food hygiene & safety 21
Table 1. Pasteurisation of seeds, nuts and raisins.
because maximum levels
were exceeded.
These results were
compiled form facilities
equipped with NAPASOL
pasteurisation installations.
Contamination levels
are reduced below
target values following
pasteurisation guaranteeing
microbiologically safe
products.
This technology is
supplied by NAPASOL AG
a Swiss company specialised
in food safety technologies.
Steam injected in a strong
Note: Microbiological loads of samples from nuts, seeds and raisins, pasteurised in a
vacuum allows condensation
NAPASOL unit to eliminate pathogens and spoilage microorganisms. Before pasteurisation
on the surface of the product
microbial loads are above maximum limits (red), after pasteurisation microbial loads have
rapidly raising temperature
dropped blow target values (green).
and effectively killing the
micro-organisms. A
Pathogenic bacteria such as E Coli and Enterobacteria subsequent vacuum phase removes the moisture by
are identified separately. condensation thus cooling and drying the product.
Processors and packing facilities verify the Exposure to heat and moisture are thus minimised
microbiological levels of the foods they handle through to the benefit of the quality of the product. The
quality control. But sampling programs and laboratory thermal treatment developed by NAPASOL is a
analysis will at best identify some of the contaminated rapid low temperature processes that is effective at
material, but not all, because of the random nature of decontamination without cooking the product.
sampling and the inhomogeneous distribution of the
contaminants.
Risks and consequences
Standards for maximum and target levels of Food poisoning might only trigger gastrointestinal
microbiological contamination are set by industry disorders in healthy individuals but in the young, the
specifications. elderly, and those with weakened immune system it can
Suppliers to the food industry have to meet the be life threatening.
strictest standards to minimise the risk of contaminating Several product recalls have affected the spice
the final product and to guarantee its microbiological industry because consumers were using spices and herbs
safety up to the end of its shelf life. to flavour foods that were not subsequently cooked or
Specifications in effect in most nut and seed not cooked at temperatures sufficiently high to be lethal
processing facilities are indicated in Table 2 below. The for the bacteria.
data shown are based on quality controls of incoming Because spices and herbs have notoriously high
ingredients many of which need to be decontaminated microbial loads irradiation and fumigation are
approved processes for
decontamination. However
consumer resistance to
irradiated products and
environmental concerns
related to fumigation
favours treatment with
more natural steam based
thermal processes such as
the technology developed by
NAPASOL AG.
Currently a massive
product recall is affecting the
US peanut industry because
of salmonella contamination.
In this case the peanuts and
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