Physical Hazards in Ready-to-Eat Foods: Foreign Material Control Points Under SFCR and HACCP

In September 2026, Danone USA recalled its So Delicious Dairy Free Salted Caramel Cluster non-dairy frozen dessert because of the potential presence of foreign materials, such as small stones and other hard objects, in the cashew inclusions. No pathogen, no allergen, no chemical residue. Just hard fragments that should never have reached a spoon. It is the kind of recall that does not make headlines the way a Listeria outbreak does, and it is exactly the kind of hazard that many preventive control plans quietly under-manage.

Food safety programmes are built to fight what can make people sick: bacteria, viruses, parasites, allergens and toxins. Physical hazards, the stones, metal, glass, bone and plastic that can chip a tooth, cut a mouth or choke a child, often sit in the background of a hazard analysis, controlled by habit rather than by design. This article looks at how foreign material becomes a physical hazard, what the Safe Food for Canadians Regulations and HACCP actually require, and how to build controls that hold up to a CFIA or FDA inspection.

MFLRC helps food manufacturers, importers and co-packers in Canada and the United States build preventive control plans and HACCP systems that treat physical hazards with the same rigour as biological ones. The frozen-dessert recall is a useful reminder of why that matters.

Executive Summary

A physical hazard is any hard or sharp foreign object in food that can cause injury: stones, metal fragments, glass, hard plastic, bone, wood or personal items. Under the Safe Food for Canadians Regulations, a food business must identify and control physical hazards alongside biological and chemical hazards in its preventive control plan, and CFIA expects documented controls at each point where foreign material can enter. FDA takes the same position: its Compliance Policy Guide 555.425 treats hard or sharp objects between 7 mm and 25 mm in length as capable of rendering a ready-to-eat food adulterated, and 21 CFR 117 lists physical hazards among the hazards a preventive controls plan must address. The controls are well established, supplier assurance, incoming inspection, metal detection, X-ray, magnets, sieves and optical sorting, but they only work when they are designed into the plan, monitored and verified. The So Delicious recall shows what happens when a raw-material physical hazard is not caught before it reaches the consumer.

What counts as a physical hazard?

In short: a physical hazard is any foreign object in food, hard or sharp enough to cause injury if a consumer bites or swallows it. Unlike biological and chemical hazards, a physical hazard is usually visible and always unwanted, and it can enter at almost any stage from field to package. CFIA groups physical hazards by where they come from, which is the most useful way to think about controlling them.

Physical hazard	Typical source
Stones, rocks and dirt	Raw agricultural materials grown close to the soil, including nuts, grains, pulses and produce
Metal fragments, staples, nails	Worn or broken equipment, blades, screens, packaging and maintenance work
Glass and hard plastic	Containers, light fittings, instrument covers, utensils and packaging
Bone and shell fragments	Meat, poultry and seafood ingredients
Wood splinters and flaking paint	Pallets, crates and overhead structures
Personal items	Jewellery, buttons and other items from improper handling practices

CFIA's reference database for hazard identification lists these sources in detail. The pattern that matters for control is clear: many of the most common physical hazards, especially stones in nuts and produce, arrive with the raw material, not the process. That is precisely how the cashew inclusions in the So Delicious recall carried stones into a finished frozen dessert.

Why physical hazards get under-controlled

Why it matters: physical hazards rarely cause the mass-illness outbreaks that drive recalls into the news, so they attract less attention in a hazard analysis. That is a mistake. A single hard object can injure a consumer, trigger a recall, and expose a documentation gap that an inspector will follow into the rest of your plan. Under-controlling physical hazards is not a smaller risk than a pathogen; it is a different risk with the same regulatory consequences.

Three habits drive the gap. First, physical hazards are treated as a housekeeping matter rather than a documented hazard with monitored controls. Second, the plan leans on a single end-of-line detector, usually a metal detector, and assumes it catches everything, when stones, glass and plastic are invisible to it. Third, raw-material physical hazards are assumed to be the supplier's problem, with no incoming verification. Each of these leaves a food ready to be recalled for exactly the reason So Delicious was.

What the SFCR and HACCP require

What to do: identify physical hazards explicitly in your hazard analysis, then control them with documented, monitored measures. The Safe Food for Canadians Regulations require a licence holder to identify the biological, chemical and physical hazards that present a risk of contamination, and to prevent, eliminate or reduce them to an acceptable level through the preventive control plan. Physical hazards are named in the regulation, not optional.

The SFCR preventive control plan is Canada's expression of HACCP. Under both, you conduct a hazard analysis, determine where physical hazards can be controlled, set critical control points and critical limits where needed, monitor them, and verify the whole system works. CFIA's guidance on incoming ingredients and materials sets the expectation for the supply side: sourcing controls, letters of guarantee or certificates of analysis, and receiving inspection that can reject contaminated material. A physical-hazard control programme that only starts at the metal detector is only half a programme.

For companies exporting to the United States, the requirement is parallel. 21 CFR Part 117 defines a hazard as any biological, chemical or physical agent with the potential to cause illness or injury, and a food facility must evaluate physical hazards in its hazard analysis. The FDA position on when a foreign object becomes a legal problem is set out next.

The size that turns an object into a hazard

Why it matters: not every speck of foreign material is a regulated hazard, but the threshold is lower than many producers assume. FDA's Compliance Policy Guide 555.425 states that a hard or sharp foreign object measuring between 7 mm and 25 mm in length can render a food adulterated when the food is ready-to-eat or requires only minimal preparation, and the threshold is stricter for foods intended for infants and other special-risk groups. A small stone in a frozen dessert sits squarely inside that range.

Health Canada and CFIA take a comparable view: physical contaminants large or hard enough to injure are treated as a health risk, with tighter expectations for foods aimed at vulnerable groups such as infants. The practical lesson is that ready-to-eat products carry the highest exposure, because there is no cooking, washing or sorting step left for the consumer to catch what the process missed. Frozen desserts, snack bars, ready meals and confectionery all fall into this high-exposure category.

Where foreign material enters, and where to control it

What to do: map every point where foreign material can enter, then place a control at the earliest effective point and a detection step near the end. No single technology catches every physical hazard, so a layered programme is the only reliable design. The table below pairs common entry points with the controls that address them.

Entry point	Primary controls
Raw materials and ingredients	Supplier approval, certificates of analysis or letters of guarantee, specifications, incoming inspection, sieving or sifting, destoning, optical sorting
Processing equipment	Preventive maintenance, blade and screen inspection, equipment condition checks, in-line magnets
Packaging and containers	Glass and brittle-plastic register, packaging inspection, controlled use of glass in production areas
People and environment	Jewellery and personal-item policies, no-glass rules, control of overhead structures and flaking paint, pallet and crate condition
Finished product	Metal detection, X-ray inspection, final visual inspection, reject verification and record keeping

Metal detection catches ferrous, non-ferrous and stainless metal, but not stone, glass or plastic. X-ray inspection can detect dense foreign objects including stone, glass and some plastics, which is why it is increasingly the control of choice for products with raw agricultural inclusions like nuts. Magnets, sieves, filters, destoners and optical sorters each remove specific hazards earlier in the process. The right combination depends on your product and your raw materials, which is exactly what a hazard analysis is for.

The supplier side deserves particular attention for products with nut, grain, pulse or produce inclusions. As we have covered in our work on low-moisture food controls, the raw material is often where the hazard is born; the same is true for stones in nuts. A certificate of analysis that never mentions foreign material, and a receiving process that never checks for it, is a documented gap waiting to be found.

Foreign material control checklist

Use this checklist to test whether your preventive control plan treats physical hazards as seriously as biological ones. Every item maps to an expectation under the SFCR, HACCP or FDA preventive controls.

Physical hazards are identified explicitly in your hazard analysis, by type and by source, not folded into a general sanitation note.
Raw materials with a known physical-hazard risk (nuts, grains, pulses, produce, meat, seafood) have specifications that address foreign material.
Supplier approval includes letters of guarantee or certificates of analysis that cover physical hazards, and incoming inspection can reject contaminated material.
Early-process controls (sieves, sifters, destoners, magnets, optical sorters) are matched to the hazards your raw materials carry.
A final detection step (metal detection, X-ray, or both) is validated for your product, with defined critical limits and reject verification.
You do not rely on metal detection alone for stone, glass or plastic hazards.
A glass and brittle-plastic register is maintained, with breakage procedures.
Personal-item and jewellery policies are documented and enforced in production areas.
Monitoring records show detectors and controls are checked at defined frequencies, with corrective action when they fail.
Verification, including detector challenge tests and record review, confirms the system works.
A recall and traceability procedure can act quickly if a physical hazard reaches the market.

Common mistakes with physical hazards

Treating physical hazards as housekeeping. If foreign material is controlled by habit and cleaning rather than by a documented, monitored control, it will not survive an inspection or a recall investigation.

Relying on one metal detector. A single end-of-line detector cannot see stone, glass or most plastic, and it does nothing about a hazard that has already injured the product's reputation.

Ignoring the raw-material source. Most physical-hazard recalls, including the So Delicious stones, trace to an ingredient, not the process. No supplier control means no early warning.

Skipping detector challenge tests. A metal detector or X-ray unit that is never challenged with test pieces is an assumption, not a control. Verification is what turns equipment into a critical control point.

Forgetting special-risk groups. Foods for infants and young children carry a stricter foreign-material expectation. A control designed for a general product may not be adequate for a children's line.

Frequently asked questions

What is a physical hazard in food?

A physical hazard is any foreign object in food that can cause injury if bitten or swallowed, such as a stone, metal fragment, piece of glass, hard plastic, bone, wood splinter or personal item. It is one of the three hazard categories, alongside biological and chemical hazards, that a hazard analysis must address under both the Safe Food for Canadians Regulations and HACCP.

Are physical hazards covered by the Safe Food for Canadians Regulations?

Yes. The SFCR requires a licence holder to identify the biological, chemical and physical hazards that present a risk of contamination and to control them through a preventive control plan. Physical hazards are named explicitly. A plan that only addresses pathogens and allergens does not meet the regulation.

How big does a foreign object have to be to make food adulterated?

Under FDA Compliance Policy Guide 555.425, a hard or sharp foreign object measuring between 7 mm and 25 mm in length can render a ready-to-eat food adulterated. Objects smaller than 7 mm can still be hazards for infants and other special-risk groups. Health Canada and CFIA apply a comparable risk-based view, with stricter expectations for foods intended for vulnerable populations.

Does a metal detector control all physical hazards?

No. A metal detector detects ferrous, non-ferrous and stainless metal, but it cannot see stone, glass or most plastics. Products with raw agricultural inclusions such as nuts often need X-ray inspection, which can detect dense objects including stone and glass, along with earlier controls like destoners, sieves and optical sorters. Relying on metal detection alone is a common and serious gap.

Where do most physical hazards come from?

Most physical-hazard recalls trace back to raw materials rather than the process. Stones arrive with nuts, grains, pulses and produce grown close to the soil; bone and shell come with meat and seafood. This is why supplier controls, ingredient specifications and incoming inspection are as important as any detector on the finished line.

What should we do if a physical hazard reaches the market?

Act on your recall and traceability procedure immediately. Identify the affected lots, determine the scope, notify the CFIA or FDA as required, and remove the product from sale. Then investigate the root cause: where the foreign material entered, why the control did not catch it, and what corrective and preventive action will stop it recurring. A fast, documented response limits both the safety risk and the regulatory exposure.

How MFLRC can help

MFLRC helps food manufacturers, importers and co-packers build preventive control plans and HACCP systems that control physical hazards by design, not by habit.

Our food safety support includes preventive control plan and HACCP development with a full hazard analysis covering biological, chemical and physical hazards; foreign-material control programme design, from supplier controls to metal detection and X-ray validation; gap assessments and mock inspections that test your plan the way CFIA or FDA will; supplier qualification and incoming-material controls; and recall and traceability readiness. When an inspection finding or a recall exposes a physical-hazard gap, we help build the corrective and preventive action to close it.

Worried a physical hazard could reach your customers? Contact MFLRC for a preventive control plan and foreign-material gap assessment tailored to your products.

Book a Food Safety Gap Assessment

Conclusion

The So Delicious recall is a small story with a large lesson. A handful of stones in a raw ingredient turned a finished, ready-to-eat product into a national recall, not because of a pathogen, but because a physical hazard was not caught before it left the plant. The Safe Food for Canadians Regulations, HACCP and FDA preventive controls all require physical hazards to be identified and controlled with the same discipline as biological ones. The producers who build layered, documented, verified foreign-material controls, from the supplier to the final detector, are the ones who keep stones out of the dessert and their brand off the recall list.