Application of ozone for the postharvest treatment of fruits and vegetables.

Fruits and vegetables consumption has risen noticeably during recent decades, leading to a greater frequency of foodborne illnesses associated with fresh produce. Novel industrial applications and improvements in ozone technology together with new regulatory actions worldwide have emerged in recent years, making its use in the food industry easier. This technology has attracted considerable commercial interest, especially because ozone does not leave any residues on the treated produce and it is also accepted by many organic grower organizations. However, discrepancies regarding the efficacy of this technology are often found in the bibliography and further research is still needed. These differences could be attributed to a great variability in the conditions of the research work: method of ozone generation and application, O3 concentration and exposure time to the gas, as well as the way in which produce is packed. In this sense, standardization in the working conditions and in the units to measure ozone concentration will be useful to better understand the mode of action and the effects of ozone on food products. Consequently, it would be possible to improve its potential as a sanitizer in the food industry.

Detection of fusarin C and trichothecenes in Fusarium strains from Spain.

A group of 49 strains of Fusarium sp. isolated from different Spanish samples of cereals and mixed feedstuffs were screened for their ability to produce trichothecenes like T-2 toxin (T-2), HT-2 toxin (HT-2), diacetoxyscirpenol (DAS) and deoxynivalenol (DN), as well as other mycotoxin produced by Fusarium named fusarin C. The production of these mycotoxins was analyzed by means of spectrophotometry, thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and gas chromatography (GC). Results showed that from 19 Fusarium strains in which cultures trichothecene production was detected, 15 were HT-2 producers, 9 T-2 producers, 14 DAS producers and 10 DN producers. On the other hand, from 28 Fusarium strains in which cultures fusarin C production was detected, 22 were low fusarin C producers (ranged from 0.04 to 1 microgram/l ICI medium), 5 Fusarium strains were intermediate-level producers (ranged from 1 to 10 micrograms/l ICI medium) and one Fusarium strain produced 240 micrograms/l ICI medium. The identified Fusarium strains that produced trichothecenes and fusarin C were F. moniliforme and F. oxysporum.

Incidence and distribution of Fusarium species associated with feeds and seeds from Spain.

Samples of seeds and feeds (corn-based and mixed) were collected during surveys in 1991-92 and 1992-93 from two regions of Spain, one in northern Spain where the annual rainfall is over 900 mm, and the other in southeastern Spain where the annual rainfall is about 400 mm. The level of Fusarium contamination was determined in the 657 samples analysed, and results were analysed statistically to assess the effects of type of sample and meteorological conditions on Fusarium proliferation. The predominant Fusarium species was Fusarium moniliforme, which represented 92.2% of the total Fusarium strains isolated. Other species isolated were Fusarium oxysporum (5.9%), F. oxysporum var. redolens (0.6%), Fusarium poae (0.6%) and Fusarium sporotrichioides (0.6%).