Nutritional impact of phytosanitary irradiation of fruits and vegetables

Nutritional impact of phytosanitary irradiation of fruits and vegetables

February 2014Food Standards Australia New Zealand (FSANZ) supports and encourages the dissemination and exchange of information. Information in this presentation is provided under a Creative Commons Attribution 3.0 Australia (CC BY 3.0) Licence, except for the Food Standards Australia New Zealand logo.

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Table of Contents

1Executive Summary 4

1Terminology and abbreviations 6

2Background 7

2.1Regulatory Context and Objectives 7

3Natural variation in vitamin content of fruits and vegetables 8

3.1Cultivar 8

3.2Environment 9

3.3Ripeness 10

3.4Post-harvest storage 11

3.5Processing 11

3.6Analytical methods 12

3.7Summary 13

4Nutrient sensitivity to irradiation 14

4.1Macronutrients and minerals 15

4.2Vitamins 15

4.2.1Vitamin A 15

4.2.2Vitamin C 15

4.2.3Vitamin E 16

4.2.4Thiamin 16

4.3Other non-vitamin bioactive compounds 17

4.4Summary 17

5Effects of irradiation on carotenoids, vitamin C and other bioactive compounds in fruit and vegetable groups 17

5.1Pome fruits 18

5.2Stone fruit 20

5.3Berry fruit 22

5.4Citrus fruit 24

5.5Tropical fruit 28

5.6Other fruit 34

5.7Cucurbit vegetables 36

5.8Fruiting vegetables 36

5.9Other vitamins 38

5.10 Summary of data for phytosanitary irradiation doses 39

5.10.1Fruit 39

5.10.2Vegetables 42

6Nutritional implications of phytosanitary doses of irradiation 44

6.1Apples 45

6.2Apricots and Cherries 45

6.3Strawberry 46

6.4Kiwifruit 47

6.5Mandarin 47

6.6Mango 48

6.7Guava and litchi 49

6.8Other considerations 50

6.9Summary 51

7Conclusions and recommendations 51

7.1Recommendations for risk assessment of irradiated fruits and vegetables 52

7.2Considerations for other vitamins and other bioactive compounds 52

7.3Recommendations for data requirements 53

8References 55

Appendix 1 62

Appendix 2 62

Appendix 3 62

1. Executive Summary

Low level ionising irradiation can be used as a phytosanitary treatment for insect pest control on fruit and vegetables. FSANZ has previously assessed the safety and nutritional impact of using ionising irradiation for phytosanitary purposes on various tropical fruits as well as tomatoes and capsicums, and found that doses of ≤1 kGy do not present a safety or nutritional risk to Australian and New Zealand consumers. It is expected that in the near future FSANZ will receive a number of applications to irradiate a variety of other fresh fruits and vegetables for quarantine purposes.
The objectives of this review were to:

• 
  assess the impact of phytosanitary doses of irradiation on the nutritional quality of fruit and vegetables by:
  

• 
  Investigating the natural variability in vitamin levels in a range of fruits and vegetables
  
• 
  Documenting changes in vitamin composition of fruits and vegetables following irradiation with up to 1 kGy
  
• 
  Considering the dietary implications of any reduction in vitamin levels following phytosanitary doses of irradiation (up to 1 kGy).
  

• 
  Make recommendations to amend data requirements for irradiation of fruits and vegetables.
  

Extensive natural variation occurs in the nutrient composition of individual fruit and vegetable types. The main sources of variation are cultivar, season, growing location and degree of ripeness. Post-harvest storage and processing also affect nutrient composition. Fruits and vegetables are rich sources of vitamin C and carotenes. Substantial data documents the natural variation in levels of these nutrients, with differences of more than ten-fold being common between cultivars.

Phytosanitary doses of irradiation typically range from 0.15 to 1 kGy. At these doses there is no effect of irradiation on macronutrients or minerals. However, the effect on vitamins is less clear, with vitamins A, C, E and thiamin being most sensitive to irradiation. Fruits and vegetables generally have high levels of carotenes and vitamin C but are not major contributors to intakes of vitamin E or thiamin, therefore this review focused on vitamin C and carotenes. Review of the published literature demonstrated that phytosanitary doses of irradiation:

• 
  Had no effect on carotene levels in fruits and vegetables
  
• 
  Did not decrease vitamin C levels in the majority of fruits and vegetables
  
• 
  Had little effect on other non-vitamin bioactive compounds.
  

In some cultivars of some fruits vitamin C levels decreased following irradiation. However, in the majority of these cases the vitamin C content of irradiated fruit remained within the range of natural variation. In addition, when the effects of these changes were compared to dietary consumption patterns it was evident that these changes were unlikely to impact on dietary vitamin C intakes in Australia and New Zealand. As carotene levels were unaffected by phytosanitary doses of irradiation it can also be concluded that carotene intakes would not be compromised.

From these data it can be concluded that phytosanitary doses of irradiation do not pose a nutritional risk to the Australian and New Zealand populations. It is therefore recommended that the data requirements for applications to irradiate fruits and vegetables can be streamlined to focus on data for vitamin C, with requirements for other nutrients to be determined on a case-by-case basis.