## 3 Patulin Control Methods
### Filtering and adsorption  
A number of studies have been devoted to the removal of patulin from juice through the use of adsorption filters, columns, and agitation treatments using carbon-based material. Agitation with 20 mg/mL activated charcoal followed filtration through a 40-or 60-mesh charcoal column reduced a 30 \(\mu\)g/mL patulin to below detectable levels. Further, use of 5 mg/mL charcoal in agitation was able to reduce patulin to below detectable levels in naturally contaminated cider. However, colour loss was markedly present in this resulting juice [233]. In a study [PERSON] and [PERSON] [234] added different amounts of activated charcoal viz. 0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3 g/L to naturally contaminated apple juice containing 62.3 mg/mL patulin. Samples were mixed for 0, 5, 10, 20, and 30 min. Three grams/litre activated charcoal was found to be most effective with a time period of 5 min. Clearness of juice increased, colour of juice decreased and small decreases in fumaric acid, pH and Brix (a measure of the dissolved sugar-to-water mass ratio of a solution) were also seen. In another study, ultrafine activated carbon was found to granular quartz producing a composite carbon adsorbent (CCA). Columns with varying amounts of CCA were prepared and 10 \(\mu\)g/mL patulin were filtered through at 1 mL/min. Fifty percent breakthrough values for columns with 1.0, 0.5, and 0.25 g CCA were 137.5, 38.5, and 19.9 \(\mu\)g respectively [235]. In a study designed to compare the effects of different carbon activation methods, steam activated carbons, NORIT SA 4 and NORIT SX 4 removed 80% and 70% respectively, of an initial 1 g/L patulin solution in 12 Brix juice at 55 \({}^{\circ}\)C. Chemically activated carbon NORIT CA 1 removed only 45% of the same solution. This study also showed that increased Brix levels of juice led to decreased patulin removal efficiency, with NORIT SA 4 removing only 20% of patulin from 20 Brix juice. Within this study, patulin removal was independent of juice temperature between 30 and 65 \({}^{\circ}\)C [236]. In another study, patulin binding to activated carbon compounds was shown to be endothermic, with increased temperatures resulting in improved patulin removal [237].  
Despite these initial studies where activated carbon was shown to reduce patulin, little work has been done to optimize carbon for this process. Furthermore, the use of activated carbon poses a substantial cost to the juice industry [236], being both time consuming and expensive [224]. In addition to the cost of the carbon material itself, activated charcoal treatment creates excess waste that must be dealt with ecologically [223]. Also, as mentioned within several of these studies, negative effects on colour, fumaric acid content, pH, and \({}^{\circ}\)Brix have been observed with carbon adsorption. These and other modifications made by carbon absorption treatments can negatively alter the taste perception and quality of the juice [237]. Finally, the use of clays can pose risk due to removal of essential nutrients from juice [238]. Similar analysis with activated carbon compounds has not been performed, but could very likely have the same negative result.