Pilar R. Massaguer

Influence of package, type of apple juice and temperature on the production of patulin by Byssochlamys nivea and Byssochlamys fulva.

Although the production of patulin in apple fruits is mainly by Penicillium expansum, there is no information on the ability of heat resistant moulds that may survive pasteurization to produce this mycotoxin in juice packages during storage and distribution. In this study, the production of patulin by Byssochlamys spp (Byssochlamys nivea FRR 4421, B. nivea ATCC 24008 and Byssochlamys fulva IOC 4518) in cloudy and clarified apple juices packaged in laminated paperboard packages or in polyethylene terephthalate bottles (PET) and stored at both 21 degrees C and 30 degrees C, was investigated. The three Byssochlamys strains were able to produce patulin in both cloudy and clarified apple juices. Overall, the lower the storage temperature, the lower the patulin levels and mycelium dry weight in the apple juices (p<0.05). The greatest variations in pH and degrees Brix were observed in the juices from which the greatest mycelium dry weights were recovered. The maximum levels of patulin recovered from the juices were ca. 150 microg/kg at 21 degrees C and 220 microg/kg at 30 degrees C. HPLC-UV, HPCL-DAD and mass spectrometry analyses confirmed the ability of B. fulva IOC 4518 to produce patulin. Due to the heat resistance of B. nivea and B. fulva and their ability to produce patulin either in PET bottles or in laminated paperboard packages, the control of contamination and the incidence of these fungi should be a matter of concern for food safety. Control measures taken by juice industries must also focus on controlling the ascospores of heat resistant moulds.

Heat resistance and the effects of continuous pasteurization on the inactivation of Byssochlamys fulva ascospores in clarified apple juice.

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).

Inactivation of Aspergillus niger in mango nectar by high-pressure homogenization combined with heat shock.

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.

Influence of Different Filling, Cooling, and Storage Conditions on the Growth of Alicyclobacillus acidoterrestris CRA7152 in Orange Juice

ABSTRACT The prevention of spoilage by Alicyclobacillus acidoterrestris is a current challenge for fruit juice and beverage industries worldwide due to the bacteriums acidothermophilic growth capability, heat resistance, and spoilage potential. This study examined the effect of storage temperature on A. acidoterrestris growth in hot-filled orange juice. The evolution of the A. acidoterrestris population was monitored under six different storage conditions after pasteurization (at 92°C for 10 s), maintenance at 85°C for 150 s, and cooling with water spray to 35°C in about 30 min and using two inoculum levels: <101 and 101 spores/ml. Final cooling and storage conditions were as follows: treatment 1, 30°C for the bottle cold point and storage at 35°C; treatment 2, 30°C for 48 h and storage at 35°C; treatment 3, 25°C for the bottle cold point and storage at 35°C; treatment 4, 25°C for 48 h and storage at 35°C; treatment 5, storage at 20°C (control); and treatment 6, filling and storage at 25°C. It was found that only in treatment 5 did the population remain inhibited during the 6 months of orange juice shelf life. By examining treatments 1 to 4, it was observed that A. acidoterrestris predicted growth parameters were significantly influenced (P < 0.05) either by inoculum level or cooling and storage conditions. The time required to reach a 104 CFU/ml population of A. acidoterrestris was considered to be an adequate parameter to indicate orange juice spoilage by A. acidoterrestris. Therefore, hot-filled orange juice should be stored at or below 20°C to avoid spoilage by this microorganism. This procedure can be considered a safe and inexpensive alternative to other treatments proposed earlier.

Modelling the lag time and growth rate of Aspergillus section Nigri IOC 4573 in mango nectar as a function of temperature and pH

Aims: To assess the behaviour of Aspergillus section Nigri IOC 4573 in mango nectar as affected by temperature and pH.

Influence of the hot-fill water-spray-cooling process after continuous pasteurization on the number of decimal reductions and on Alicyclobacillus acidoterrestris CRA 7152 growth in orange juice stored at 35 °C

In this study, the influence of the hot-fill water-spray-cooling process after continuous pasteurization on the number of decimal reductions (gamma) and growth parameters (lag time; lambda, ratio N(f)/N(o); kappa, maximum growth rate; mu) of Alicyclobacillus acidoterrestris CRA 7152 in orange juice stored at 35 degrees C were investigated. Two different inoculum levels of A. acidoterrestris CRA 7152 (10(2) and 10(3) spores/mL) in orange juice (11(0)Brix, pH 3.7) and a Microthermics UHT-HTST pilot plant were used to simulate industrial conditions. Results have shown that regardless of the inoculum level (10(2) or 10(3) spores/mL), the pasteurization processes were unable to cause even 1 gamma. Predictive modeling using the Baranyi model showed that only kappa and time to reach 10(4)spores/mL (t10(4) - time to juice spoilage) were affected by the spore inoculum used (p<0.05). It has been concluded that A. acidoterrestris was able to survive the hot-fill process and to grow and spoil orange juice in 5-6 days when the final storage temperature was 35 degrees C.

The development of an analytical method for two mycotoxins, patulin and verruculogen, and survey of their presence in commercial tomato pulp

The mycotoxin patulin causes gastroinstestinal distress, neurotoxic and immunotoxic effects in animals. It can be produced by several species of Penicillium, Aspergillus and Byssochlamys and it has been found in fruits, vegetables and cereals. Verruculogen is a toxin produced mainly by Penicillium and Aspergillus spp. and causes severe tremors in affected animals. Tomatoes are especially susceptible to fungi invasion and their products need to be investigated for possible mycotoxin contamination. A method for the determination of patulin and verruculogen in tomato products was developed involving an extraction with ethyl acetate, a cleanup by silica gel column and determination and confirmation by high performance liquid chromatography with diode array detector. The quantification limits of the method, defined as the minimum amount that allowed quantification and confirmation by the DAD detector, were 10 ng/g and 20 ng/g. The average recovery for patulin at five levels of addition (from 20 to 200 ng/g) was 75% and at the single level of 100 ng/g was 90 % .The average recovery for verruculogen at five levels of addition (from 50 to 300 ng/g) was 54% and at the single level of 100 ng/g was 52%. The processing of two tomato plants was followed during 1996, 1997, and 1998. Eighty-four samples of tomato pulp were analyzed for patulin and verruculogen. The toxins were not detected in any of the samples.