1. Introduction
Food processing equipment refers to the machinery and surfaces that move, transform, and package foods. Devices range from intake bins, pumps, mixers, cutters, and heat exchangers to conveyors, fillers, and cleaning systems. These tools enable safety, consistency, and shelf life at scale by performing bulk operations such as heating, cooling, mixing, grinding, fermenting, drying, and forming. Because foods contact large areas of different food contact materials including metals, polymers, elastomers, coatings, and lubricants—often repeatedly and under heat, pressure, and shear—this stage is as consequential for hygiene and chemical safety as packaging (FPF reported).[1][2]
Controlling migration of chemicals from food contact materials (FCMs) is a well-established issue for packaging.[3][4] Less public attention has been paid to the equally extensive surfaces that foods encounter before they reach the package.
A universally accepted definition of “ultra-processed food” (UPF) or a protocol for classifying which foods are ultra-processed has not been universally standardized, but the term is usually applied to a category of food products that have undergone extensive industrial processing, and often contain multiple ingredients and additives that one wouldn’t typically find in a home kitchen or traditional cooking. Many UPFs undergo numerous operations (grinding, extrusion, high shear mixing, hot fill) and spend longer in contact with machinery. These conditions of, high temperature, shear, and large surface area contact, in conjunction with often fatty foods, can increase the likelihood and extent of equipment-related chemical migration (FPF reported), making equipment a relevant but understudied chemical exposure pathway in food safety discussions (FPF reported).
2. Roles of Food Processing Equipment
Food processing equipment turns raw ingredients into finished food products, including through cleaning, size reduction, separation, mixing, texturing, heating/cooling, shaping, and, finally, preserving and packaging. The sections below outline the main equipment types used at each stage, what they do, and why they matter for product creation.
Ingredient processing
- Cereal grain milling: Grains are cleaned, tempered, and passed through roller mills and sifters to separate endosperm from bran and germ.[5] This yields refined flour with improved baking performance and shelf stability, but reduced fiber and micronutrients relative to whole grain.[6]
- Oilseed crushing & refining: Seeds (soy, rapeseed, sunflower, etc.) are dehulled, flaked, conditioned, and pressed or solvent-extracted. The crude oil is then refined, bleached, and deodorized (RBD) to remove phospholipids, free fatty acids, pigments, and odors, producing shelf-stable oils that can be purchased in any grocery store.[7][8][9]
- Fractionation and isolation: This involves separating specific components, such as proteins or starches, from their original food sources. Machines like centrifuges and separators are used to isolate these components, which are then recombined in various forms.[10][11]
Formulation, mixing, and shaping
- High-shear mixers and high-pressure homogenizers: These machines are essential in creating the homogenous mixtures that define many UPFs. High-shear mixers blend various ingredients, including emulsifiers and stabilizers, ensuring a consistent texture and taste. High-pressure homogenizers force pumpable foods through a narrow valve at very high pressure to break droplets and particles to sub-micron sizes, creating smooth, stable emulsions and dispersions used in dairy and plant-based beverages, dressings and sauces, creamers, desserts, flavor emulsions, and protein/fiber suspensions.[12]
- Extruders: Extruders blend and cook food ingredients before forcing them through a die to create a specific shape.[13] At the same time, extrusion can texturize and sterilize the food using high temperatures.[14] Products like breakfast cereals, snack puffs, and certain types of pasta get their distinct shapes from extruders.[15]
- Spray dryers: Spray dryers rapidly evaporate liquids, creating fine powders like powdered milk or instant coffee, that can be easily rehydrated or used in dry mixes.[16][17]
- Texturizers: Texturizers are used to disperse and integrate hydrocolloid gelling agents into food matrices. These agents are added to mimic natural foods with textures such as chewy, crunchy, or creamy.[18]
- Molding and enrobing machines: These machines are used to shape foods into bars, nuggets, or patties and then coat them with layers of chocolate, batter, or seasoning, creating a uniform product.[19][20]
Preservation and packaging
- Aseptic processing and packaging: Aseptic processing involves sterilizing food products and packaging them in a sterile environment, ensuring a long shelf life without the need for refrigeration.[21] It is widely applied in the food industry, including for dairy products, juices, baby foods, and infant formula, which are briefly heated to 135-150 C to kill off bacteria before being rapidly cooled and sealed. This ultra-high temperature treatment can increase the shelf life of liquid products from days to months or even years.[22]
- Modified atmosphere packaging (MAP): MAP technology involves replacing the air inside a package with a gas mixture that extends the product’s shelf life by slowing down spoilage. This is common in the packaging of snacks and baked goods as well as some fresh produce.[23]
3. Contamination pathways
Contaminants can enter food from processing equipment through several distinct mechanisms that depend on the material, product, temperature, time, and mechanical stress. Beyond simple transfer from intact surfaces, the dynamic conditions of the processing environment can mobilize metals, additives, lubricants, and degradation products. The pathways below summarize the most common routes observed in industrial settings and documented in the literature.
Chemical release
Aggressive conditions from acidic, high salt, etc. foods like tomato sauce or high fat content foods (milk, dairy, oils) accelerate the release of chemicals from food processing equipment. Metallic elements and ions from metals, for example, can migrate due to acidic foods. A laboratory study of tomato products observed a 26-‑fold increases in nickel concentrations after six hours of cooking at 85 °C.[24] Meanwhile, lipophilic plasticizers such as di‑(2‑ethylhexyl) phthalate (DEHP, CAS 117-81-7) diffuse from PVC hoses into high fat foods like milk.[25] DEHP and other phthalates have been measured in milk samples from Korea [26], Turkey [27], Europe [28], and the US [29] (FPF reported), all linked to processing equipment.
Mechanical, thermal, and chemical degradation
Mechanical forces during food processing cause the abrasion and release of small plastic particles, commonly referred to as micro- and nanoplastics, when reaching sizes < 1 mm and 1 nm, respectively. Initial studies indicate that UPFs contain significantly more MNPs than less-processed products, and plastic processing equipment is a potential source.[30][31] And those plastic particles can release their contained chemicals into foods and humans.[32] Other equipment stressors like repeated exposure to heat, steam, UV, and oxidizing chemistries can alter polymers, elastomers, and coatings at the surface—breaking bonds, generating wear debris, and forming smaller, more mobile molecules that migrate into food. For example, repeated steam sterilization can break down silicone seals, releasing siloxanes, and high energy‑ UV or oxidizing agents can degrade polytetrafluoroethylene (PTFE) coatings, producing perfluoroalkyl acids (PFAAs), which are a type of PFAS.[33][34][35]
Lubricant carry‑over
Lubricants reduce friction and heat in bearings, chains, gearboxes, pumps, and seal assemblies adjacent to product contact areas. Because these points often operate above the line or inside wetted housings, with potential for misting, seal leaks, and over-application, small amounts are likely to enter food (even products meeting common standard NSF H1 are permitted to release up to 10 mg/kg into food due to incidental contact).[36][37]
Cleaning and sanitizer residues
Routine cleaning and sanitizing rely on oxidizers, quaternary ammonium compounds, acids/alkalis, and surfactants to control microbes. When rinsing, segregation, or clean-in-place validation fails, these agents (or their by-products) can get onto the product or desorb from equipment surfaces.[38][39] In March 2025, 212 tons of liquid egg product were recalled in the U.S. after bleach was inadvertently introduced during cleaning operations.[40]
4. Chemicals of concern
A large variety of chemicals have the potential to transfer into food products during food processing steps. The FCCmigex database documents over 2,000 chemicals detected to migrate into foods from food processing, cookware, and packaging materials, and estimates of additional non-intentionally substances (NIAS) that may be present in materials go up to 100,000.[41] A few chemical groups that have been relatively well studied when it comes to exposure from processing equipment include:
Metals in food processing equipment
- Nickel & chromium are alloying elements in stainless steels that improve corrosion resistance, hardness, and cleanability. Ions can be released from wetted stainless steel parts under acidic/salty conditions, long contact times, high temperature, or damaged surfaces. Nickel (Ni, CAS 7440-02-0) is a potent contact allergen and suspected to be carcinogenic, as is chromium (VI) (CAS 18540-29-9). Though chromium transfer is not typical in food contact steels but may arise from improper surface treatments.[24][42][43][44]
- Aluminum is used for lightweight heat transfer components and trays. Like with Nickel and Chromium, ion migration can come from uncoated aluminum in contact with acidic/salty foods or at elevated temperatures. It contributes to off flavors and discoloration in the foods and chronic exposure shows links to neurotoxicity.[45][46]
Additives in food processing equipment
- Phthalate and non-‑phthalate plasticizers (DEHP, DINP, DINCH, etc.) provide flexibility and softness to plastic hoses, gaskets, and some rubber parts used for pumping/transfer and seals. The plasticizers can transfer into high-fat foods (milk, cheese, sauces, oils) during pumping/holding, especially at warm temperatures, with elevated migration from aged or highly plasticized tubing and seals.[25][47] Some phthalates are reprotoxic and endocrine disrupting, and regulations on phthalates in food contact are increasing (FPF reported also here).[48]
- Antioxidants such as butylated hydroxytoluene (BHT, CAS 128-37-0) and Irganox 1010 (CAS 6683-19-8) are used to stabilize rubbers and polyolefin plastics used in seals, hoses, and scraper blades by preventing oxidative polymer breakdown. As with other forms of chemical release, it is increased with temperature or with fatty foods. Some antioxidants may create off-flavors, and there are toxicological concerns for specific antioxidants at high exposure. Some have set specific migration limits (SMLs) in food contact regulations or are otherwise monitored.[49][50]
Process chemicals
- PFAS (per- and polyfluoroalkyl substances) are used as additives or coatings to provide non-stick/low-friction surfaces. Residual monomers/oligomers and degradation products from fluoropolymer coatings can transfer into food under heat, UV, or oxidative stress. As can particles from worn non-stick layers. PFAS are subject to proposed REACH restrictions in the EU, including uses in food processing equipment.[51][52]
- Mineral‑oil hydrocarbons (MOSH/MOAH) lubricate bearings, chains, gearboxes and are found in hydraulic fluids for actuators (FPF reported).[53] There can be incidental contact with MOSH/MOAH via seal leaks, misting, drips, or over-application near production zones as well as cross-contamination during maintenance or deposition on belts or fillers. MOSH accumulates in human tissues, and MOAH (≥3 rings) are potentially carcinogenic.[54]
- Chlorate can be used in fluids to clean and disinfect processing lines, surfaces, and utensils to control microbial hazards. It can get into food when inadequate rinsing occurs after cleaning.[55][56] Chlorate can impair iodine uptake and thyroid function.[57]
5. Regulation and Actions
Food‐contact rules that apply to packaging generally also govern the ‘wetted’ parts of processing equipment – those that may touch the food. In the EU, Regulation (EC) No 1935/2004 sets basic safety guidance, while plastics components are further covered by Commission Regulation (EU) 10/2011 (which applies to materials “intended to come into contact with food” or that “can reasonably be expected” to do so).[58] The Machinery Regulation (EU) 2023/1230 adds design-stage duties for safe and hygienic machinery placed on the market. In the U.S., the FSMA Preventive Controls rule requires facilities to analyze and control process-related chemical hazards, with specific provisions for lubricants in 21 CFR 178.3570.[59]
While many food brands publicize improvements in the chemical safety of their packaging, fewer make commitments related to processing equipment (FPF reported; see also the Brand and Retailer Initiatives Database). However, discovered incidents of contamination from processing equipment have led to public health scandals and reputational damage to brands. For example, following a 2021 report on phthalates in US dairy products, US organic food brand Annie’s committed to working with “trusted suppliers to eliminate ortho-phthalates that may be present in the packaging materials and food processing equipment that produces the cheese and cheese powder in our macaroni and cheese” (FPF reported). The FCCprio List provides a prioritized list of food contact chemicals to phase out and avoid in processing equipment and packaging based on their known hazard properties and exposure potential.
6. Conclusion
Food processing equipment is an often overlooked pathway where chemicals can migrate into foods. Importantly, the extreme physical conditions applied during some processing steps and the prolonged contact with highly chemically complex, non-inert equipment typical for many modern food products can increase chemical migration. Documented pathways include leaching metals, diffusion of plasticizers and lubricants, sanitizer carry-over, abrasion-derived microplastics, and degradation products such as siloxanes and PFAAs. Compared with packaging, this area has historically received less attention, but scrutiny and data on real-world contributions are steadily increasing.
7. References
[1] Pakdel, M.; et al. (2023). “A Review of Food Contaminants and Their Pathways Within Food Processing Facilities Using Open Food Processing Equipment.” Journal of Food Protection. DOI: 10.1016/j.jfp.2023.100184
[2] Rather, I.A.; et al. (2017). “The Sources of Chemical Contaminants in Food and Their Health Implications.” Frontiers in Pharmacology. DOI: 10.3389/fphar.2017.00830
[3] Muncke, J.; et al. (2020). “Impacts of food contact chemicals on human health: a consensus statement.” Environmental Health. DOI: 10.1186/s12940-020-0572-5
[4] Geueke, B.; et al. (2022). “Systematic Evidence on migrating and extractable Food Contact Chemicals: Most Chemicals detected in Food Contact Materials are not listed for use.” Critical Reviews in Food Science and Nutrition. DOI: 10.1080/10408398.2022.2067828
[5] North American Millers’ Association. (n.d.). “What is milling?” [Accessed August 30, 2025].
[6] The Nutrition Source. (n.d.). “Whole Grains.” Harvard T.H. Chan School of Public Health. [Accessed August 30, 2025].
[7] Alfa Laval. (n.d.). “Edible Oil Refining Process Systems.” (pdf). [Accessed August 30, 2025].
[8] Penn State Extension. (August 19, 2025). “Processing edible oils.” [Accessed August 30, 2025].
[9] Mr Johnson’s Farm. (July 11, 2023). “How canola oil is made | Tour of MSM millin in MAndrila NSW. Canola mill process.” YouTube.
[10] Berk, Zeki. (1992). “Chapter 6: Isolated Soybean Protein (ISP)”. In Technology of Production of Edible Flours and Protein Products from Soybeans (FAO Agricultural Services Bulletin No. 97). Food and Agriculture Organization of the United Nations. ISBN 92-5-103118-5. [Accessed August 30, 2025].
[11] Kornet, R.; et al. (2022). “Optimizing pea protein fractionation to yield protein fractions with a high foaming and emulsifying capacity.” Food Hydrocolloids. DOI: 10.1016/j.foodhyd.2021.107456
[12] SPXflow. (2008). “Homogenizing handbook: Processing of emulsions and diffusions.” (pdf).
[13] Brian Plattner. (2020). “Extrusion techniques for meat analogues.” Cerealsgrains.org. (pdf).
[14] Abilmazhinov, Y., et al. (2023). “A Review on The Improvement of Extruded Food Processing Equipment: Extrusion Cooking in Food Processing.” Food Science and Technology. DOI: 10.5327/fst.80621
[15] Tara McHugh. (July 1, 2017). “How extrusion shapes food processing.” Institute of Food Technologists.
[16] Tetra Pak. (n.d.). “Chapter 19: Milk and whey powdered ingredients.” Dairy Processing Handbook.
[17] GEA. (2012). “Milk powder handbook.“
[18] Saha, D. and Bhattacharya, S. (2010). “Hydrocolloids as thickening and gelling agents in food: a critical review.” Journal of Food Science and Technology. DOI: 10.1007/s13197-010-0162-6
[19] Ramana Sundara, Ángel Máñez and Josélio Vieira. (March 5, 2014). “Enrobing in the confectionary industry.” New Food.
[20] Marel. (n.d.) “Taking low-pressure forming up a level.”
[21] US Food and Drug Administration. (2005). “Aseptic processing and packaging for the food industry.”
[22] Oumar Fofana. (July 23, 2025). “Aseptic packaging: ensuring food safety and extending shelf life.” Packaging Gateway. [Accessed October 12, 2025].
[23] Claire Kolsch Sand. (May 1, 2016). “Modified atmosphere packaging expands.” Institute of Food Technologists.
[24] Kamerud, K.L; et al. (2013). “Stainless Steel Leaches Nickel and Chromium into Foods during Cooking.” Journal of Agricultural and Food Chemistry. DOI: 10.1021/jf402400v
[25] Pure Strategies. (2018). “Sources of phthalates in dairy farm equipment.” EcoCenter. (pdf). [Accessed August 29, 2025].
[26] Kim, M.; et al. “Determination of phthalates in raw bovine milk by gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS) and dietary intakes.” Food Additives and Contaminants: Part A. DOI: 10.1080/02652030802342471
[27] Korkmaz, S.D.; et al. (2023). “Migration Of Phthalates from Plastic Packages into Dairy Products.” Kafkas Universiti Veteriner Fakultesi Dergisi. DOI: 10.9775/kvfd.2023.29317 (pdf).
[28] European Food Safety Authority. (2019). “Update of the risk assessment of di-butylphthalate (DBP), butyl-benzyl-phthalate (BBP), bis(2-2 ethylhexyl)phthalate (DEHP), di-isononylphthalate (DINP) and di-isodecylphthalate (DIDP) for use in food contact materials.” EFSA Journal. DOI: 10.2903/j.efsa.2019.5838
[29] Serrano, S.E.; et al. (2014). “Phthalates and diet: a review of the food monitoring and epidemiology data.” Environmental Health. DOI: 10.1186/1476-069X-13-43
[30] Milne, M.H., et al. (2024). “Exposure of U.S. adults to microplastics from commonly-consumed proteins.” Environmental Pollution. DOI: 10.1016/j.envpol.2023.123233
[31] Zimmermann, L. et al. (2025). “Food contact articles as source of micro- and nanoplastics: a systematic evidence map.” npj Science of Food. DOI: 10.1038/s41538-025-00470-3
[32] Yu, Y. et al. (2024). “Various additive release from microplastics and their toxicity in aquatic environments.” Environmental Pollution. DOI: 10.1016/j.envpol.2023.123219
[33] Su, Y.; et al. (2022). “Steam disinfection releases micro(nano)plastics from silicone-rubber baby teats as examined by optical photothermal infrared microspectroscopy.” Nature Nanotechnology. DOI: 10.1038/s41565-021-00998-x
[34] Merkel, Stefan. (November 23, 2022). “BfR activities on silicone.” European Food Safety Authority. (pdf). [Accessed August 31, 2025].
[35] Schlummer, M.; et al. (2015). “Emission of perfluoroalkyl carboxylic acids (PFCA) from heated surfaces made of polytetrafluoroethylene (PTFE) applied in food contact materials and consumer products.” Chemosphere. DOI: 10.1016/j.chemosphere.2014.11.036
[36] NSF. (2021). “How Registrations Prove Lubricants Are Food Grade.” [Accessed August 29, 2025].
[37] EFSA Panel on Contaminants in the Food Chain (CONTAM), et al. (2023). “Update of the risk assessment of mineral oil hydrocarbons in food.” EFSA Journal. DOI: 10.2903/j.efsa.2023.8215
[38] US Food and Drug Administration. (August 26, 2014). “Validation of cleaning processes (7/93).” [Accessed October 14, 2025].
[39] EAS Consulting Group. (August 1, 2020). “Cleaning-In-Place (CIP) validation.” [Accessed October 14, 2025].
[40] US Food and Drug Administration. (2025). “Cargill Kitchen Solutions Recalls Liquid Egg Products Due to an Unapproved Substance.” [Accessed August 29, 2025]
[41] Grob, K., et al. (2006). “Food contamination with organic materials in perspective: packaging materials as the largest and least controlled source? A view focusing on the European situation.” Critical Reviews in Food Science and Nutrition. DOI:10.1080/10408390500295490
[42] European Committee for Food Contact Materials and Articles. (2024). “Metals and alloys used in food contact materials and articles: A technical guide for manufacturers and regulators, 2nd edition.” Council of Europe. (pdf). [Accessed October 13, 2025].
[43] European Chemicals Agency. (n.d.). “Chromium (VI) substance infocard.” [Accessed October 14, 2025].
[44] European Chemicals Agency (n.d.). “Nickel substance infocard.” [Accessed October 14, 2025].
[45] German Federal Institute for Risk Assessment. (2017). “Uncoated aluminium menu trays: First research results show high release of aluminium ions.” (pdf). [Accessed August 29, 2025].
[46] European Food Safety Authority. (2008). “Safety of aluminium from dietary intake – Scientific Opinion of the Panel on Food Additives, Flavourings, Processing Aids and Food Contact Materials (AFC).” EFSA Journal. DOI: 10.2903/j.efsa.2008.754
[47] Fierens, T., et al. (2013). “Transfer of eight phthalates through the milk chain — A case study.” Environment International. DOI: 10.1016/j.envint.2012.10.002
[48] Maffini, MV., et al. (2021). “The role of epidemiology in risk assessment: a case study of five ortho-phthalates.” Environmental Health. DOI: 10.1186/s12940-021-00799-8
[49] Lu, L.; et al. (2022). “Migration of antioxidants from food-contact rubber materials to food simulants.” Journal of Food Engineering. DOI: 10.1016/j.jfoodeng.2021.110904
[50] Maghsoud, Z., et al. (2017). “Effect of processing method on migration of antioxidant from HDPE packaging into a fatty food simulant in terms of crystallinity.” Packaging Technology and Science. DOI: 10.1002/pts.2359
[51] European Tyre & Rubber Manufacturers Association. (2023). “Of the impacts of a potential restriction of per-and polyfluoroalkyl substances (PFAS) on the tyre & rubber industry.” (pdf). [Accessed August 29, 2025].
[52] Phelps, D.W.; et al. (2024). “Per- and polyfluoroalkyl substances in food packaging: Migration, toxicity, and management strategies.” Environmental Science & Technology. DOI: 10.1021/acs.est.3c03702
[53] European Food Safety Authority. (2023). “Update of the risk assessment of mineral oil hydrocarbons in food.” EFSA Journal. DOI: 10.2903/j.efsa.2023.8215
[54] German Federal Institute for Risk Assessment. (July 31, 2023). “Questions and answers on mineral oil components in food.” [Accessed October 14, 2025].
[55] German Federal Institute for Risk Assessment. (July 9, 2025). “Chlorate in food.” (pdf). [Accessed August 29, 2025].
[56] European Food Safety Authority. (2015). “Risks for public health related to the presence of chlorate in food.” EFSA Journal. DOI: 10.2903/j.efsa.2015.4135
[57] Association of Organic Food Processors. (July 6, 2020). “Chlorate / perchlorate – residues.” (pdf). [Accessed October 14, 2025].
[58] European Commission. (n.d.). “Food safety legislation.” [Accessed August 31, 2025].
[59] US Food and Drug Administration. (n.d.). “FSMA Final Rule for Preventive Controls for Human Food.” [Accessed August 31, 2025].
