Use of a multivariate approach to assess the incidence of Alicyclobacillus spp. in concentrate fruit juices marketed in Argentina: results of a 14-year survey.

The purpose of this study was to determine the incidence of Alicyclobacillus spp. in fruit/vegetable juices (concentrated pulps and clarified and non-clarified juices) marketed in Argentina between 1996 and 2009. The presence of Alicyclobacillus was determined in a total of 8556 samples of fruit and vegetable juices (apple, pear, grape, peach, blend of juices, tangerine, pineapple, orange, mango, plum, guava, apricot, lemon, banana, kiwi, carrot, strawberry, grapefruit, and beetroot) collected in seven Argentinean provinces. Multiple factor analysis (MFA) was carried out on a data matrix that contained the percentage of positive samples, type of juice, raw material and production year. Except for kiwi and orange, Alicyclobacillus was found in juices from all the evaluated raw materials. The highest percentage of positive samples was found for beetroot, strawberry, banana, peach, mango, carrot and plum juices. The percentage of positive samples for these juices ranged from 100% to 24%. Furthermore, the application of multivariate techniques provided an insight on the relationship between the incidence of Alicyclobacillus and production variables. This approach enabled the identification of the most relevant variables that increased the percentage of positive samples among the juices, which could help in developing strategies to avoid the incidence of this bacterium. By means of hierarchical cluster analysis seven groups (clusters) of juices which showed different percentages of positive samples for Alicyclobacillus spp. were identified. This analysis showed that pineapple, peach, strawberry, mango and beetroot juices had higher rates of positivity for Alicyclobacillus than the rest of the evaluated juices. MFA analysis also showed that some clear relationships could be highlighted between the percentage of samples positive for Alicyclobacillus and five types of fruit juices (strawberry, beetroot, grapefruit, pineapple and mango). It was observed that a large proportion of juices produced in 2000, 2005 and 2008 were located in clusters with higher incidence of Alicyclobacillus spp., whereas a larger proportion of clarified concentrate juice and concentrate pulp samples showed higher probability of incidence of Alicyclobacillus in these products. Data presented in this study brings a contribution to the ecology of Alicyclobacillus in fruit/vegetable juices marketed in Argentina. This information would be useful to enhance the microbiological stability of fruit juices regarding the presence of Alicyclobacillus spp.