The cereal that I poured into my breakfast bowl this morning underwent a long and perilous journey. From the day it got harvested and stored into a grain bin, it was under attack from primary pests such as the granary or rice weevils (Sitophilus granarius, S. oryzae).

1. Digital Re-print - November | December 2010
Insect-resistant packaging: The last line of defense
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2. Packaging Feature Feature Packaging
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 insects
We should start with the insects first.
There are a number of common pests channels or those created by ‘penetrators’ Packaging materials
Insects Limited Inc. 2010
that will attack food products. We could or other factors such as damage from There are many types of materials that
call these the ‘Evil Eight’ of food packaging handling. can be used for consumer packaging. They
(Table 1). Packages designed to prevent penetration can be graded into five categories accord-
Insect-resistant packaging: ‘Penetrators’ are insects that have a
stage that actively attempt to destroy or
by insects must be robust with thick layers
or made of resilient materials. To thwart the
ing to levels of protection from penetrating
insect pests:
The last line of defense
damage packaging materials to gain entry. invaders from gaining access, packages must Modern packaging incorporates multiple
©
‘Invaders’ on the other hand attempt entry be made free from sealing defects or design layers and thickness of mixed materials such
by navigating through existing openings and flaws as well as surviving harsh handling. as those listed in Table 2.
Shangdong Yingchun
T
he cereal that I poured into a package designed to display the food item seductive appearance and promise of fulfill-
Steel Silo Manufacturing
my breakfast bowl this morning enclosed within. ing foods.
underwent a long and perilous The package was also made in such a way I have had this box open and in my
journey. From the day it got harvest- as to help preserve the freshness and flavour cupboards now for about a week. All was
ed and stored into a grain bin, it of the contents, to withstand transportation well until, this morning as I emptied the
TRUTH - INNOVATION - PURSUIT OF EXCELLENCE - QUALITY - PEOPLE ORIENTED - PROFOUND KNOWLEDGE
was under attack from primary pests and long term storage (possibly six months) last remaining bits of cereal into the bowl
such as the granary or rice weevils before being put out onto the retail shelves. and began filling the empty spaces with
(Sitophilus granarius, S. oryzae). The warehouse and retail store are addi- milk. Stuff floated to the top…and it was
tional locations where the invading hoards not good stuff; it was beetle bits and to my “With over 50 years of experience in the industry, we have built a solid reputation for “Yingchun”.
The grains were possibly fumigated to wait to claim their next meals. trained entomological eye, the most com- This reputation is based on our scientific management, advanced processing, strict quality control
keep unwanted grain insects from infesting mon stored food pest in the world … an and excellent after sales service.
this valuable commodity. Beetle bits adult Indianmeal moth.
We will stick to our tenet of “Quality first, credit uppermost, customer guided, common
Weeks to months later, the grains were I am sure that box of cereal I purchased There was a lot of time, material and
processed into perhaps rolled oats, corn remained on the shelf for a few days to a money spent throughout this journey to
development” and provide the best products and services for you”
flakes or flour. These processed products couple of weeks before I was lured by its get that wholesome food product into my
were then stored in interior bins made of
steel for a period of time until it was ready Table 1: Common stored product pests that penetrate and invade food packaging
to be combined with a variety of ingredients, Pest Latin name Penetrator Invader
including sugar, nuts, fruits and other enrich-
ments.
Indianmeal moth Plodia interpunctella Mature Larva Larva
During all this time stored product pests
Red flour beetle Tribolium castaneum Adult, Larva
(SPP) may have been discretely hidden
Shandong Yingchun Steel Silo Manufacturing Co., Ltd.
somewhere in the facility ready and waiting Confused flour beetle Tribolium confusum Adult, Larva
Address: No.101, Beiyi Road, Dongying City, Shandong Province
for spillage or easy access to the foods. They Saw-toothed grain beetle Oryzaephilus surinamensis Adult, Larva Tel: +86 546 8313068
include the Indianmeal moth (Plodia inter- Email: ycgbc@silo86.com
Merchant grain beetle Oryzaephilus mercator Adult, Larva
punctella), grain beetles, (Oryzaephilus spp.), Cigarette beetle Lasioderma serricorne Adult
flour beetles (Tribolium spp.) and warehouse
Drugstore beetle Stegobium paniceum Adult
beetles (Trogoderma sp.).
Warehouse beetle Trogoderma variabile Larva
The final product was at last placed into
Shangdong.indd 1 01/06/2010 11:35
30 | november - december 2010 Grain &feed millinG technoloGy Grain &feed millinG technoloGy november - december 2010 | 31

3. Packaging Feature Feature Packaging
to perforating the sides of 25kg bags with was education of the warehouse manager I checked the ‘expiration date’ on the box
hundreds of holes ‘approximately 50 microns and the requirement for sanitation. The and noted about one week left.
wide’ to allow venting. While the small miller withheld the products from distribu- I guess that box at the back of the retail
diameter (some seemed bigger than others) tion until it was cleaned up. shelf finally made it to the front of the shelf
may prevent easy invasion of most stages of There was no value in attempting to the day I walked in. So who is to blame?
insects, these holes provide an opening for use that distributor if all he received was Well obviously me for not checking the
‘penetrators’ to use their mandibles on and complaints and infested products that had to age of the product.
increase the size of the hole. be disposed of. Cheap paper packaging was There was an issue with proper product
With thin polythene bags late instar costing this small miller more in lost product rotation at the retail store; and possibly
Indianmeal moth larvae can grip the edges and clients than if they chose a better /more a light infestation of insects in this row of
and pull at the plastic until the opening is costly package. food products. We do not know how long
large enough to penetrate with its head The long term benefits of costlier pack- this box was at the retailer however; it may
(Figure 2). The majority of people are physi- aging out weighted the cost of long term have been stored at a distribution center
cally limited in their ability to see package losses. for most of its time. The longer a pack-
defects less than 50 microns in size, but The reputation of the miller was at stake; age sits in an environment before it gets
they are like broken windows to young and the prospects of finding new and more valu- purchased for consumption, the greater risk
delinquent insect larvae. able clients would disappear with one more becomes that it will get infested by invaders
The author recently spoke with a man- bad summer. or penetrators.
ager of a corn flour mill who had been
receiving dozens of complaints from dis- Back to the breakfast cereal Good stewardship
The purpose of these packaging materials er’s improper product rotation or lack of products that have been invaded by a food tribution centers stating that they were Now that you have an idea of what these A food manufacturer must have good
include better preservation, longer shelf life, pest control services, or its placement next pest; much fewer cases are from active pen- shipping bags of corn flour with ‘weevils and insects are capable of, let us go back to that stewardship for its brand; it must protect the
enhanced graphics, resealable closures, and to other infested materials. etration of insects through packages. flour beetles’. bag of cereal I encountered. product beyond its own walls. The manu-
user convenience. There are however, many The manufacturer must however, sat- It is a rare occurrence that food products I asked him if all his packaged products Close examination with a microscope facturer should envision long storage, poor
food packages that still have nothing more isfy the consumer’s expectation of pest are actually manufactured or packaged with and production lots had complaints. showed a few punctures and stretched sanitation, rough handling, and even invasions
than dry food product in a single layer Kraft free food. That manufacturer has a branded active and viable insects. The risk of infesta- He said that he eliminated the small paper scratches that were most likely a result of the from the ‘evil insect hoards’.
paper box or cellophane wrapper. name product and if a consumer cannot feel tions come post production and packaging. bags for flour in retail grocery stores and nut pieces or ‘crunchy’ components being Great food in great packaging develops
Why would food manufacturers still do confident in that product they will remember This is why the packaging material is criti- replaced them with PET coated Polyethylene pushed down into the bag. a great reputation; which can only lead to
this kind of thing? that brand as one to avoid rather than one cal; it is the last line of defense to keep the reclosable bags and had not received one One of the punctures clearly showed the great profits.
Once the food package leaves the ware- to purchase. food pest free. complaint of insects from them. characteristic scraping and stretching that
house of the food manufacturer, a significant To that end, the retail package that a It suddenly dawned on him that his Indianmeal moth larva can create.
degree of control is lost over that product. manufacturer uses to proudly sell its product Compromised by design product was being milled pest free; it was The single moth suggests a male More inforMation:
It cannot accurately gauge the level of sanita- is the ‘Last Line of Defense’. The difference Unfortunately, it is not uncommon for the the perforated paper bags with the cotton had developed and died without find- Alain Vanryckeghem
tion in a distribution center or retail store. between profit and loss (from recall) can manufacturer to use a package that is com- stitches that were the problem. ing another moth to spend some time Insects Limited Inc
The manufacturer cannot foresee a retail- literally be the thickness of the Euro bill (100 promised by design during the filling process. They were attracting insects from the with. The small hole most likely was 16950 Westfield Park Road
microns). Stitched paper bags have ready- surroundings in the warehouse and of course the pathway for the small saw-toothed Westfield, IN 46074 USA
made holes that allow flour beetle and being in storage for several weeks became grain beetle to enter, enjoy some food Tel: +1 317 8969300
Table 2: Common packaging materials and the level of protection Odor Indianmeal moth larvae to enter the infested. and eventually experience lonely death Email: insecthelp@InsectsLimited.com
Website: www.insectslimited.com
they provide from insect penetrators Why does package (see Figure 1). Some conveyor The solution to this packaging problem as well.
an insect attack belts have ‘gripping teeth’ to move poly-
Level of Protection
Examples of packaging materials one package over ethylene bags of heavy product along the
from Penetrators
another made of system.
the same material These leave openings that often are
Impervious to attack Vacuum sealed jars and tin cans
and containing the greater than 100 microns (0.1mm) in diam-
Insect proof Polycarbonate; Polyethylene terephthalate (PET) same food prod- eter.
Polyester; nylon plastics
ucts? The answer This is the minimum diameter for easy
Insect resistant Cellulose Acetate is odor; insects live invasion of first instar larvae and egg deposi-
Polyamide in a world of odors tion by female beetles and moths.
Polyethylene (250 microns = 10 mil) and the escape of It has been discovered, that freshly
Polypropylene food odors from hatched eggs of flour beetles (Tribolium) can
Polyvinyl chloride
a puncture, loose penetrate the stationary 150 mesh screens in
Susceptible to attack Acrylonitrile seal or badly design a sifter; that is a 50 micron hole.
Polylactic acid (new biodegradable plastics) package is the main Adult flour beetle require openings at
Polyethylene (125 microns)
reason they choose least 1.35mm and adult grain beetles only
No protection from Ethylene vinyl acetate one package over require openings 1.0mm in diameter to
attack Kraft Paper another. invade packages.
Corrugated paperboard The majority
Paper/foil/polyethylene
Polyethylene (25-100 microns =1- 4 mil)
of consumer com- Moth larvae can grip
Polyvinylidene chloride (Saran) plaints come from Recently the author has seen a trend
32 | november - december 2010 Grain &feed millinG technoloGy Grain &feed millinG technoloGy november - december 2010 | 33

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