder of an infected fruit after removal of visibly rotted tissue is of interest. Laidou et al. (2001) investigated the diffusion of patulin in the flesh of pears inoculated with four pathogens, P. expansum, A. flavus, Stemphy-lium vesicarium, and A. alternata. P. expansum and A. flavus penetrated more rapidly into the flesh than S. vesicarium and A. alternata because of the... 

Apples and pears are the fruits most frequently contaminated with patulin. As a consequence, most scientific publications on mycotoxin contamination of fruit juices deal with the occurrence of patulin in apple juice. Table V shows the most important surveys on the occurrence of patulin in apple juice for the last five years. The frequency of contamination ranged from 13 to 81%. Apart from one Turkish study with a mean of 140 pg/L (Yurdun et al., 2001), mean patulin concentrations were rather low and usually below 50 pg/ L. The highest patulin concentration was 733 pg/L, but concentrations up to 1150 pg/kg have occasionally been reported for commercially available apple juice (Beretta et al., 2000). 

Certain groups of a population may be at risk for elevated exposure to mycotoxins if certain fruit products significantly contribute or even dominate the daily diet. This has especially been shown for infants and young children for patulin in apple juice and ochratoxin A in dried vine fruits. Furthermore, wine and cider may significantly contribute to ochratoxin A intake of adults. As a consequence, maximum mycotoxin concentrations for certain fruit products have been established in several countries. 

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