**1. Introduction**

Mycotoxins are compounds produced by naturally occurring fungi having toxic nature for animals and humans [1–3]. It has been considered that approximately 25% of total world food crops annually are contaminated with mycotoxins [4]. Patulin mycotoxin (a polyketide lactone 4-hydroxy-4H-furo (3,2c) pyran-2 (6H)-one; Figure 1) [5,6] belongs to a class of toxic compound with low molecular weight (154.121 g/mol) [7,8]. The molecular formula of patulin (PAT) is C7H6O4; it is stable in aqueous media at 105–125 ◦C with melting point of 110 ◦C. It is a colorless and crystalline compound [9,10]. PAT is often associated with fruits, juices, and derived products, including foods intended for young children, because of the contamination with fungal species such as *Penicillium expansum*, *Aspergillus clavatus*, and *Byssochlamys nivea* [11]. These patulin-producing fungi attack susceptible products during growth, harvest, storage, or food processing. Among different fungi species, *Penicillium expansum*, which is commonly present in many varieties of fruits, is the major producer of PAT [12–14]. Patulin has been primarily associated with apple and apple-based products. However, the toxin may also contaminate other fruits, moldy feed, rotten vegetables, and wheat straw residue. It has been suggested that cold regions may become liable to temperate problems concerning patulin in foodstuffs due to climate change [15].

**Figure 1.** Molecular structure of patulin.

Due to contamination of food and feed at all phases of processing, storage, transportation, and sale, PAT has a critical effect in agriculture zone and food industry. PAT mycotoxin causes health hazards after ingestion of contaminated fruits and derived products. PAT toxicity relates to deleterious formation of adducts with sulfhydryl groups, producing acute and chronic toxicity problems in animals and humans [16]. Exposure to this mycotoxin is associated with immunological, neurological, and gastrointestinal outcomes such as distension, ulceration, and hemorrhage [17,18]. Body organs affected by PAT include kidney, liver, intestine, spleen, and stomach. PAT toxicity in mammalian cells and animals includes genotoxicity, teratogenicity, embryotoxicity, and immunotoxicity [19,20]. According to the International Agency for Research on Cancer (IARC), PAT is classified in the group 3 as "not classifiable as to its carcinogenicity to humans" [20].

The adverse health effects of PAT have led to the establishment of safe levels of PAT in foodstuffs. The Codex Alimentarius established the maximum level of PAT in fruits and juices at 50 μg/kg [21]. According to Commission Regulation (EC) No. 1881/2006, the European Union (EU) fixed maximum levels of PAT in fruit juices (50 μg/kg), solid apple products (25 μg/kg), and foods intended for infants and young children (10 μg/kg) [22]. Countries such as China, USA, and Canada have also established maximum levels for PAT in foods, primarily in apple-based products, in the range between 25 and 50 μg/kg [23–25]. Furthermore, the Joint Expert Committee for Food Additives has established a provisional maximum tolerable daily intake of 0.4 μg/kg body weight [26].

It is well established that the main sources of PAT in human diet are apples and apple-derived products, so the majority of reported studies concern patulin determination in apple-based foodstuffs [27,28]. However, monitoring of PAT in other fruits and fruit-derived products should not be neglected. A previous study carried out in Pakistan on various fruits, juices and smoothies showed the presence of PAT in more than 50% of samples with a mean concentration of 182 μg/kg (Iqbal et al., 2018) [29]. However, mango and orange fruits, and their derived products were not included in the survey.

In view of the above details, the present research has focused on exploring the current occurrence of PAT in mango and orange fruits, fruit juices and derived products, and to compare the levels of PAT with maximum regulatory levels.
