Resistance of new generation food-packaging films against various species of primary and secondary stored-product pests

Bc. Kshitiz Pokhrel

Master's thesis

Abstract:

Infestation by stored-pests is a world-wide problem, it is responsible for infestation of processed, semi-processed and raw food. It directly influences in food safety as well as food security. Stored-pest can be divided into two groups: penetrator (ability to chew holes directly in packaging materials) and invaders (enter package through the existing opening). The main aim of this thesis is to evaluate the protective abilities of selected food-packaging foils against infestation of variously stored product beetles. We observed the Penetration test using a Hou's apparatus, where we tested resistance of four films (i.e. PP 20, PE 50, PP 40 and PET/PE 12/70) to penetration was tested against 6 types of pests (R. dominica, S. oryzae, T. castaneum, T. confusum, P. ratzeburgii and larvae of T. confusum). Another aim of this thesis is to elucidate, invasion test of whole packages of rice (polyethylene mono-layer with thickness 50 μm) under optimum temperature and relative humidity. Usually, there are two ventilation holes on either side of the package of rice, which is made by the manufactures. We performed our experiment in Lock and Lock plastic container of size 180×110×110 mm. Every container containing one 1000 g package of rice and we kept filter paper to provide better movement for the pests. We found that R.dominica can penetrate slightly more holes in the wild spectrum of films then S. oryzae. While the numbers of all injury in tested foils was created slightly more by S. oryzae then R.dominica. Surprisingly we found that R. dominica created more fully penetrated holes in PP 40 than in PP20. While in the invasion test, we observed no synergy effects between R.dominica and S. oryzae while they were kept together. The ventilation holes made by the manufactures were enough for pests to invade ( gain entry), but the secondary pests invade only in a few samples.

Keywords

Infestation, stored-pests, R. dominica, S. oryzae, T. castaneum, T. confusum, P. ratzeburgii, penetrator, invaders, packaging- films, ventilation-holes

Language used: English

Date on which the thesis was submitted / produced: 12. 4. 2019

Thesis defence

• Supervisor: doc. Ing. Lenka Kouřimská, Ph.D.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme / field:
Sustainable Agriculture and Food Security / Sustainable Agriculture and Food Security