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Can you identify this UFO foreign body?

By 16th April 2019 Discussion

Can you help one of our readers to identify this foreign body?

Background: 1mmx1mmx5mm

The clues

The facts are we know them are:

  • the common ingredients are raisins, sultanas, pumpkin seeds and sunflower seeds
  • it’s dry, hard and very light
  • it’s sinks in water

Can you help?

If you can think of what it might be – please add your thoughts to the reply box below!


Thank you so much to everyone that helped to solve this.  We did it in just 15 minutes with the help from our lovely readers all over the world!  Shows what we can do when we help each other – it’s pretty amazing!

The foreign body is called Tribulus terrestris (see link for more details).


  • Chris Rotherham says:

    I know its from the raisins or sultanas from when I used to be involved in making muesli as we used to see them occasionally.
    Cant remenber what it is though!

    • Fiona Millman says:

      I have also seen it with dried vine fruits it’s a type of black rubber / sponge material they use, the X-ray and scanners should be picking it up . I have audited the dried vine fruit suppliers contact me if they need an audit carrying out or the bests packing sites to but from

    • Dorset Smokery says:

      It’s a small Bat that r00sted in a kiln flue got smoked and subsequently covered in tar.. A delicacy in West Bromwich

  • Derek Croucher says:

    Hard to tell without actually seeing it, but it looks as if it’s part of the central base of a pumpkin
    We have seen these on occasion in pumpkin seeds

  • Jen says:

    Dried horse-chestnut shell from field margins of sunflower / pumpkin?

    • Hasan says:

      it is kind of plant that is called Tribulus terrestris and it has many spikes on it.Grapes are evenly spreaded out on the fabric-mat on floor.during harvesting Tribulus terrestris might be pick up.

      • Maria says:

        Hi there all,
        Hasan is right. You can also find the same foreign body in many agricultural products with light processing (like sorting, sun-drying etc) like sultanas, mustard seed, canola seed, sunflower seeds etc. Very common in the northern hemisphere.
        Colour may vary from black to light brown (colour also depends on previous processing. It can be separated by sieving, or by air-producing equipment.

  • Dawn Taffinder says:

    I think this is part of the sunflower head where the seeds sit

  • Fredlyn Sias says:

    Looks like some type of thorn from a plant.

  • Emma Sanderson says:

    We have had exactly the same issue this month , photo is identical and ingredients are the same ,


  • John says:

    Definitely looks like something from another planet!!

    Is it metal detectable or magnetic?

    Has it potentially been through a cook process? (i.e. has the cook changed its appearance?)

    If we get a foreign body that we can’t get our head around we have a ‘competition’ in the factory, usually involving a £50 – £100 bonus to anyone who can solve the puzzle.

    A slightly more expensive route is Campden BRI- not sure if they do foreign material identification. I am aware that they can test glass and plastics to find a likely cause.

    I hope you get to the bottom of it.

  • Steve Turnell says:

    A bit of curve ball but it looks like a decaying pipistrelle bat!!

  • Kirk Eggleston says:

    They appear to be goat head stickers. Very prevalent in sandy soil and grow in fields with sunflowers.

  • Mr John Ahrens says:

    Looks to me like a dried seed head or similar from field hedge row plant, it reminds me of some thing I have seen in the Turkish or Greek countryside.

  • Anna says:

    Part of the dried stem of a sunflower

  • Elsabe Engelbrecht says:

    We know it as a “duwweltjie” in Afrikaans or Devil’s Thorns. Scientific name is Tribulus terrestris

  • It could be an overcooked product blend residue that dislodged and ended in edible product flow,, however since the issue here is there is a repeated situation finding these, it is very subjective to circumscribe our judgement to the ingredients only. I think all Food Contact Surfaces, Zone 2 environment, Pre-Op inspections need to be considered, as well.

  • Marcin says:

    Dose it get pick up on metal detention?
    Fe; Non-Fe, St?

  • Jo says:

    It may be volcanic rock? Dry, hard and light in weight but sinks in water. Volcanic soil is fertile and good for growing grapes … Hard to tell from the photo.

  • Steve Warwick says:

    Where / how was it found? MD? X-Ray? By chance in sorting? End user?
    Has it been sent off for testing?
    Sorry, answering a question with more questions but it’s really hard to tell from pictures alone!

  • Trevor says:

    To me it looks like a part of a dried devils thorn which we refer to in South Africa a duwweltjie. It is common in fields between crops where weed management is poor. You can view a picture of a green seed on Wikipedia by typing in “duwweltjie”. Have seen a view amongst pre-sorting of raisins

  • Joanne Allen says:

    Hi could this be a piece of carbon from the drying process of the fruit, or if the ingredients come from suppliers in bags could this be melted plastic from a machine. I would send this for Lab testing to breakdown what the material is.

  • Marius Voigt says:

    Elsabe Engelbrecht is 100% correct. If you walk in a field with these thorns with soft shoes you will find them stuck in numbers below your shoes

  • Richard Silveira says:

    My first thought was Puncture Vine, also called Goat Head ???

  • Picey says:

    Part of Sunflower base left after de-seeding, it is usually spiky and very light in weight.

  • Lee Bladon says:

    It is a dried capstem – the part of the plant that the grape is attached to.

  • Gareth Parkinson says:

    Certainly organic, that’s certain.

    I personally think the best suggestions are both the capstem from either fruit or from the top of a pumpkin (a small one) or it is indeed dried Tribulus terrestris.

    A google image search for Tribulus terrestris yields a lot of photos that look similar, albeit green.

    Certainly a point to raise with the suppliers of the raw materials.

    What procedures are in place to minimise. Is the manufacturer using the raw materials breaking up or sieving where possible?

    Whilst sieving may not seem counterproductive, you could sieve pumpkin seeds through a 4mm mesh and this would have been separated. On a breakup table, this may have been spotted.

    We often can focus on identifying the foreign body too much at times, rather than focusing on preventing its reoccurrence. It’s useful to know where fbs come from, but it’s often vital we put in simple steps to prevent them happening again.

  • Milena says:

    Definitely it’s dry part of the plant

  • Melina Rodriguez says:

    it´s seams to be part of the fruit/ of tribulist terrestris , or like we call here in Argentina, “ABROJO”.

  • Rachel says:

    I think I’ve has this in vine fruit before. From memory it was a thorny plant which got affixed to the fruit. I’d definitely speak to your dried fruit suppliers as I expect they’ll be familiar with it.
    RSSL or others labs should be able to easily confirm it to be plant origin. Good luck

  • Simon says:

    I would say some sort of planting material From the base of the plant

  • Magda says:

    Raisins or sultanas. Dry pieces of bush/tree. Seen it before when I did some work for bakery.

  • G.Khan says:

    It seems as if it is a residue from the ingredients.
    Very difficult to be exact as it is difficult to interpret from a picture

  • Geoff Marsh says:

    Its a fairly common foreign seed found in many seeds but in particular Pumpkinseed and Sunflower. It is fairly easy to remove by sieving, gravity tabling and colour sorting (all services that we offer). It may occur in dried fruit but we do not process fruit so I am not familiar with impurities found in it.

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