Abstract
Objectives - The three objectives of this study are: first, to investigate how Cronobacter spp. are distributed
throughout a recalled and a normal batch of powdered infant formula (PIF); second, to investigate
the occurrence of conglomerations of Cronobacter spp. cells, since conglomerations of cells with
high concentrations may impact on risk assessment and public health; and third, to investigate the
performance of typical sampling plans.
Results - In the recalled batch the concentrations Cronobacter spp. versus the filling time was
assessed by 415 samples of 333 g using the MPN technique. In 58 % of the samples,
concentrations were below the detection limit of -2.52 log CFU/g. However, specifically within
three time intervals MPN concentrations were estimated varying between -2.52 and 0.66 log
CFU/g. In addition 2290 samples of 1 g were investigated by plating, and 8 were found to contain
Cronobacter spp. above the detection limit of 0.52 log CFU/g. These samples were originating
from packages filled at the time interval with also the highest MPN concentrations. The two largest
conglomerations were 123 and 560 cells in 1 g of PIF. In 99% of the samples from the normal
batch, concentrations were below the detection limit.
Various sampling plans were evaluated for the contamination data from the recalled batch.
Keeping the total sample weight constant at 300 g and increasing the number of random samples
from 1 to 300, increased the probability of detection from 0.38 till 1.00.
Conclusions - Cronobacter spp. was distributed heterogeneously within a recalled batch of PIF with parts of the
batch with no detectable contamination, and parts of the batch with concentrations up to 2.75 log
CFU/g.
The presence of conglomerations of Cronobacter spp. cells occurred with a low frequency.
Taking more and smaller samples, keeping the total sampling weight constant, considerably
improved the performance of the sampling plans to detect such a type of contaminated batch.
Original language | English |
---|---|
Title of host publication | Conference Proceedings 7th International Conference on Predictive Modelling of Food Quality and Safety, Dublin, Ireland, 12 - 15 September, 2011 |
Editors | E. Cummins, J.M. Frías, V.P. Valdramidis |
Place of Publication | Teagasc, Dublin, Ireland |
Publisher | UCD, DIT |
Pages | 86-89 |
ISBN (Print) | 9781900454469 |
Publication status | Published - 2011 |
Event | 7th International Conference on Predictive Modelling of Food Quality and Safety, Dublin, Ireland - Duration: 12 Sept 2011 → 15 Sept 2011 |
Conference/symposium
Conference/symposium | 7th International Conference on Predictive Modelling of Food Quality and Safety, Dublin, Ireland |
---|---|
Period | 12/09/11 → 15/09/11 |