Salmonella enteritidis (Salmonella enterica sub-specie)
Salmonella is a pathogen and can cause gastrointestinal infections referred to as salmonellosis. Information about other pathogens can be found here. The pathogen occurs naturally in the gastrointestinal tracts of animals such as pigs, poultry, birds, rodents, reptiles, and insects. They are spread in the environment through the faeces of these animals. People can contract salmonellosis when they consume foods contaminated with Salmonella bacteria. People who contract salmonellosis remain carriers/excretory of Salmonella bacteria for a long time (6–8 weeks).
|D value||D60 = 1-10 min|
|Oxygen demand (O2)||fa|
|Incubation time||8 – 72 hours|
|Expensive||1 – 3 days|
|Dose-Response relationship DR||> 100 000 (sometimes 10)|
|Food poisoning (FP) / Food infection (FI)||FI|
|Symptoms||Diarrhoea, nausea, vomiting, headache, fever, stomach pain|
|Products||Poultry, eggs, raw meat, milk, vegetables|
|Other information sheets||Bad Bug book FDA|
|Knowledge sheets Dutch Food Safety Authority|
|Related Regulations||2160-2003 Control Salmonella-zoonotic agent|
|Case Study Status of food safety||Salmonella in Polish eggs|
|Salmonella in vegetable products|
|RIVM Reports||Salmonella workshop 2018|
|Salmonella chicken feed|
Salmonella bacteria belong to the species Salmonella enterica (S. enterica). This species belongs to the Enterobacteriaceae family. They can grow with or without oxygen. They are Gram-negative and have flagella (whip threads) with which they can move in a fluid. Usually, S. enterica bacteria are further designated based on the immunological composition of the cell wall and the flagella present on it. In total, slightly more than 2000 immunological types, also called serotypes, are known. Each serotype has its name, usually a place name where the organism was first isolated. The serotypes are written as follows: Salmonella Agona (S. Agona). Agona is a place in Ghana.
Growth of Salmonella
Salmonella bacterial growth takes place within several limits. These limits are listed in Table 1.
Table 1. Limits within which S. enterica can grow.
|Parameter||Reported Values |
|Minimum temperature||5.2 ºC|
|Maximum temperature||45-46 ° C|
|Water activity (aw)|
|Optimum pH||6.5 – 7.5|
Table 2 provides data on the survival and resistance of S. enterica. The organisms survive for a long time in frozen products and survive for quite a long time in dry products such as chocolate and milk powder. The heat resistance is usually expressed in the time (minutes or seconds) it takes to achieve a 10-fold reduction at a specific temperature. For example, a D60.0 value of 7.5 min means that the product containing the micro-organisms must be heated for 7.5 minutes at 60.0 o C to reduce the number of S. enteric organisms present by a factor of 10. to reduce. To reduce the organisms present by 100, the pathogen must be at 60.0°C and heated for 2 x 7.5 = 15 minutes.
Table 2. Survival and resistance S. enterica
|Heat D57.2 (sucrose solution)||95 min|
|Heat D60.0 (NaCl solution)||7.5 min|
|Heat D60.0||(pea soup)|
|Heat D60.0||(egg product, pH 8.0)|
|Heat D60.0||(egg product, pH 5.5)|
It should be noted that there can be significant differences in heat sensitivity between the various serotypes. However, the composition and the pH of the product in which S. enterica is present also determine to a large extent the resistance to heating (see table 2). The most heat-resistant S. enterica is the serotype S. Senftenberg.
Illness and symptoms
The illness usually occurs between 10 to 48 hours after Salmonella ingestion and usually lasts 3-6 days. The main disease symptoms are:
- Nausea and vomiting;
- Abdominal pain and diarrhoea;
- Fever and headache;
- After 3-4 weeks, the joints can sometimes start to hurt.
People of all age groups can contract salmonellosis. In young children, the elderly (> 70 years) and people with weakened immunity, the disease manifest itself to a more serious degree and medical attention is often necessary.
Salmonella associated foods
- Raw meat and poultry meat;
- Eggs, raw milk and products made from raw milk;
- Fish, shrimp and frog legs;
- Salad dressings and (with cream) filled pastries;
- Cocoa and chocolate;
- Seed sprouts, vegetables and fruit.
General Prevention Salmonella
- Keep eggs and raw meat products (meat, fish, poultry meat) refrigerated;
- Do not use cracked or dirty eggs; – Avoid cross-contamination between raw and prepared products; – After contact with raw meat and egg contents, kitchen utensils and hands should be washed with a hot soap solution; – During baking and roasting, use a calibrated temperature gauge to measure the internal temperature of meat and poultry meat; – Only use pasteurized products (dairy, liquid egg products and fruit juices).
Incidence in the Netherlands. In the Netherlands, 35,000 – 50,000 people contract salmonellosis every year. This equates to approximately 206-290 cases per 100,000 persons per year. Salmonella-contaminated eggs, pork, and poultry products are the primary sources of infection. In the United States, the incidence is identical.