Handbook of Herbs and Spices - Volume 3

Irradiation to decontaminate herbs and spices 65

microbiological quality during storage. A comparative study was undertaken to evaluate

the effectiveness of radiation processing by six research laboratories in India. As

shown in Table 3.9 all six laboratories reported the effectiveness of radiation processing

in eliminating microbial load on three major spices. Table 3.10 shows the comparative

effectiveness of irradiation with fumigation on some spices and dry vegetable seasonings

(Farkas, 1988). It is evident that irradiation at 10 kGy was much more effective than

ethylene oxide at 800 g/6h.

It has been shown in several studies that the quality parameters of spices do not

change appreciably after radiation processing. Table 3.11 shows the color power of

turmeric (curcumin content) during storage at ambient temperature. It is also evident

that the color power of irradiated (10 kGy) stored turmeric was better in comparison

with the control. Table 3.12 shows that the active ingredients of spices are not

affected by irradiation. In the case of chili the extractable color, capsanthin, was not

found to be significantly affected by irradiation and storage (Table 3.13). Table 3.14

Ta ble 3.9 Microbiological analysis of spices

Spice CFU/ g*

LAB** 1 2 3 4 5 6

Pepper W*** 7 ¥ 105 2 ¥ 106 2 ¥ 104 3 ¥ 105 2 ¥ 108 3 ¥ 106
G1 ¥ 105 7 ¥ 104 3 ¥ 104 9 ¥ 105 3 ¥ 108 3 ¥ 106
IW NIL 30 NIL 9 NIL NIL
IG NIL 30 NIL 20 NIL 60
Chili W 6 ¥ 104 5 ¥ 104 1 ¥ 104 2 ¥ 105 1 ¥ 105 2 ¥ 104
G5 ¥ 104 5 ¥ 104 2 ¥ 104 3 ¥ 105 7 ¥ 105 3 ¥ 105
IW NIL 30 NIL 90 NIL 10
IG NIL 30 NIL NIL NIL 20
Turmeric W 6 ¥ 104 5 ¥ 105 3 ¥ 104 3 ¥ 105 1 ¥ 108 2 ¥ 106
G6 ¥ 105 1 ¥ 106 2 ¥ 104 1 ¥ 106 4 ¥ 105 3 ¥ 106
IW NIL 30 NIL 36 NIL 10
IG NIL 30 NIL NIL NIL 20

• CFU: Colony forming units, each value represents readings average of four replicates from samples.
  ** Laboratories:
  1 Bhabha Atomic Research Centre, Mumbai.
  2 Analytical Quality Control Laboratory, CFTRI, Mysore.
  3 Central Food Laboratory, Kolkata.
  4 Central Food Laboratory, Pune.
  5 University Department of Chemical Technology, Mumbai.
  6 Food Research & Standardization Laboratory, Gaziabad.
  *** W – Whole, G – Ground, IW – Irradiated whole, IG – Irradiated ground.

Table 3.10 Comparison of efficacy of irradiation and fumigation

Spice Log CFN/g Dose (kGy)

048 10ETO

800 g/6h

Pepper 5.5 2.9 1.2 0 3.8
Paprika 3.2 1.0 <1.0 0 1.9
Onion powder 2.8 <1.0 0 0 <1.0
Garlic powder 4.1 3.3 2.0 0 3.8