In this review paper, several aspects of fruit juice microbiology, from past to future perspectives, are considered. An overview of the most relevant outbreaks involving foodborne pathogens and spoilage microorganisms associated with fruit juices is provided. One of the sections provides data on the sources of fruit juice contamination, followed by perspectives on preservation methods. Furthermore, considerations on the role of international guidelines about exotic fruit juices in respect to public health, and of the microbiological status of fruit juices used as food/beverage ingredients are discussed. Issues and challenges highlight how the microbiology of fruit juices has evolved over the years, when aspects of stability or microbiological safety are under consideration.

a b s t r a c tThis article is a review about the effects of each of the processing stages of pasteurized apple juice on the increase, prevalence or reduction of patulin (PAT) levels in the final product. Recommendations are included for the control and reduction of the incidence of the moulds that produce it and the mycotoxin itself, from the pre-harvest to the final manufacturing stages of apple juice, studies required for a better understanding of the behaviour of this mycotoxin during processing also being indicated. Although the initial stages of the juice manufacturing process (washing, selection and trimming) are highly efficient in reducing the levels of PAT, control of the mycotoxin should always be focused on the production stages of the process that guarantee the inhibition of its production (pre-harvest, harvest and post-harvest).

Aims:  To determine thermal resistance, the effect of pasteurization temperature variations (c. 2°C) in a continuous system in the number of decimal reductions (n) of a Byssochlamys strain in clarified apple juice (CAJ). Methods and Results:  Thermal destruction kinetics of Byssochlamys fulva IOC 4518 in thermal death tubes were determined at 85°, 90°, 92° and 95°C by using Weibull distribution frequency model. Three processes with different heating and holding temperatures (A: 94°, 92°C; B: 95°, 93°C; C: 96°, 94°C, respectively) were performed in a continuous system. Process time was 30 s. δ (time of first decimal reduction) values were: 42·98, 8·10, 3·62 and 1·81 min. Variable n ranged from 0·16 to >4·78 for process B (equivalent to industrial). Variable n (0·95–2·66 log CFU ml−1) were obtained in CAJ bottles processed under condition B, while process A resulted in total heat‐resistant mould (HRM) survival and process C in total HRM destruction. Conclusions:  This study demonstrates that small variations in temperature during the CAJ pasteurization could result in elimination or survival of HRM due to its nonlogarithmic behaviour. Significance and Impact of the Study:  This was the first study to use Weibull frequency method to model inactivation of HRM in fruit juices. Temperature variations could culminate in the presence of HRM in pasteurized juices even when low counts (<10 spores per 100 ml) were present in the raw materials.

No abstract

This research evaluated the inactivation of a heat-resistant Aspergillus niger conidia in mango nectar by high-pressure homogenization (HPH) combined with heat shock. A. niger were inoculated in mango nectar (10(6) conidia mL(-1)) and subjected to HPH (300 to 100 MPa) and heat shock (80 degrees C for 5 to 20 min) before or after HPH. Processes were evaluated according to number of decimal reductions reached by each isolated or combined process. Scanning electron microscopy was performed to observe conidia wall after pressure treatment. Pressures below 150 MPa did not inactivate A. niger while pressures of 200 and 300 MPa resulted in 2 and more than 6 log reductions, respectively. D(80 degrees C) of A. niger was determined as 5.03 min. A heat shock of 80 degrees C/15 min, reaching 3 decimal conidia reductions, was applied before or after a 200 MPa pressure treatment to improve the decimal reduction to 5 log cycles. Results indicated that HPH inactivated A. niger in mango nectar at 300 MPa (>6.24 log cycles) and that, with pressure (200 MPa) combined with post heat shock, it was possible to obtain the same decimal reduction, showing a synergistic effect. On the other hand, pre heat shock associated with HPH resulted in an additive effect. The observation of A. niger conidia treated by HPH at 100 and 200 MPa by scanning electron microscopy indicated that HPH promoted intense cell wall damage, which can sensitize the conidia to post heat shock and possibly explain the synergistic effect observed. Practical Application: The results obtained in this paper are relevant to elucidate the mechanism of conidia inactivation in order to develop the application of HPH as an alternative pasteurization process for the fruit nectar industry.