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Figure 5.13 Cryptosporidium Raman spectra. Source: Reproduced from Grow et al. 52 with
the permission of the journal. A window from the SERS spectra of two C. parvum geno-
type 2 strains: (a) A calf isolate from Iowa and (b) an isolate from a foodborne outbreak in
Maine, comparing the fingerprints of recently passaged (- - -) and old (—) samples. Note
that the old samples give similar fingerprints, whereas the recently passaged oocysts
can be readily differentiated, e.g. by the ratios of the peak heights at 1659 cm −1 and in
the 1250-1350 cm −1 range. Background corrected.
5.2.3. Other methods
Multiwavelength UV-vis spectroscopy was presented in one conference
paper showing significant spectral differences between three different
pathogens ( Fig. 5.14 ). 58 Hyperspectral imaging is an emerging technique
that has been applied to foodborne pathogens. 59
5.3. SUMMARY
This chapter has covered a range of optical techniques and reviewed
the position with regard to waterborne pathogens.
First, fluorescence-based detection was discussed. While well-established
as a means of detection, the need for reagents is a problem in terms of cost
and storage, especially for portable applications or those in remote areas.
New fluorescent probes offer greater stability but at an increased price. Fur-
ther details of nanotechnology developments for signal enhancement are
 
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