NEXT PAGE

Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872

Digital Re-print - November | December 2010 Insect-resistant packaging: The last line of defense

www.gfmt.co.uk

The cereal that I poured into my breakfast bowl this morning underwent a long and perilous

journey. From the day it got harvest-ed and stored into a grain bin, it was under attack from primary pests such as the granary or rice weevils (Sitophilus granarius, S. oryzae).

The grains were possibly fumigated to keep unwanted grain insects from infesting this valuable commodity.

Weeks to months later, the grains were processed into perhaps rolled oats, corn flakes or flour. These processed products were then stored in interior bins made of steel for a period of time until it was ready to be combined with a variety of ingredients, including sugar, nuts, fruits and other enrich-ments.

During all this time stored product pests (SPP) may have been discretely hidden somewhere in the facility ready and waiting for spillage or easy access to the foods. They include the Indianmeal moth (Plodia inter-punctella), grain beetles, (Oryzaephilus spp.), flour beetles (Tribolium spp.) and warehouse beetles (Trogoderma sp.).

The final product was at last placed into

a package designed to display the food item enclosed within.

The package was also made in such a way as to help preserve the freshness and flavour of the contents, to withstand transportation and long term storage (possibly six months) before being put out onto the retail shelves. The warehouse and retail store are addi-tional locations where the invading hoards wait to claim their next meals.

Beetle bitsI am sure that box of cereal I purchased

remained on the shelf for a few days to a couple of weeks before I was lured by its

seductive appearance and promise of fulfill-ing foods.

I have had this box open and in my cupboards now for about a week. All was well until, this morning as I emptied the last remaining bits of cereal into the bowl and began filling the empty spaces with milk. Stuff floated to the top…and it was not good stuff; it was beetle bits and to my trained entomological eye, the most com-mon stored food pest in the world … an adult Indianmeal moth.

There was a lot of time, material and money spent throughout this journey to get that wholesome food product into my

Table 1: Common stored product pests that penetrate and invade food packaging

Pest Latin name Penetrator Invader

Indianmeal moth Plodia interpunctella Mature Larva Larva

Red flour beetle Tribolium castaneum Adult, Larva

Confused flour beetle Tribolium confusum Adult, Larva

Saw-toothed grain beetle Oryzaephilus surinamensis Adult, Larva

Merchant grain beetle Oryzaephilus mercator Adult, Larva

Cigarette beetle Lasioderma serricorne Adult

Drugstore beetle Stegobium paniceum Adult

Warehouse beetle Trogoderma variabile Larva

Insect-resistant packaging:

The last line of defense

©In

sect

s Li

mite

d In

c. 2

010

Grain&feed millinG technoloGy30 | november - december 2010

FeaturePackaging

hands, the consumer, pest free; but they did not succeed.

Did I eat any bug bits? I didn’t get violently sick, although I had

intestinal grumblings this week. Will I buy this product again? Who is responsible for this? I don’t have any other live or dead insects in my cupboard.

So that means they were dead when I got them. How did they get in there?

Well, I happen to have a lot of experi-ence in this area. Let us investigate this ‘consumer complaint’.

Start with the insectsWe should start with the insects first.

There are a number of common pests that will attack food products. We could call these the ‘Evil Eight’ of food packaging (Table 1).

‘Penetrators’ are insects that have a stage that actively attempt to destroy or damage packaging materials to gain entry. ‘Invaders’ on the other hand attempt entry by navigating through existing openings and

channels or those created by ‘penetrators’ or other factors such as damage from handling.

Packages designed to prevent penetration by insects must be robust with thick layers or made of resilient materials. To thwart the invaders from gaining access, packages must be made free from sealing defects or design flaws as well as surviving harsh handling.

Packaging materialsThere are many types of materials that

can be used for consumer packaging. They can be graded into five categories accord-ing to levels of protection from penetrating insect pests:

Modern packaging incorporates multiple layers and thickness of mixed materials such as those listed in Table 2.

Shangdong Yingchun Steel Silo Manufacturing

Shandong Yingchun Steel Silo Manufacturing Co., Ltd.Address: No.101, Beiyi Road, Dongying City, Shandong ProvinceTel: +86 546 8313068Email: ycgbc@silo86.com

“With over 50 years of experience in the industry, we have built a solid reputation for “Yingchun”. This reputation is based on our scientifi c management, advanced processing, strict quality control and excellent after sales service.

We will stick to our tenet of “Quality fi rst, credit uppermost, customer guided, common development” and provide the best products and services for you”

TRUTH - INNOVATION - PURSUIT OF EXCELLENCE - QUALITY - PEOPLE ORIENTED - PROFOUND KNOWLEDGE

Shangdong.indd 1 01/06/2010 11:35Grain&feed millinG technoloGy november - december 2010 | 31

Feature Packaging

products that have been invaded by a food pest; much fewer cases are from active pen-etration of insects through packages.

It is a rare occurrence that food products are actually manufactured or packaged with active and viable insects. The risk of infesta-tions come post production and packaging.

This is why the packaging material is criti-cal; it is the last line of defense to keep the food pest free.

Compromised by designUnfortunately, it is not uncommon for the

manufacturer to use a package that is com-promised by design during the filling process.

Stitched paper bags have ready-made holes that allow flour beetle and Indianmeal moth larvae to enter the package (see Figure 1). Some conveyor belts have ‘gripping teeth’ to move poly-ethylene bags of heavy product along the system.

These leave openings that often are greater than 100 microns (0.1mm) in diam-eter.

This is the minimum diameter for easy invasion of first instar larvae and egg deposi-tion by female beetles and moths.

It has been discovered, that freshly hatched eggs of flour beetles (Tribolium) can penetrate the stationary 150 mesh screens in a sifter; that is a 50 micron hole.

Adult flour beetle require openings at least 1.35mm and adult grain beetles only require openings 1.0mm in diameter to invade packages.

Moth larvae can gripRecently the author has seen a trend

er’s improper product rotation or lack of pest control services, or its placement next to other infested materials.

The manufacturer must however, sat-isfy the consumer’s expectation of pest free food. That manufacturer has a branded name product and if a consumer cannot feel confident in that product they will remember that brand as one to avoid rather than one to purchase.

To that end, the retail package that a manufacturer uses to proudly sell its product is the ‘Last Line of Defense’. The difference between profit and loss (from recall) can literally be the thickness of the Euro bill (100

microns).

OdorWhy does

an insect attack one package over another made of the same material and containing the same food prod-ucts? The answer is odor; insects live in a world of odors and the escape of food odors from a puncture, loose seal or badly design package is the main reason they choose one package over another.

The majority of consumer com-plaints come from

The purpose of these packaging materials include better preservation, longer shelf life, enhanced graphics, resealable closures, and user convenience. There are however, many food packages that still have nothing more than dry food product in a single layer Kraft paper box or cellophane wrapper.

Why would food manufacturers still do this kind of thing?

Once the food package leaves the ware-house of the food manufacturer, a significant degree of control is lost over that product. It cannot accurately gauge the level of sanita-tion in a distribution center or retail store.

The manufacturer cannot foresee a retail-

Table 2: Common packaging materials and the level of protection they provide from insect penetrators

Level of Protection from Penetrators Examples of packaging materials

Impervious to attack Vacuum sealed jars and tin cans

Insect proof Polycarbonate; Polyethylene terephthalate (PET)Polyester; nylon plastics

Insect resistant Cellulose AcetatePolyamidePolyethylene (250 microns = 10 mil)PolypropylenePolyvinyl chloride

Susceptible to attack AcrylonitrilePolylactic acid (new biodegradable plastics)Polyethylene (125 microns)

No protection from attack

Ethylene vinyl acetateKraft PaperCorrugated paperboardPaper/foil/polyethylenePolyethylene (25-100 microns =1- 4 mil)Polyvinylidene chloride (Saran)

Grain&feed millinG technoloGy32 | november - december 2010

FeaturePackaging

I checked the ‘expiration date’ on the box and noted about one week left.

I guess that box at the back of the retail shelf finally made it to the front of the shelf the day I walked in. So who is to blame?

Well obviously me for not checking the age of the product.

There was an issue with proper product rotation at the retail store; and possibly a light infestation of insects in this row of food products. We do not know how long this box was at the retailer however; it may have been stored at a distribution center for most of its time. The longer a pack-age sits in an environment before it gets purchased for consumption, the greater risk becomes that it will get infested by invaders or penetrators.

Good stewardshipA food manufacturer must have good

stewardship for its brand; it must protect the product beyond its own walls. The manu-facturer should envision long storage, poor sanitation, rough handling, and even invasions from the ‘evil insect hoards’.

Great food in great packaging develops a great reputation; which can only lead to great profits.

was education of the warehouse manager and the requirement for sanitation. The miller withheld the products from distribu-tion until it was cleaned up.

There was no value in attempting to use that distributor if all he received was complaints and infested products that had to be disposed of. Cheap paper packaging was costing this small miller more in lost product and clients than if they chose a better /more costly package.

The long term benefits of costlier pack-aging out weighted the cost of long term losses.

The reputation of the miller was at stake; the prospects of finding new and more valu-able clients would disappear with one more bad summer.

Back to the breakfast cerealNow that you have an idea of what these

insects are capable of, let us go back to that bag of cereal I encountered.

Close examination with a microscope showed a few punctures and stretched scratches that were most likely a result of the nut pieces or ‘crunchy’ components being pushed down into the bag.

One of the punctures clearly showed the characteristic scraping and stretching that Indianmeal moth larva can create.

The single moth suggests a male had developed and died without find-ing another moth to spend some time with. The small hole most likely was the pathway for the small saw-toothed grain beetle to enter, enjoy some food and eventually experience lonely death as well.

to perforating the sides of 25kg bags with hundreds of holes ‘approximately 50 microns wide’ to allow venting. While the small diameter (some seemed bigger than others) may prevent easy invasion of most stages of insects, these holes provide an opening for ‘penetrators’ to use their mandibles on and increase the size of the hole.

With thin polythene bags late instar Indianmeal moth larvae can grip the edges and pull at the plastic until the opening is large enough to penetrate with its head (Figure 2). The majority of people are physi-cally limited in their ability to see package defects less than 50 microns in size, but they are like broken windows to young and delinquent insect larvae.

The author recently spoke with a man-ager of a corn flour mill who had been receiving dozens of complaints from dis-tribution centers stating that they were shipping bags of corn flour with ‘weevils and flour beetles’.

I asked him if all his packaged products and production lots had complaints.

He said that he eliminated the small paper bags for flour in retail grocery stores and replaced them with PET coated Polyethylene reclosable bags and had not received one complaint of insects from them.

It suddenly dawned on him that his product was being milled pest free; it was the perforated paper bags with the cotton stitches that were the problem.

They were attracting insects from the surroundings in the warehouse and of course being in storage for several weeks became infested.

The solution to this packaging problem

More inforMation:Alain VanryckeghemInsects Limited Inc16950 Westfield Park RoadWestfield, IN 46074 USA

Tel: +1 317 8969300Email: insecthelp@InsectsLimited.comWebsite: www.insectslimited.com

Grain&feed millinG technoloGy november - december 2010 | 33

Feature Packaging

PREVIOUS PAGEwww.gfmt.co.uk

LINKS• Seethefullissue• VisittheGFMTwebsite

• ContacttheGFMTTeam

• SubscribetoGFMTA subscription magazine for the global flour & feed milling industries - first published in 1891

In this issue:

• ‘Profiling’ Flours And Their Value

To End Users

• Global grain & feed markets

• Company profiles 2010/11

November 2010

• Newdimensionintheproductionofhygienisedfeedmeal

• Insect-resistantpackaging:

- The last line of defense

• Low-costNearInfraredTransmissiongrainanalysersforfarmers

ThisdigitalRe-printispartoftheNovember|December2010editionofGrain&FeedMillingTechnologymagazine.Contentfromthemagazineisavailabletoviewfree-of-charge,bothasafullonlinemagazineonourwebsite,andasanarchiveofindividualfeaturesonthedocstocwebsite.Pleaseclickheretoviewourotherpublicationsonwww.docstoc.com.

Topurchaseapapercopyofthemagazine,ortosubscribetothepapereditionpleasecontactourCirculationandSubscriptionsManageronthelinkadove.

INFORMATIONFORADVERTISERS-CLICKHERE

Article reprintsAll Grain & Feed Milling Tecchnology feature articles can be re-printed as a 4 or 8 page booklets (these have been used as point of sale materials, promotional materials for shows and exhibitions etc).

If you are interested in getting this article re-printed please contact the GFMT team for more information on - Tel: +44 1242 267707 - Email: jamest@gfmt.co.uk or visit www.gfmt.co.uk/reprints