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Recap of the Elo Qualité webinar: Food Safety – Fast, Optimized Environmental Monitoring
Read more »Salmonella spp.: the pathogen that strikes everywhere, from eggs to dry goods
Salmonella is the leading cause of foodborne outbreaks in Europe. Long associated with eggs and poultry, it is now also identified as a persistent threat in dry products, an area many manufacturers still underestimate. Here’s the essential rundown, and how to detect it before it reaches your finished product.
Download the complete Salmonella fact sheet
A technical, summary resource designed for quality and HACCP managers:
- Detailed food and feed regulations
- The latest key European figures
- The specific risk in dry products
- Overview of detection methods
What is Salmonella?
79,703 confirmed cases in the European Union in 2024.
Salmonella remains the leading cause of foodborne outbreaks reported in Europe.
Source: EFSA/ECDC, The European Union One Health 2024 Zoonoses Report
The genus Salmonella actually includes only two species, Salmonella enterica and Salmonella bongori, but Salmonella enterica alone is divided into more than 2,600 serotypes, of which Enteritidis (58.4% of European cases) and Typhimurium (11%) are the most frequently associated with human infections. It is a motile, non-spore-forming bacterium that grows between roughly 5°C and 45°C, with an optimum around 35 to 40°C: it doesn’t multiply in a properly set refrigerator, but survives there without difficulty. It tolerates a fairly wide pH range (4.5 to 9, optimum around 6.5 to 7.5) and stops multiplying below a water activity of about 0.93 to 0.94, a threshold that dry products naturally fall below without this guaranteeing its destruction. A key point for manufacturers: its heat resistance increases as water activity decreases, which explains why it is so hard to eliminate by cooking in matrices such as chocolate or peanut butter.
Why is it a specific risk for food, feed, and pet food manufacturers?
Salmonella remains, above all, the leading cause of foodborne outbreaks reported in Europe, very largely linked to conventional animal supply chains. Its natural reservoir is the digestive tract of animals, particularly poultry, but also pigs, cattle, and certain reptiles, which explains its recurring presence in eggs, meat, and their derivatives. Cross-contamination remains a major transmission route, whether in the kitchen, a cutting workshop, or a manufacturing unit, as soon as a contaminated product comes into contact with a safe product, equipment, or a surface. It’s this combination of a natural presence widespread in livestock farming and a remarkable survival capacity, in both wet and dry conditions, that makes Salmonella a cross-cutting risk hard to confine to a single sector.
Why is Salmonella a specific risk in dry products?
Contrary to popular belief, Salmonella is not only a risk in fresh or refrigerated products. EFSA identifies it as one of the three most concerning bacterial hazards for persistence in production environments for low-water-activity products: chocolate, powders, cereals, sesame, peanut butter, almonds. Worse, the bacterium can enter a “viable but non-culturable” state there, making it harder to detect with conventional methods.
Regulatory framework
The European regulatory framework operates on two distinct, complementary levels. Upstream, Regulation (EC) 2160/2003 requires monitoring and control plans on farms, particularly poultry farms, with numerical prevalence-reduction targets for serotypes considered a public health priority.
Downstream, Regulation (EC) 2073/2005 sets a strict food safety criterion: total absence of Salmonella in a wide range of ready-to-eat foods, with a positive result systematically leading to withdrawal or recall from the market.
For the animal nutrition sector, Regulation (EC) 183/2005 governs animal feed hygiene using an approach based on HACCP principles, with a specific French approval known as the “salmonella approval” for manufacturers of compound feed intended for breeding flocks of more than 250 animals.
Outside the European Union, the Codex Alimentarius serves as the international reference for structuring comparable requirements.
Which products and production areas are most exposed?
Eggs and egg products
Poultry and pork meat
Vegetables, fruit and vegetable juices
Dry, low-moisture products (chocolate, powders, cereals)
In food processing, the most sensitive areas are those where raw materials and finished products can cross paths:
- Meat or poultry receiving and cutting stations,
- Egg shelling and packaging areas,
- Poorly controlled water and cleaning circuits.
In animal nutrition, the risk is concentrated on:
- Storage silos,
- Conveyors and mixing areas where dust and residue from contaminated raw materials can build up over time.
In both cases, equipment shared between several batches with no intermediate cleaning, as well as the presence of pests such as rodents or birds, remain well-documented aggravating factors.
How can you detect Salmonella quickly, before it contaminates the finished product?
Faced with a pathogen that settles durably into the production environment, regular environmental monitoring (surfaces, equipment, risk areas) is now recognized as the most effective detection lever, well ahead of finished-product control alone.
The LoopDeetect range lets you quickly screen surfaces and the production environment, with:
From sampling to result in under 90 minutes
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A method that's simple to integrate and use on-site
A method with no enrichment, no handling, and no lab equipment. With ready-to-use devices and reagents.
No compromise on performance
Our solutions are validated to ISO 16140-2, and deliver performance equivalent to reference methods.
LoopDeetect Salmonella spp certified AOAC PTM XXXXXX.
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Recap of the Elo Qualité webinar: Food Safety – Fast, Optimized Environmental Monitoring
Read more »Frequently asked questions about Salmonella
What are the Salmonella control obligations?
In Europe, two texts structure Salmonella control. Regulation (EC) 2160/2003 requires control and monitoring plans on farms, particularly poultry farms, with prevalence-reduction targets by serotype. Regulation (EC) 2073/2005, for its part, sets a food safety criterion of total absence of Salmonella in a wide range of ready-to-eat foods. These two obligations work together: one acts upstream, on the live animal and its environment, the other downstream, on the finished product.
Source: Regulation (EC) 2160/2003; Regulation (EC) 2073/2005.
What does EC Regulation 183/2005 provide for Salmonella in animal feed?
Regulation (EC) 183/2005 governs animal feed hygiene and relies on an approach based on HACCP principles, with prerequisite programs designed to prevent cross-contamination between raw materials, additives, and compound feed. In France, this framework gave rise to a specific approval known as the “salmonella approval” which can be granted to manufacturers of compound feed intended for breeding flocks of more than 250 animals of the Gallus gallus and turkey species. This approval requires enhanced controls to limit the introduction of Salmonella into the animal feed chain. This is an important point of vigilance for manufacturers supplying the breeding poultry sector.
Source: Regulation (EC) 183/2005; Order of April 23, 2007; ANSES Opinion, Salmonella spp. in animal feed.
What are the main routes of cross-contamination between raw materials and compound feed?
Plant-based raw materials, such as oilseed meal or cereals, can introduce Salmonella if they have been in contact with contaminated soil, water, or animal droppings. Equipment shared between different batches, dust suspended in silos and conveyors, and the presence of rodents or birds in storage areas are other frequent vectors of cross-contamination. Once introduced, the bacterium can persist for a long time in dust and organic matter residue that accumulates in manufacturing circuits. This is why preventing cross-contamination is central to the HACCP plans required by Regulation 183/2005.
Source: Regulation (EC) 183/2005; ANSES Opinion, Salmonella spp. in animal feed.
Which products and matrices are most exposed to Salmonella?
Eggs and egg products remain the matrix most frequently associated with Salmonella-related foodborne outbreaks in Europe, followed by poultry and pork meat. Vegetables and fruit and vegetable juices can also be contaminated, notably via irrigation water. The latest European zoonoses report confirms that the Salmonella-egg pairing generates the highest number of outbreaks and hospitalizations among all foodborne pathogens under surveillance. This data illustrates why the egg sector remains a priority target for monitoring plans.
Source: EFSA/ECDC, The European Union One Health 2024 Zoonoses Report.
Can Salmonella survive in low-water-activity dry products?
Yes, and it’s a steadily growing phenomenon. EFSA identifies Salmonella enterica in low-water-activity products, such as chocolate, cereals, powders, sesame, peanut butter, or almonds, as one of the three most concerning bacterial hazards for persistence in food production environments. The bacterium survives particularly well in dry, fat-rich matrices, where it can persist for long periods despite the lack of water available for its multiplication. This is an essential point of vigilance for dry-product manufacturers, who are often less accustomed to this risk than fresh or refrigerated product sectors.
Source: EFSA Journal 2024;22(1):8521, Koutsoumanis et al., “Persistence of microbiological hazards in food and feed production and processing environments”.
Are there documented examples of Salmonella contamination in dry products?
Yes, one particularly well-documented example dates back to 2022. EFSA and ECDC investigated a multinational outbreak of monophasic Salmonella Typhimurium linked to chocolate products, mainly affecting children under 10 in 12 European countries. The hospitalization rate observed during this episode reached 41.3%, a high level that illustrates the potential severity of contamination in this type of matrix. This episode strongly contributed to raising awareness in the food industry of the specific risks of dry, low-moisture products.
Source: ECDC/EFSA Rapid Outbreak Assessment, April 2022, DOI 10.2903/sp.efsa.2022.EN-7318.
What is the viable-but-non-culturable (VBNC) state, and why does it complicate Salmonella detection?
Under the effect of desiccation, Salmonella can enter a state known as “viable but non-culturable,” or VBNC. In this state, the cells remain alive but lose their ability to form colonies on the conventional culture media used in laboratories. The direct consequence is a risk of a false negative result: the product is declared compliant when the bacterium is actually present. Some studies also show that cells revived from this VBNC state can retain their pathogenic capacity, making this a safety issue and not just an analytical one.
Source: Finn et al., 2013, Frontiers in Microbiology, DOI 10.3389/fmicb.2013.00331; Zhang et al., 2023, MDPI, review on VBNC bacteria.
Why is the choice of detection method particularly critical for dry products?
Conventional detection methods, whether traditional or so-called rapid, generally rely on a pre-enrichment step designed to proliferate bacterial cells before analysis. However, in dry products, Salmonella cells are often damaged or in a VBNC state, which makes them unable to multiply properly during this step, with a risk of false negatives as a result. Certain compounds naturally present in dry products, such as herbs, spices, or dehydrated onion, can also inhibit bacterial growth during enrichment, adding a further difficulty. This is why detection methods that don’t require pre-enrichment, particularly those based on direct RNA detection, are presented as an interesting alternative for this type of matrix.
Source: Fakruddin et al., 2013, Rapid Microbiology; Li et al., 2020, Frontiers in Microbiology, DOI 10.3389/fmicb.2020.01859.
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