The AskUSDA site makes it easy to find information regarding food safety all in one place, or connects you with someone who can. Visit ask.usda.gov.

Biofilms are sticky layers of bacteria, proteins, and other biological materials that build up on surfaces like drain traps. They can harbor harmful bacteria such as Listeria, posing a significant food safety risk. To prevent biofilm formation, clean drains daily to remove fats and proteins, use effective sanitizers (like hypochlorites or peracids) followed by detergents and hot water, and make sure cleaning methods reach deep into the drain trap. Remove drain covers when possible during cleaning, use specialized attachments for thorough sanitation, and regularly train staff on proper procedures. Upgrading drain design or materials and separating raw from ready-to-eat area drains can further reduce biofilm risks.

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As the myoglobin in ground beef becomes oxidized, the meat turns more brown; however, it’s still safe to eat as long as it has been stored properly, is within its code date limits, and has no bad smell, slimy texture or visible mold.

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Yes, if the ink comes from approved sources (like USDA food-grade stamps), it’s safe to eat the meat. These inks are made to be edible and won’t hurt you or affect the taste. For any other types of ink, don’t use the meat. Download the Ink on Meat FAQ for more details. 

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To minimize changeover inefficiencies in meat processing, when switching between different products, plan your production schedule to group similar products and allergens together, reducing the need for extensive cleaning and changeover downtime. When possible, use larger batch sizes to reduce the number of changeovers throughout production. Review ingredient lists and schedule batches in an order that minimizes the introduction of new ingredients, which can trigger additional cleaning requirements and increase downtime. Ensure all operators are aware of ingredient and allergen changes, and follow proper sanitation protocols—especially when switching between allergen-containing and allergen-free products—to maintain food safety and regulatory compliance. Read more in this document.

Precise temperature control is vital in cooked meat processing to ensure both food safety and product quality. Undercooked areas can allow pathogens to survive, while excessive heat can dry out or toughen meat. To avoid internal temperature variations, use temperature probes to monitor different parts of the oven and inside various points of the product—aiming for less than a 3°F difference across products and oven zones. Regularly analyze cooking data, adjust oven humidity and airflow for more even heating, and maintain equipment to minimize hot and cold spots. For in-line ovens, consider embedded or real-time monitoring devices. Also, review formulation and processing changes, as well as product size and loading methods, to optimize even cooking and deliver safe, consistent results every time. Read more in this guide.

Temperature control is crucial for uniformly cooked whole-muscle meats like hams and roasts, ensuring texture, yield, and food safety—especially when targeting lower final temperatures. Because these products have irregular shapes and varying moisture content, uneven heating can easily result in undercooked or dry areas. To avoid internal temperature variation, batch similar products together, standardize product temperatures before cooking, and optimize oven conditions by monitoring for hot and cold spots and maintaining high humidity. Always use multiple internal thermometers to check different areas within the muscle, rather than relying on visual checks alone. These strategies help achieve more consistent, high-quality results in every batch. Read more in this guide.

There are two types of streaks that can appear in pumped fresh meat. One type is referred to “tiger stripes”, and is an indistinct grouping of lines through the product the other type of streak is probably pink in color. There are many differences of opinion about what causes tiger stripes, however, some likely causes follow:

• • Needles becoming coated with protein during operation. As the needle moves through the meat it can pick up protein residue due to the presence of salt in the brine. A portion of the residue is forced into the meat by the needles, causing stripes. Needles need to be kept in good condition and cleaned to prevent protein buildup.

• • Another possibility is the water used to make the brine. Excessively hard water can cause streaking as the minerals in the water do not move through the meat. If you are not using softened or RO water in your brines, you should test your water for hardness.

• • The presence of soy proteins in your brine. Soy proteins can be an effective ingredient to improve the water holding capacity and cooking yields of products, however, in some instances, soy proteins can have a small amount of nitrate, which can cause pink streaking.

If you are getting pink streaks in injected fresh meat products the cause is almost certainly due to the presence of nitrate in the brine. Nitrate or nitrites can be accidentally introduces into the product several ways:

• • Using the injector for cured products such as hams or bacons and not adequately cleaning before switching to a fresh meat product.

• • Mixing brines for fresh meat in the same container as a cured was mixed in without proper cleaning.

• • The presence of excessive nitrates in you water. RO water is preferable for most pumping applications as the vast majority of minerals and nitrates should be removed during the RO process.

• • The presence of soy proteins in your brine. Soy proteins can be an effective ingredient to improve the water holding capacity and cooking yields of products, however, in some instances, soy proteins can have a small amount of nitrate, which can cause pink streaking.

It is not uncommon for pump percentages to vary considerably between pieces, with pump percentages from 6 to 16% being found with a 10% target. Factors affecting the final pump percentage can be divided into three large categories: brine, meat, and equipment. Here is a quick review each:

• • Brine. Ingredients, the ingredient concentration, and brine temperature are all important factors affecting variation. Most brines contain salt and phosphate. The amount of each ingredient used can affect brine pickup. Brine temperature should be as low as possible. Warm brines will run out of a product.

• • Meat. Differences in meat can cause large variations in brine pickup. These differences include pH, composition, temperature, previous storage conditions, species, and cut. Meat with a low pH will not accept brine very well, PSE pork should not be pumped. Higher fat cuts will also not accept brine as well as leaner cuts, as protein is required to bind water. Do not expect the same brine pickup from bellies as hams at the same equipment settings. Warm meat will not accept brine well. Previously frozen meat will not pump the same as fresh meat, in addition, meat that has been stored for an extended period may have a different brine pickup than meat that is directly out of carcass chill. Also do not expect beef and pork to pickup the same amount of brine at the same injector settings. If you are going to pump beef and pork on the same machine you should run trials to determine the appropriate settings for each.

• • Equipment. Differences in equipment can be a frustrating cause of variation in pump percentages. Pump percentages are typically controlled three ways, by altering the injection pressure, needle dwell time in the product, and the speed the product moves through the injector. Differences in pressure can be do to loading, as meat moves through some injectors with a single pump and manifold the needles in the meat will have more resistance than needles that are not in the meat. As the brined moves more easily through the open needles, the needles in the meat will deliver less brine than anticipates. Some models of injector overcome this limitation with closer control of pressure to injector needles, however, this problem can also be minimized by making sure the injector is fully loaded so all the needles are in meat at all times. Injector needles that become clogged will also result in uneven distribution of brine; make sure that the filtering system of the pump is working properly to prevent this from happening.

There are essentially no differences in the actual mechanics and production of pumped, injected, basted, enhanced, and deep marinated meat, however, there may be labeling issues. The term “marinated” has a specific definition according to USDA as follows:

“MARINATED: To be labeled “marinated,” a product must use a marinade that is a mixture in which food is either soaked, massaged, tumbled, or injected in order to improve taste, tenderness, or other sensory attributes, such as color or juiciness. Time allotted in a marinade depends on many factors, including thickness and size of the meat and strength of the marinade. Marinade should be that amount necessary to affect the finished product, and limited to 10% pickup in red meat….”

If you want to produce an uncured red meat product with greater than a 10% pickup, it cannot be labeled simply as “marinated” but, must at least have the amount of added liquid declared. Following is the USDA language for adding water-based solutions to red meat (the bolding has been added to highlight the important parts of the regulation:

“WATER BASE SOLUTIONS IN RED MEAT IN MEAT PRODUCTS: Solutions intended to impart flavor (not extend the product) may be added in any amount to uncooked, cured and uncooked, uncured red meat products including those that have been chunked, ground, wafer sliced, etc., and formed/shaped.

For products marinated (i.e., soaked, steeped, massaged, tumbled, or injected in order to improve taste, texture, tenderness, or other sensory attributes, such as color or juiciness) and identified as “marinated,” the solution added is limited to 10 %. The qualifying statement must include the percentage of solution contained in the product, e.g., “Marinated with up to 8% of a Solution of Water, Salt, and Sugar.”

For all products, the qualifying statement must be at least one-fourth the size of the largest letter in the product name. If the ingredients of the solution accompany the qualifier, they must appear in print at least one-eighth the size of the largest letter in the product name. For uncooked products, the percent added substances for the label statement is determined by subtracting the fresh (green) weight of the article from the weight of the finished (total) product, i.e., after injecting, marinating, etc., dividing by the weight of the fresh article, and multiplying by 100.

• • Inadequate protein extraction. In order for protein to be the continuous phase, and coat the fat particles, it must be solubized into a solution. The most important meat proteins, myosin and actin, are solublized, or able to coat fat and bind water when exposed to salt. In addition, some mechanical energy must be present to extract the proteins. If the level of salt is inadequate, the protein or lean source is not adequately chopped or ground prior to the addition of the fat source, or the protein has been otherwise altered due to previous cooking, such as rework, the proteins will be unable to adequately coat the fat particles, resulting in a failed emulsion. If you have emulsions that are failing and you have not excessively chopped the fat ingredients or added large amount of high collagen lean, check to make sure that the correct amount of salt has been added, and the lean portion has had adequate mixing and chopping time.

Emulsifications can be difficult to produce, and when they fail, the result can be a complete loss of product and a lot of potential rework. Therefore, planning, process control, and ingredient quality control are essential to the production of good emulsified products. Emulsions are made up of two phases, continuous and discontinuous, with the emulsion taking on the characteristics of the continuous phase. For meat emulsions, the continuous phase is made up of protein and the discontinuous phase is fat, therefore a meat emulsion should have the characteristics of meat. If for some reason, the emulsion becomes “inverted” and fat becomes the continuous phase protein become discontinuous, the emulsion will take on the characteristics of fat and will be similar to a stick of lard.

Three common causes of emulsion failure are:

1. Excessive chopping of the fatty ingredients
2. Too much collagen in the lean meat ingredients
3. Inadequate protein extraction

• • Excessive chopping of fatty ingredients. For fat to be the discontinuous phase, it must be surrounded by protein, essentially holding small particles of fat in a matrix of protein. Therefore, when chopping the fatty ingredients, size does matter. Larger fat particles have, in total, much less surface area than smaller. For example if you compare a basketball to 30 golf balls, both will fill about the same volume of space, but the golf balls will have much, much more surface. When the fat particles become too small there is not enough protein to coat the surface of the fat, allowing the fat to become the continuous phase, and causing the emulsion to fail. Reduce excessive chopping of fat requires that the fat portion of the emulsion be initially ground separately from the lean tissue and added to the chopper or emulsifier later during processing. In general the lean meat ingredients should be well ground and chopped before the fatter ingredients are added.

• • Too much collagen. Collagen is a connective tissue protein abundantly found in meat, and is in especially higher amounts in meat such as shanks, cheek meats, and organ meats. Collagen protein does not do a good job of coating fat particles. Collagen does not go “into solution” in a meat emulsion and does not work to stabilize the emulsion. Collagen is essentially just along for the ride in an emulsion, therefore if a large portion of the meat source is high in collagen it is easier for the fat particles to become the continuous phase. In general, the amount of high collagen meats, such as shank and cheek should be limited to 5-10% of any emulsion.

• • Inadequate protein extraction. In order for protein to be the continuous phase, and coat the fat particles, it must be solubized into a solution. The most important meat proteins, myosin and actin, are solublized, or able to coat fat and bind water when exposed to salt. In addition, some mechanical energy must be present to extract the proteins. If the level of salt is inadequate, the protein or lean source is not adequately chopped or ground prior to the addition of the fat source, or the protein has been otherwise altered due to previous cooking, such as rework, the proteins will be unable to adequately coat the fat particles, resulting in a failed emulsion. If you have emulsions that are failing and you have not excessively chopped the fat ingredients or added large amount of high collagen lean, check to make sure that the correct amount of salt has been added, and the lean portion has had adequate mixing and chopping time.

Iridescence in beef is the rainbow-like appearance on the surface, caused by light diffracting off smooth muscle fibers, similar to how a prism works. It is more noticeable in certain cuts, such as the semitendinosus (eye of the round), and is influenced by factors like the angle of the cut, surface texture, added ingredients, and cooking methods.

For example, slicing meat perpendicular to the muscle fibers, smoother surfaces, or adding moisture-retaining solutions like phosphates can enhance iridescence. Cooking to lower temperatures and creating rougher surface textures may help reduce its occurrence. Importantly, iridescence is a natural phenomenon and does not indicate spoilage or reduced quality. If it becomes a significant issue, processors may need to review suppliers, ingredients, or processes to identify contributing factors.

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DFD meat appears darker in color than normal meat and holds greater spoilage potential due to its pH level of 6.0 or above.

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PSE meat appears lighter in color with a soft and mushy texture; high levels of fluid lead to excessive release of moisture sometimes causing a wet surface appearance.

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Unlabeled allergens are one of the leading causes of food recalls in the U.S., and most could be prevented with a proper allergen control plan. Allergens can also cause severe health problems for sensitive individuals, making control a critical part of any food safety program.

The eight major allergenic foods, often referred to as the Big-9, comprise milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, and sesame.  In 2021 sesame was added as an important allergen to control.  Understanding allergens is the first step in developing a control plan and the University of Nebraska’s Food Allergy Research and Resource Program provides an excellent overview of the most common food allergens that must be managed.

Fresh meat and poultry alone are not considered allergens. However, even if you only produce fresh meat, you should have a Standard Operating Procedure (SOP) acknowledging allergen risks. Allergens can enter a facility through employee lunches, packaging materials, or outside sources.

The USDA FSIS has a compliance document about allergen control.  The document is comprehensive, however, has not been updated since 2015.

The allergen plan should involve multiple departments, including quality control, production management, purchasing, and maintenance—anyone who influences production.

Allergens can enter a facility through incoming ingredients or supplies used in processing. This is especially common in further processed meats like sausage, cured meats, and smoked products. Processors should work closely with suppliers to ensure allergens are clearly listed and that any formulation changes are communicated. Some recalls have occurred because a supplier changed an ingredient without notifying customers.

Once allergens are identified, they must be properly labeled and stored to prevent accidental use. Best practices include:

• Separate storage areas for allergenic ingredients
• Brightly colored signs (30 cm or larger) to mark allergen-containing ingredients and equipment
• Moving allergen signs from storage to equipment to finished product to ensure proper tracking during production

Sanitation Standard Operating Procedures (SSOPs) should be updated to address allergen-containing equipment. Even trace amounts of allergens can cause health issues, so thorough cleaning is essential.

• Schedule allergen-containing products at the end of the day to avoid mid-shift cleanups.
• Ensure proper sanitation before switching to non-allergenic products.
• Prevent cross-contamination by enforcing strict cleaning protocols.

Labels must clearly state any allergens present in the product. Regulations dictate how allergens must be listed, so processors should ensure compliance. Any label changes should be reviewed by production, purchasing, and quality control to confirm accuracy.

Allergens are classified as chemical hazards in a hazard analysis. While HACCP plans typically do not control allergens directly, a comprehensive allergen control plan should be in place.

Record-keeping is essential for tracking allergen management. Common records include:

• Receiving logs (indicating allergen presence)
• Storage records
• Sanitation records
• Final product labeling checks

Plant management must actively promote sanitation as a priority and maintain enthusiasm for food safety. Employees should understand that proper sanitation leads to higher quality and safer meat products, improving company profitability. Additionally, it is essential for at least one member of management to have sanitation expertise and stay updated on industry developments by periodically attending workshops and trainings.  Ongoing outbreaks of Listeria monocytogenes in multiple different foods reinforces the need for high level sanitation.

People learn best through different formats—reading, listening, seeing, or doing. A mix of classroom instruction, hands-on training, videos with discussions, and practical demonstrations in production areas enhances learning.  Short, frequent training sessions (~1 hour) are more effective than a single long session that exceeds an hour.

Sanitation procedures can become routine, leading to complacency. Ongoing training helps reinforce proper cleaning practices. Monthly meetings to discuss equipment changes, sanitation-related noncompliance records, or updates to SSOPs ensure employees remain informed and engaged.

Each employee with sanitation responsibilities should have a concise and easy-to-understand handbook outlining essential cleaning and sanitizing procedures. The handbook should be covered in initial training and serve as an ongoing reference. Some companies require employees to read the handbook and pass a test, which may be tied to employment or incentives like raises.  The sanitation handbook should be based on companies Sanitation Standard Operating Procedures (SSOP’s).

Feedback should flow in both directions—employees should be encouraged to report equipment defects, hard-to-clean surfaces, water pressure issues, or potential biofilm buildup. Simple reporting methods and rewards for identifying sanitation challenges improve cleanliness. Additionally, management should provide feedback on employee efficiency using tools like bacterial swabbing, hydrogen peroxide testing, or organic matter detection systems. Positive reinforcement for proper sanitation practices boosts motivation and effectiveness.

Packing plants see the highest injury rates among meat processing facilities, but other types of plants also face risks. The most frequent injuries include:

• Sprains and strains
• Cuts
• Bruises and back strains

Amputations (rare but serious)

Worker safety is a shared responsibility between employees and plant management.

• Workers should use personal safety equipment—even if it feels heavy or cumbersome. Injuries often happen when safety gear is ignored. Advances in lighter, more flexible safety equipment have improved compliance.
• Processors should provide proper training to ensure workers use safety techniques correctly and follow established work procedures.

Several important practices help reduce workplace injuries:

• Proper techniques: Employees who use equipment correctly and follow safe cutting and lifting methods are less likely to get injured.
• Effective training: Workers should be given time to learn their roles under supervision to minimize accidents.
• Employee feedback: Workers often identify safety risks and can suggest improvements, making plants safer.

Regular equipment maintenance: Ensuring machinery functions properly prevents workers from attempting risky repairs during production. Making sure safety features on equipment are working properly is essential for meat plants.

OSHA and the American Meat Institute (AMI) provide safety guidelines for meat processors.

• Visit OSHA’s meatpacking safety page

Call OSHA at 1-800-321-OSHA (6742)

Most meat formers have three unique parts:

1. Pressure System – Pushes raw ingredients into the mold (mechanical or hydraulic).
2. Forming Mold or Extruder – Shapes the product (patty molds for burgers, extruders for meatballs).
3. Strike Plate – Forces formed meat out of the mold (not needed for extruded products).

Some formers also include interleavers (for paper separation) and common processing components like hoppers, conveyors, check scales, and microprocessors.

Operator training is one of the most cost-effective maintenance strategies. Many mechanical breakdowns and wear issues can be detected early if operators are properly trained.  Employees must be empowered to stop production to fix problems without management interference.

Operators should be aware of:

• Unusual sounds – Metal striking metal or whining motors indicate maintenance is needed.
• Product quality – Malformed patties or nuggets often signal machine issues.
• Equipment matching – Push and feed parts may need adjustment when switching molds.

Lubrication schedules – Some formers require daily lubrication with edible grease, while others need less frequent maintenance.

Improper stroke length or mold positioning can cause:

• Excessive wear on strike plates and push arms.
• Stress on motors and hydraulics, leading to premature failure.
  Regular checks and adjustments help prevent these issues.

Equipment condition changes over time and it is important to periodically inspect, maintain, or replace some components.  Burrs or gouges can develop on forming molds or strike plates, leading to inconsistent product and increased strain on the machine.  Minor burrs can be corrected by grinding the mold or strike plate back to its original shape. Severely damaged molds should be replaced to maintain product quality and equipment efficiency.

Cross contamination in meat processing facilities refers to the unintentional transfer of harmful microorganisms, pathogens, or foreign substances such as allergens from one surface, object, or product to another, potentially compromising food safety. This can occur through direct contact like raw meat touching cooked meat, indirect contact such as contaminated equipment, utensils, or hands, or environmental factors including airborne particles or water droplets.

Processors working with beef, pork, and lamb should keep products segregated as much as possible until required for processing. Traditionally, beef is handled first, followed by lamb, with pork last to reduce potential trichinae spread. However, data from the Centers for Disease Control show trichinae levels of domestic pork are extremely low, making this order of handling less critical than in the past.

A great deal of emphasis should be placed on correctly labeling products where cross contamination is a possible risk. If equipment cannot be completely cleaned between batches of different species, it is advisable to include the previous species on the label. For example, when switching from beef to pork franks, listing beef as an ingredient on the pork franks label eliminates the need for complete equipment cleaning between batches.

Many recalls result from the presence of unlabeled ingredients or allergens. If multiple products are being produced, it is important to keep ingredients and products separate and clearly labeled. Accidentally adding the wrong meat or other ingredients to a mixer could result in a mislabeled product.

Equipment can transfer allergens or unlabeled ingredients between batches. For example, if a sausage containing soy is produced followed by one without soy in the same equipment, residual soy may contaminate the second product, potentially leading to a recall.

Ingredients and products should be kept separate and clearly labeled. Ensuring accurate batching and cleaning reduces the risk of unlabeled allergens making their way into products. Additionally, taking the time to construct thoughtful production schedules and carefully laying out plans for processing species and ingredients in a logical order can reduce the risk of cross contamination and save time and money in cleaning and potential recalls.

A batch containing rework must list all ingredients from the reworked product. Additionally, microbial contamination in rework can spread to all products containing it, increasing recall risks.

If a reworked product is contaminated, all products containing the rework would be suspect and subject to recall. “Breaking the chain” of rework periodically helps limit the amount of product exposed to a recall.