News From Terre Haute, Indiana

Z_CNHI News Service

September 9, 2013

Why is some deli meat iridescent?

Q. What causes some sliced deli meats to possess an iridescent sheen? On occasion, a slice of ham or beef will exhibit the sort of rainbow spot one might see on an oil slick or the inside of a seashell. Why?

               

A. It's because of the particular way light bounces off the surface of the deli meat, a phenomenon known as "diffraction." A piece of meat is composed of strands of fibers that are tightly packed together in parallel bundles. After meat is sliced, the cut ends of the fibers form a series of grooves, like the top of a picket fence. White light is composed of a spectrum of different colors, and each one of those colors has a specific wavelength. When white light hits the grooves on the surface of a deli meat slice, some of the light is absorbed and some of it is reflected. Each component color wave of the reflected light bends at a different angle depending on its particular frequency. The result of this spread of color waves is a kaleidoscope or iridescent effect, similar to the colors we see in soap bubbles, CDs and fish scales.

Diffraction depends on the grooves being structurally intact and perfectly aligned. This is why you're much more likely to see this rainbow effect on processed deli meat that's cooked and/or cured than on raw meat. The former has a firmer, tougher texture and the picket fence structure keeps its shape well when deli meats are sliced. Raw meat, on the other hand, is softer and more delicate, and the ends of the meat fibers are easily damaged when the meat is cut, which means that light is reflected in a haphazard way that doesn't result in rainbows.

So why do some deli meats shimmer while others remain dull? The color of the meat matters. Dark cooked meat like roast beef and bright cured meat like ham are more likely to show iridescence because the background colors provide a starker contrast to the pearly greens and orangey reds that you're most likely to see coming off of shiny meats. Turkey and chicken are too pale to showcase such sparkle. It also matters whether the deli product contains ground or "restructured" meat (in which chopped meat is molded together) or is composed of a single piece of muscle. In the former case, the jumbled up meat fibers are no longer aligned correctly to diffract light.

The way a joint of meat is sliced at the deli counter or before being pre-packaged is also paramount. Only cuts that are sliced against the grain, or perpendicular to the direction of the meat fibers, show iridescence, since the protruding severed ends of the fibers produce the fine grooves. (For beef, these cuts are brisket, which is used for corned beef, and top round, used for pastrami, and navel, used for roast beef.) The sharpness of the blade with which the meat is sliced makes a difference, too. The sharper the slicing instrument, the cleaner the cut, the smoother the surface, and the more intense the display of rainbow hues. Blunt knives produce rough surfaces; the picket fence grooves will be too disrupted to produce iridescence.

The commercial curing process can cause sliced deli meats to have an especially smooth surface, which is why you sometimes see dazzling rainbows on cured hams. Cured meats are first injected with a brine or marinade and then tumbled in revolving metal drums to allow the brine to penetrate evenly throughout the meat. This process causes proteins to seep out from cells and fill gaps between muscle fibers, creating an even, consistent texture that's more likely to diffract light when sliced.

Fat content also has an impact on the light-reflecting properties of meat: A particularly fatty cut of meat is unlikely to diffract light. A slice of roast beef that's richly and evenly marbled with fat won't shine. Fat is either liquid (at room temperature) or semi-crystalline (when chilled), and neither of these states possess the right grooved structure to create a rainbow sheen.

 Since diffraction is a purely physical phenomenon and has nothing to do with microbial growth, iridescent deli meat poses absolutely no safety risk, nor does it have any effect on taste. But this might not always be the case with raw meat, which can occasionally exhibit iridescence. Raw meats are more prone to bacterial contamination, and a colorful glow could be caused by light reflecting off a surface film of liquid produced by microbes. To determine whether your iridescent raw meat is unsafe, lightly wipe the surface of the meat with a paper towel. If the sheen disappears, then the meat is likely harboring slime-producing microbes, and you should discard it.

               

       

 

1
Text Only | Photo Reprints
Z_CNHI News Service
  • Victimized by the 'marriage penalty'

    In a few short months, I'll pass the milestone that every little girl dreams of: the day she swears - before family and God, in sickness and in health, all in the name of love - that she's willing to pay a much higher tax rate.

    April 15, 2014

  • Allergies are the real midlife crisis

    One of the biggest mysteries is why the disease comes and goes, and then comes and goes again. People tend to experience intense allergies between the ages of 5 and 16, then get a couple of decades off before the symptoms return in the 30s, only to diminish around retirement age.

    April 15, 2014

  • Lindley, Tom.jpg Wildcats aren't champs but we're all still watching Calipari

    Kentucky coach John Calipari is a college basketball phenom for his ability to knit together championship-caliber teams of freshmen. How long will Calipari's success last as other coaches catch on?

    April 15, 2014 1 Photo

  • treadmill-very-fast.jpg Tax deduction for a gym membership?

    April marks another tax season when millions of Americans will deduct expenses related to home ownership, children and education from their annual tax bill. These deductions exist because of their perceived value to society; they encourage behaviors that keep the wheels of the economy turning. So why shouldn't the tax code be revised to reward preventive health?

    April 15, 2014 1 Photo

  • bomb1 VIDEO: A year after marathon bombing, Boston remains strong

    The City of Boston came together Tuesday to honor those who were injured and lost their lives at the Boston Marathon on the one-year anniversary of the bombing. While the day was sure to be emotional, those affected by last year's race are showing they won't let the tragedy keep them down.

    April 15, 2014 1 Photo

  • Google acquires drone maker Titan Aerospace to spread Internet

    Google is adding drones to its fleets of robots and driverless cars.
    The Internet search company said it acquired Titan Aerospace, the maker of high-altitude, solar-powered satellites that provides customer access to data services around the world. Terms of the deal weren't disclosed.

    April 14, 2014

  • E-Cigarettes target youth with festivals, lawmakers say

    The findings, in a survey released Monday by members of Congress, should prod U.S. regulators to curb the industry, the lawmakers said. While e-cigarettes currently are unregulated, the Food and Drug Administration is working on a plan that would extend its tobacco oversight to the products.

    April 14, 2014

  • Search teams will send unmanned sub to look for missing Malaysian airliner

    Teams searching for a missing Malaysian airliner are planning for the first time to send an unmanned submarine into the depths of the Indian Ocean to look for wreckage, an Australian official leading the multi-nation search said Monday.

    April 14, 2014

  • Why Facebook is getting into the banking game

    Who would want to use Facebook as a bank? That's the question that immediately arises from news that the social network intends to get into the electronic money business.

    April 14, 2014

  • Screen shot 2014-04-11 at 4.49.09 PM.png Train, entertain your pets with these 3 smartphone apps

    While they may not have thumbs to use the phone, pets can benefit from smartphone apps designed specifically for them.

    April 11, 2014 1 Photo

  • Stepping forward: The real Colbert

    Letterman changed the late-night TV game between his run on NBC's "Late Night" and starting the "Late Show" franchise in 1993. And while it's tough to replace a pop-culture icon, Colbert, in terms of pedigree and sense of humor, makes the most sense.

    April 11, 2014

  • Millions of Android phones, tablets vulnerable to Heartbleed bug

    Millions of smartphones and tablets running Google's Android operating system have the Heartbleed software bug, in a sign of how broadly the flaw extends beyond the Web and into consumer devices.

    April 11, 2014

  • mfp file Hoffner Fired coach unjustly accused of visiting porn sites

    The president of Minnesota State University-Mankato accused a football coach of looking at Internet porn on a work computer before firing him, an arbitrator has revealed. The official said the claim could not be supported, and the coach shouldn't have been fired.

    April 11, 2014 1 Photo

  • 25801486.jpg VIDEO: Northern California bus crash kills 10

    At least nine people died in Northern California on Thursday night, in an accident involving a bus, a car and FedEx truck. The bus was filled with high school students from Southern California who were on their way to visit a college campus.

    April 11, 2014 1 Photo

  • taylor.armerding.jpg Obama's equal pay exaggeration leads us all into danger

    The president's claims of national shame over gender-based pay inequity spring from distorted calculations, as well as some convenient political math.

    April 11, 2014 1 Photo

  • mfp file Hoffner Big win for college coach wrongly accused of child porn

    The ex-coach of Minnesota State University-Mankato - cleared on child porn charges - gets his old job back or could take the difference in pay should he decide to stay in a new position in North Dakota, an arbitrator has ruled. Todd Hoffner was accused when a technician found videos of his young children on his school-issued cellphone. Officials in Mankato fired him even though a judge had thrown out the charges.

    April 10, 2014 1 Photo

  • Teens trading naked selfies for mugshots

    Will teenagers ever learn? You think yours will. Maybe so. But it's likely that was also the hope of the parents of children who were so shamed by nude photos of themselves that went south - how else can they go - that they killed themselves.

    April 10, 2014

  • Boston doctors can now prescribe you a bike

    The City of Boston this week is rolling out a new program that's whimsically known as "Prescribe-a-Bike." Part medicine, part welfare, the initiative allows doctors at Boston Medical Center to write "prescriptions" for low-income patients to get yearlong memberships to Hubway, the city's bike-share system, for only $5.

    April 10, 2014

  • Lindley, Tom.jpg Too much of a good thing at UConn?

    The Connecticut Huskies dominate women's college basketball - which makes for a boring game.

    April 10, 2014 1 Photo

  • DayCareCosts.jpg Day care's cost can exceed college tuition in some states

    Most parents will deal with an even larger kid-related expense long before college, and it's a cost that very few of them are as prepared for: day care.

    April 10, 2014 1 Photo

  • VIDEO: CBS taps Colbert as Letterman’s Late Show successor

    Bloomberg’s Jon Erlichman reports that CBS has announced Stephen Colbert as its choice to replace the retiring David Letterman as host of “The Late Show” on Bloomberg Television’s “Lunch Money.”

     

    April 10, 2014

  • Screen Shot 2014-04-10 at 10.25.07 AM.png VIDEO: Cement truck crashes into minivan

    A professor at Texas A&M University was fortunate to escape serious injury recently when a cement truck ran a red light at a College Station intersection and crashed head-on into his minivan. A dash camera that Dr. Guan Zhu had installed about a year ago captured the entire incident.

    April 10, 2014 1 Photo

  • 2012_Mazda6_--_NHTSA.jpg Brakes, steering and...spiders? What's behind the latest auto recalls

    11 million vehicles have already been recalled in 2014 for everything from power steering failure to vulnerability to spider attack.

    Check out the full list of 2014 recalls.

    April 9, 2014 1 Photo

  • Screen Shot 2014-04-09 at 5.06.43 PM.png Spartans mourn passing of 'Princess Lacey'

    Lacey Holsworth, the 8-year-old cancer patient from Michigan who befriended Michigan State forward Adreian Payne and established a bond with his teammates before and during the Spartans’ run to the Elite Eight, died at her home late Tuesday night, her family said.

    April 9, 2014 1 Photo

  • Screen Shot 2014-04-09 at 4.02.29 PM.png VIDEO: Nebraska prom mishap goes viral

    A group of 22 high school students from Pierce, Neb., all decked out in prom finery, took an unplanned dip in a four-foot-deep pond when the bridge they were posing on for pictures gave way. Photos from the incident have gone viral on social media.

    April 9, 2014 1 Photo

  • Is a paleo vegetarian diet possible?

    Research shows most people can follow a regimented eating plan for a short time. That's not the challenge. The challenge is finding a healthful eating plan you can follow day after day and achieve your long-term health goals. At this point, it doesn't appear that the paleo eating plan meets these objectives for most people.

    April 9, 2014

  • 10 tips for surviving a severe allergy season

    My colleague Brady Dennis reported recently that the arrival of warmer weather will soon unleash a pollen tsunami in parts of the country where the winter has been especially long and cold. Here are some survival tips from Clifford W. Bassett, an allergy specialist and assistant clinical professor of medicine at the New York University School of Medicine.

    April 9, 2014

  • 140407_GT_OUT_Forster_1.jpg Revolutionary War flag could fetch millions at auction

    An iconic piece of history from the Revolutionary War is up for auction through Doyle New York, an auction and appraising company in New York City.

    April 9, 2014 1 Photo

  • pix_internet_security_01.jpg 'Heartbleed' flaw leads security experts to urge password changes

    Security experts are urging consumers to change their Web passwords after the recent disclosure of a vulnerability touching wide swaths of the Internet, even as Google, Facebook and large banks said they weren't affected.

    April 9, 2014 1 Photo

  • Lindley, Tom.jpg Taking someone out to the ballgame gets expensive

    Families in big-league cities like Boston and New York pay steep prices to catch a baseball game. It's not so expensive everywhere - especially if you're frugal.
     

    April 8, 2014 1 Photo

Latest News
TribStar.com Poll
AP Video
NASA Showcases Lunar Eclipse Ukraine: Military Recaptures Eastern Airport Raw: Storm Topples RVs Near Miss. Gulf Coast Pistorius Cries During Final Cross-Examination Raw: Kan. Shooting Suspect Faces Judge Tributes Mark Boston Bombing Anniversary Raw: Horse Jumping Inspires 'Bunny Hop' India's Transgenders Celebrate Historic Ruling Police: Woman Stored Dead Babies in Garage First Women Move to Army Platoon Artillery Jobs US Supports Ukraine's Efforts to Calm Tensions Michael Phelps Set to Come Out of Retirement The Boston Marathon Bombing: One Year Later New Tactic Deployed in Search for Plane Scott Brown Announces Run for U.S. Senate in N.H Sex Offenders Charged in Serial Killings Popular Science Honors Year's Top Inventions Suspect in Kansas Shootings Faces Murder Charges OC Serial Murder Suspects May Have More Victims Police: Blast in Nigerian Capital Kills 71
NDN Video
8-year-old Boy Gets His Wish: Fly Like Iron Man Toddler climbs into vending machine Much-Anticipated 'Gone Girl' Trailer Finally Debuts! (VIDEO) Dog and Toddler Wear Matching Outfits in Adorable Photo Series VP Biden: "World witnesses ordinary citizens doing extraordinary things" It's Official! Michael Strahan Joins "GMA" Blood Moon Time-lapse Actress Lake Bell Goes Topless The Five Weirdest Local Taxes in America Applicants Vying for 'World's Toughest Job' Get Heartwarming Surprise Awkward: Crist catches Lt. Gov. insulting him on camera NASA Showcases Lunar Eclipse US Airways Tweets Graphic Photo of Nude Woman Behind the scenes of the Marathon anniversary photo shoot American Airlines Responds After Girl Tweets Alleged Terror Threat 'Joke' Charlie White's "Dancing" Mistake Olympic Great & Baltimore Native Michael Phelps Ends Retirement; Eyes Rio 2014 NFL Draft: Potential Booms And Busts William and Kate Squash Baby No. 2 Rumors With a Wine-Tasting Trip Who Showed Up at Coachella?
Parade
Magazine

Click HERE to read all your Parade favorites including Hollywood Wire, Celebrity interviews and photo galleries, Food recipes and cooking tips, Games and lots more.
  • -

     

    March 12, 2010

activity