Tricks, Treats and…Razor Blades??

Kelly Hall Blog Leave a Comment

Halloween is a time for costumes, candy and trick-or-treateNYT-Quoters anxiously knocking on doors.
It is a time for ghost stories, scary movies and that too-much-sugar bellyache that is a sure sign of a successful night.

AND according to newspapers in the ’70s, Halloween is also a time for razor blades in apples, poisoned candies, glass-filled chocolates and of course, the resulting injuries, illnesses and deaths of children across North America.

We’re not making this stuff up!
…but somebody was.

A wave of fear emerged in 1970s North America when rumors that razor blades and poison were being handed outNewsWeek-Pumpkin to unsuspecting trick-or-treaters. Laws were passed to deter criminals, schools taught inspection practices and some places tried to ban trick-or-treating all together.

Despite the fact that most reported cases proved to be Halloween hoaxes planted by children and parents (tsk tsk!), the media and governing bodies served to perpetuate the public’s fear until an urban legend was born.

As a result, over the decades since, parents across North America have been welcomed into select hospitals and clinics to bring their children’s Halloween candy in for a free X-ray to check for razor blades and other contaminates such as needles.

The use of X-ray to inspect candy is fairly limited in that metallic contaminates are the easiest to detect. This is great news for those razor blades, but who really wants apples on Halloween anyways? EVERYONE knows that there is really only one BIG jackpot when it comes to trick-or-treating: chocolate.

Terahertz Image

A TeTechS scan of a square of chocolate containing a protruding and sub surface shard of glass.

With that in mind, terahertz has shown its potential to be used for food inspection purposes including scanning a chocolate bar for dangerous contaminates before consumption. On the one hand, metals may be easily detected with X-ray but other possible contaminates such as plastic, wood and glass are harder to find due to similar densities and a lack of contrast. Unlike X-ray, terahertz scans consider both the amplitude and the phase information, allowing the contrast in both metallic and dielectric contaminates such as glass to appear much more pronounced at terahertz frequencies. Although terahertz is limited to lower water-content items – apples for instance are 85% water – the technology has the ability to provide a clear picture of just how big the contaminate is and where exactly it is located.

Historically speaking, the urban legend surrounding candy tampering has been proven as just that – an urban legend – but the concern will not likely waiver any time soon. Fortunately, terahertz offers a safe alternative to scanning foods like candy for contaminates as it utilizes safe radiation versus the harmful radiation of an X-ray.  This means that kids could one day have their own terahertz scanner at home just in case that “kindly old woman down the block” does in fact have it in for the neighbourhood.


Happy Halloween!




The Razor Blade in the Apple: The Social Construction of Urban Legends
Joel Best and Gerald T. Horiuchi Social Problems Vol. 32, No. 5 (Jun., 1985) , pp. 488-499
Published by: Oxford University Press on behalf of the Society for the Study of Social Problems
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“Pins and Needles.” Snopes.

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