Ever wonder what those tiny bits of chicken in your nuggets or hot dogs are made of? You’re not alone! As someone who’s been researching food production for years, I’ve discovered that mechanically recovered chicken is way more common in our food than most people realize. Let’s dive into what this ingredient actually is how it’s made and whether you should be concerned about it.
What Exactly Is Mechanically Recovered Chicken?
Mechanically recovered chicken (also called mechanically separated chicken or MSC) is basically a paste-like poultry product created by separating every last bit of meat from chicken bones after the main cuts have been removed. Think of it as the food industry’s way of making sure nothing goes to waste!
The American Meat Science Association defines it as “a low-cost poultry protein, which is produced by mechanically separating bone and attached skeletal muscle” The end result is a finely chopped, batter-like substance that can be used in all sorts of processed foods
How Is Mechanically Separated Chicken Made?
The process is pretty straightforward but might sound a bit industrial:
- After removing the main cuts (breasts, thighs, etc.), chicken carcasses still have bits of meat attached to the bones
- These carcass frames are passed through mechanical deboners
- High pressure forces the remaining muscle and tissue through sieves or plates
- This separates the edible meat from bones, tendons, and gristle
- The result is a paste-like chicken material that can be used in other products
As my grandma used to say, “they use everything but the cluck!” And she wasn’t wrong – this process helps minimize waste in poultry processing.
Is Mechanically Recovered Chicken Safe to Eat?
This is the million-dollar question, right? Despite its not-so-appetizing production process, mechanically separated poultry has been approved for human consumption in the United States since 1969
The USDA Food Safety and Inspection Service (FSIS) regulates MSC with specific standards including:
- Limits on calcium content (which indicates bone presence)
- Maximum bone particle size restrictions
- Proper labeling requirements
- Pathogen reduction treatments to control bacteria
While there were significant restrictions placed on mechanically separated beef due to concerns about BSE (mad cow disease), mechanically separated poultry is considered safe when produced according to regulations.
Nutritional Profile of Mechanically Recovered Chicken
Since MSC contains both meat and skin, it’s typically:
- High in protein (14-16%)
- High in fat (15-20%)
- Contains vitamins and minerals including niacin, vitamin B6, zinc, and iron
- Calorie-dense (around 225 calories per 100 grams)
The nutritional profile makes it useful for food manufacturers looking to add protein and flavor to processed products at a lower cost than whole muscle meat.
Where You’ll Find Mechanically Recovered Chicken
Look at your ingredient list next time you’re shopping! MSC is commonly used in:
- Hot dogs and frankfurters – Can make up to 20% of the recipe
- Bologna and luncheon meats – Used as a binder and protein source
- Chicken nuggets – Often a key ingredient (though McDonald’s claims they don’t use it)
- Canned chicken products – Frequently contains MSC
- Frozen meals – Found in many ready-to-eat options
- Processed sausages – Including chicken frankfurters, salami, and bologna
- Chicken patties – Helps bind the product together
According to studies, MSC products represent about 10% of total daily caloric intake for regular consumers, and make up about 47.3% of the daily calories from ultra-processed products for those who eat them.
Labeling Requirements
In the U.S., FSIS regulations require products containing mechanically separated chicken to be clearly labeled as “mechanically separated chicken” – not simply as “chicken” or “chicken meat.” This labeling requirement helps consumers make informed choices about what they’re eating.
If you see “mechanically separated chicken” on an ingredient list, now you know exactly what that means!
Benefits of Mechanically Separated Chicken
Despite the somewhat unappealing production process, there are some benefits to using MSC:
- Reduces food waste – Utilizes parts that would otherwise be discarded
- Provides affordable protein – Helps keep processed meat products economical
- Similar nutritional value to whole muscle chicken
- Functional properties – Good binding and emulsifying characteristics in processed meats
- Resource efficiency – Maximizes the use of each chicken
Common Concerns and Limitations
I won’t sugarcoat it – there are some legitimate concerns about mechanically separated chicken:
- Higher microbial risk – The breakdown of muscle fibers releases nutrients that can support bacterial growth
- Increased fat content – Often contains more fat than whole muscle meat
- Oxidative rancidity – More prone to developing off-flavors during extended freezing
- Processing aids – May require additional preservatives for shelf stability
- Texture differences – Has a paste-like consistency unlike whole muscle meat
FAQs About Mechanically Recovered Chicken
Is mechanically separated chicken the same as “pink slime”?
No! “Pink slime” refers specifically to lean finely textured beef (LFTB). Mechanically separated chicken is sometimes called “white slime” but is a different product with its own production process.
Does McDonald’s use mechanically separated chicken in their nuggets?
According to McDonald’s, they don’t use mechanically separated chicken in their nuggets. They claim to use ground breast meat instead.
Are there bones in mechanically separated chicken?
While the process aims to remove bones, tiny bone particles may remain. However, regulations limit the maximum bone particle size and calcium content to ensure safety.
Is mechanically separated chicken healthy?
From a nutritional standpoint, MSC contains protein, vitamins and minerals, but is often higher in fat than whole muscle meat. It’s generally found in highly processed foods that nutrition experts recommend limiting in a healthy diet.
The Bottom Line
Mechanically recovered chicken isn’t the mystery meat monster some make it out to be, but it’s definitely not the same as a chicken breast either. It’s a highly processed ingredient that helps keep food costs down and reduces waste in the meat industry.
While it might sound a bit gross when you think about how it’s made (high-pressure meat paste, anyone?), it’s been deemed safe by regulatory agencies and has been used in processed foods for decades.
As with most things in nutrition, moderation is key. If you’re concerned about mechanically separated chicken in your diet, check those ingredient labels and consider limiting ultra-processed foods in general.
What do you think? Are you surprised to learn what goes into some of your favorite processed chicken products? I’d love to hear your thoughts in the comments below!
Proximate composition and pH
Proximate composition was determined on all meat raw materials, raw batters, and finished products. Samples were homogenized using a food processor (model KFP715WH2; KitchenAid, St. Joseph, MI). Protein content was determined by the CEM Sprint Rapid Protein Analyzer (AOAC Official Method 2011.04), moisture content by the CEM Smart 6 system (AOAC Official Method 2008.06), and fat content by the CEM ORACLE system (AOAC Official Method 2008.06) (CEM Corporation, Mathews, NC). All analyses were done in duplicate and averaged.
For pH measurement, 90 mL of distilled, deionized water was added to 10 g of ground sample and mixed vigorously with a glass stirring rod for 30 s, and the mixture was filtered through 11-μm–filter paper (Whatman Grade 1; GE Healthcare Life Sciences, Pittsburgh, PA). The pH of the filtrate was measured using a SevenMulti pH meter equipped with an InLab Solids Pro-ISM electrode (Mettler Toledo, Columbus, OH). Each sample pH was measured in duplicate.
Poultry raw materials were analyzed for hydroxyproline content by NP Analytical Laboratories (St. Louis, MO; internal method code HPHV). Briefly, 250 mg of sample was mixed with 6 N HCl in a modified Kjeldahl flask. After oxygen was removed by pulling a vacuum and repeated freezing and thawing, the flask was sealed and placed in a 110°C oven for 24 h to allow for protein hydrolysis. After cooling, an internal standard was mixed, pH was adjusted to 2.2, and hydroxyproline and internal standard were separated on a sodium cation exchange column by pH gradient elution with a temperature gradient of 53°C to 90°C. The separated amino acids were subsequently reacted with ninhydrin and measured spectrophotometrically, after which fractions were injected into a Biochrom amino acid analyzer (Cambridge, UK), and the concentration of hydroxyproline was determined by comparing with a standard solution of known concentration (Lee et al., 1978; Lin, 1982). Measurements were done in triplicate.
Poultry raw materials were analyzed for calcium and iron content by NP Analytical Laboratories (St. Louis, MO; internal method codes CAF and FEF, respectively). Briefly, 10 g of sample was ashed in a muffle furnace and analyzed by atomic absorption spectroscopy. Absorbance of test samples was compared with that of iron and calcium to determine concentration. Measurements were done in triplicate.
On days 0, 14, 28, 42, 56, 70, 84, and 98 of storage, 3 frankfurters from one randomly selected package of each treatment were homogenized in a food processor (KFP715WH2; KitchenAid, St. Joseph, MI) and analyzed by the modified 2-thiobarbituric acid method for meat products containing sodium nitrite (Zipser and Watts, 1962). A DU 640 spectrophotometer (model 4320940; Beckman Instruments, Inc., Fullerton, CA) was used to measure absorbance at 532 nm. Analyses were performed in duplicate, and results were averaged.
Color was evaluated at days 0, 14, 28, 42, 56, 70, 84, and 98 of storage. Three frankfurters from one randomly selected package of each treatment were scanned by a LabScan XE colorimeter (model LS 1500; Hunter Associated Laboratories, Inc., Reston, VA) using illuminant D65 (daylight at 6,500 K), 10° observer angle and set to the Commission Internationale de l´Eclairage (CIE; “International Commission on Illumination”) L*, a*, b* color space. External color was measured in 2 different locations on each frankfurter’s light-exposed surface using a 3.3-mm aperture. For internal color, frankfurters were sliced in half lengthwise, and 2 measurements were taken in the center with a 6.35-mm aperture. Measurements from the same package were averaged.
Texture Profile Analysis (TPA) was performed on storage days 0, 14, 28, 42, 56, 70, 84, and 98 using a TA-XT2i Texture Analyser (Texture Technologies, Inc., Scarsdale, NY) equipped with a 30-kg load cell. One randomly selected package of frankfurters from each treatment group was analyzed each sampling day. After equilibration to room temperature for a minimum of 5 h, a 2.54-cm-long section was cut from the center of each frankfurter, positioned on a flat end and compressed twice to 50% of its original height with a 5.08 cm (diameter) × 20 mm (height) aluminum probe (TA-25; Texture Technologies, Inc., Scarsdale, NY) at a test speed of 5.0 mm s−1. The TPA parameters measured were hardness, cohesiveness, chewiness, springiness, and resilience. Three measurements were taken from each package and averaged.
Composition of chicken raw materials
Composition of chicken raw materials
| Raw material1 | Moisture (g/100 g) | Fat (g/100 g) | Protein (g/100 g) | pH | Hydroxyproline (g/100 g) | Calcium (g/100 g) | Iron (ppm) |
|---|---|---|---|---|---|---|---|
| CBT | 74.41a | 2.40c | 23.48a | 5.88c | 0.08c | 0.010c | 5.75c |
| MSC1 | 68.35c | 16.17a | 14.40b | 6.82a | 0.21a | 0.248a | 16.57b |
| MSC2 | 71.00b | 14.83b | 14.00b | 6.70b | 0.14b | 0.086b | 18.67a |
| SEM | 0.34 | 0.16 | 0.14 | <0.01 | 0.01 | 0.023 | 0.52 |
Calcium content was very low in CBT (0.01 g/100 g) and higher in both MSC materials, not surprising considering its common use as an indicator of bone matter content in mechanically recovered meat and poultry (Field, 1988). The calcium content of MSC2 (0.09 g/100 g) was lower (P < 0.05) than that of MSC1 (0.25 g/100 g) and 64% lower than the US regulatory limit of 0.235% (9 C.F.R. § 381.173, 2020) established for mechanically separated poultry, which suggests less bone crushing—and subsequent lower incorporation into the final material—during its obtainment process. Iron content for both MSC was 2.5 to 3 times higher than for CBT, which is consistent with reports in the literature (Field, 1988; Koolmees et al., 1986; Henckel et al., 2004), but still slightly higher (P < 0.05) in MSC2 than in MSC1. The relative differences in calcium content (higher in MSC1) and iron content (higher in MSC2) among the two MSC suggests differential incorporation of bone matter and bone marrow into materials from the two separation processes. In a previous study, Crosland et al. (1995) compared MSC obtained by 2 different deboning machine types and observed a higher calcium content in one despite small differences in iron content among them. Subsequently, Field (1999) noted that the calcium content of mechanically recovered products is not a good estimator of the amount of marrow present and suggested that it should not be used for that purpose.
There were significant (P < 0.05) differences in pH among the chicken materials (Table 3). The pH of CBT (5.88) was comparable to that of normal chicken breast reported recently (Li et al., 2015). The pH of MSC is known to be higher due to its bone marrow content (Field, 1988), and in this study, the pH of MSC2 was lower than that of MSC1, which was similar to that reported by Rivera et al. (2000).
Overall, the compositional differences among the two MSC indicate that the MSC2 obtainment process is gentler and results in less incorporation of bone material but probably equivalent amounts of bone marrow.