Effect of Long-Term Storage, Heat and High Pressure Processing on Patulin Reduction in Tomato Products

Abstract

In this paper, the effect of long-term storage on patulin reduction in different tomato products (juice, puree, pulp, paste, and ketchup) was assessed, together with the evaluation of patulin heat-resistance and baro-tolerance in tomato juice. For these purposes, different extraction methods for patulin detection in tomato products using an RP-HPLC apparatus were preliminarily assessed. Concerning the effect of long-term storage (up to six months) on patulin, at 25°C a non-linear, progressive reduction of the toxin was observed for all tomato products tested during storage. Tomato paste was the matrix where the most marked decrease was observed, patulin being reduced to undetectable levels just after one month at 25°C. It was followed by tomato puree, where the toxin was reduced to unquantifiable levels after six months at 25°C. Differently, the toxin was always present at detectable levels in tomato pulp, puree, and ketchup where it was respectively reduced by 64%, 81%, and 88% after six months at 25°C. Concerning the effect of thermal treatment and High-Pressure Processing on patulin, the DT value (D95=270 min) calculated for tomato juice was much higher than times usually applied in the industrial practice on nonconcentrated tomato products, and the highest time/pressure combination applicable at an industrial level on tomato juice (600 MPa for 10 min) did not give any decimal reduction to patulin concentration. Since all the strategies applied did not prove sufficient to inactivate patulin in all products considered, tomato products other than pastes could represent a risk for this toxin, in case substantial spoilage by patulin-producing fungi occurred on tomato fruits and an insufficient amount of detoxing substances such as L-ascorbic acid was present in the above-mentioned products.