Biology Reference
In-Depth Information
Arcangeli et al.
1996
; Gianfaldoni et al.
1990
; Priebe et al.
1973
) assessed the
efficacy of some salting and/or marinating technologies on larval inactivation rates,
as well as on the reduction of their pathogenicity. However, results showed a high
variability in parasite responses, which could be due to the degree of development
of the larvae or their encystment status, both of which are related to the modality of
fish infestation, the environmental conditions of the fishing site, the morphological
and immune conditions of the gastroenteric tracts of the parasitized fish
(Panebianco et al.
1999
), and the redox potential of fish celomic cavity (Panebianco
et al.
2000
).
Apart from these causes, a careful knowledge of the variable anisakid larvae
responses to the most common food technologies, such as salting, marinating, or
mild thermal treatments, could be very useful for correctly assessing related food
safety issues and the individuation of effective inactivation treatments. The aims of
this work were to assess the variability of responses of a large number of anisakid
larvae as a function of their length and to determine correlations applicable to
predictive algorithms concerning larval inactivation.
26.2 Materials and Methods
The present study was performed on 1,200 motile anisakid larvae sampled from
eight specimens of
Lepidopus caudatus
in a physiological solution that were
harvested within 8 h of sampling. Ten percent of the larvae were examined
microscopically to determine the genus. Afterward, 600 larvae were subdivided
into three groups (200 larvae for each group) and treated with three different
marinades: group A: 5% citric acid, 5% acetic acid, and 13% NaCl; group B:
5% citric acid, 5% acetic acid, and 10% NaCl; and group C: 2.5% citric acid,
2.5% acetic acid, and 8% NaCl. Larval survival was evaluated by stereomicroscopy
every 3 h for group A, every 6 h for group B, and every 12 h for group C. All groups
were maintained at 30
C during the study to increase the dissociation of organic
acids to enhance their activity against the larvae.
The remaining 600 larvae were subjected to sublethal thermal treatments.
Specifically, 400 larvae were preliminarily tested at 45, 47, 48, and 50
C to assess
the temperature that resulted in 100% inactivation of the larval within an appropri-
ate time interval. Based on this experiment, 200 larvae were treated at 47
C and
were stereomicroscopically observed (devitalization assessment) after 15, 20, 25,
30, and 40 min.
All thermal treatments were performed by immersing larvae in glass test tubes
containing 15 ml of prewarmed physiological solution maintained in a bain-marie
at the appropriate temperatures for treatment. At the end of each treatment, larvae
were quickly transferred into 60 ml of physiological solution precooled to 10
C.
The microscopic assessment of larval inactivation was performed after 1 h at room
temperature in the physiological solution.
