Mystery of the green sheen on Subway roast beef solved

It has been years since my Subway sandwich artist days, but I think I could still make a delicious sub if put behind the counter. I worked there for over three years, during which time I noticed a few odd things. One thing was the roast beef. There was always some green gasoline-like sheen on the slices of deli meat (see right). Whenever I had to make a sub that had roast beef I’d get nervous and concerned the customer would ask what it was – I had no idea – until today.

When reading a story in the Sun Chronicle Online about a Massachusetts Subway’s green roast beef, the memories came back to me and I decided to do some investigating.

A co-worker who worked in a meat laboratory explained to me, and this University of Saskatchewan paper on meat colour agrees, that the odd colour I was seeing was likely due to light reflections on sliced meat muscle fibers (which is not a food safety issue).

From the paper,

Iridescence is a common problem in sliced roast beef and ham products. The dominant color is frequently green and consumers sometimes confuse this with green myoglobin pigments associated with microbial growth. The iridescence of meat products is produced by a combination of the angle of incidence of the light on the muscle fibres and the wetness of the surface. If the fibres are pulled slightly out of alignment during slicing, the light strikes the fibre at an angle scattering light which
appears as the rainbow or greenish color on the surface of the meat. 

Whether or not this explains the green on the Massechusetts Subway’s roast beef, I do not know, but does answer a question I forgot I had.

6 thoughts on “Mystery of the green sheen on Subway roast beef solved

  1. Then how would you know if its bad? There roast beef looks bad black and green looks like it has been laying there for days. How long is roast beef suppose to be kept in the refrigerator. There roast beef has to be shipped after it was sliced how old is it by the time it gets there. I asked for my money back and will not go there. It is not very appetizing to see that. What is wrong with subway?

  2. Well as a subway worker i can tell you that subway gets shipments of meat weekly and rarely does meat last a whole week in the store before its used. Also everything is tagged and dated and subways are inspected quite frequently by food inspectors of the city, food inspectors of the subway fanchise and general district managers, so there is really no way wecould get away with serving bad meat without getting a bad grade o marked out of compliance with the subway franchise. you tll if meat is bad by te texture and off smell of the meat as well. Nothing is wrong with the roas beef ists perfectly normal. The green coloring you want to look for would be more like mold.

  3. I had a sub that had NEON green on the roast beef. I know what this iridescent (sp?) stuff is, I’ve seen it before. The stuff on my roast beef was NEON green, very vibrant no matter which way you looked at it. I asked them to make me a new sub and ordered one without roast beef. Gross. Definitely not appetizing, regardless of whether it’s good for you or not.

  4. Well that makes sense. I work at subway and wondered what the sheen was, had seen it at costco as well on their roast beef. Now I know!

  5. Yeah!!! Finally I don’t have to throw away all my roast beef! I stopped buying meat slices years ago and started making my own sandwich meat, then throwing it out.

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