**8. Conclusion**

66 Salmonella – A Dangerous Foodborne Pathogen

**Butter** is produced by the mechanical churning of the cream obtained after centrifugation of cheese whey. It can be *sweet* if the cream is used as it is, or *ripened* if it comes from cream that was first matured with the addition of starter enzymes. In most cases, the raw material for butter is subjected to pasteurization in butter before being processed, but in some cases butter is obtained directly from the cream of raw, unpasteurized milk. It is clear that in this second case *Salmonella* may be present in the butter from the start of the making process because the raw material itself was contaminated. In the case of butter made from pasteurized cream, however, a possible contamination with *Salmonella* cannot be excluded, because the pathogen could infect the finished product through a secondary contamination. In the past decades, in fact, several episodes of human salmonellosis caused by butter contaminated with *Salmonella* occurred, but over the years these episodes have registered a sharp decline, due to the fact that producers dedicate more attention to production hygiene and to the fact that butter is now rarely made with unpasteurized cream. The EU has established with EC Regulation 2073/05 that "cheese, butter and cream made from raw milk or milk subjected to heat treatment at sub-pasteurization temperatures" should not contain even one living cell of *Salmonella* in 125 g (25 g in 5 units of the sample) of product throughout its shelf life. **Dried milk products** as a rule, these foods are products obtained after pasteurized milk is nebulized in towers where a very dry and hot air current circulates, but on the market you can find lyophilised products, i.e. put through the cold-removal of water, not involving the use of high temperatures. The sanitary characteristics of milk powders, therefore, is determined by: (i) the microbiological quality of the raw material, (ii) the conditions of the production process (with or without heat treatment), (iii) the possibility of the dehydrated/lyophilised product to be contaminated with salmonellae after its processing. Salmonellae are sensitive to normal temperatures applied in the production process of dried milk products, so it is logical to expect that such products are rarely at risk of containing *Salmonella*, unless they are contaminated after this process, during packaging or storage. In these cases, dried milk products may be a risk to human health, since salmonellae can survive for months in substrates with low water content, such as bone meal and powdered foods. The possible dangers of these products is also enhanced by the fact that such foods are usually meant for very young children, much more sensitive than adults to even minor loads of *Salmonella*. For this reason, the EU has established by law (EC Regulation 2073/05) that "powdered milk and powdered whey" should not contain even one living cell of *Salmonella* in 125 g of product throughout its shelf life. **Ice cream** is a complex food made of various ingredients, including eggs and milk, where water crystallizes, forming a homogeneous creamy mass, thanks to the high amount of fat. As such, also ice cream can be contaminated with *Salmonella*, if it is contained in the raw milk or appears in the manufacturing process. Over the past decades, in fact, many outbreaks of salmonellosis caused by the consumption of ice cream have been documented, but it was not always possible to establish with certainty whether the pollution came from the raw milk or from the eggs, which are also used raw. For several years now, the use of pasteurized milk and eggs has become a habit for producing ice cream, so the risk of *Salmonella* contamination in these products has been greatly reduced. But we must remember that ice cream, due to its almost always neutral or slightly acidic pH levels and to its high amount of free water (Aw), can be an excellent substrate for the survival and growth of *Salmonella*, if the latter managed to infect it. The risks to public health may be greater for

All this makes it difficult to control and prevent these toxi-infections; as a result, it is necessary for epidemiologists, clinicians and microbiologists as well as veterinarians to collaborate in order to launch an integrated approach to solve the problem. In order to prevent the occurrence of salmonellosis, it is therefore essential to know which animals and/or which foods most frequently carry the pathogens which have led to sporadic cases or episodes of disease in humans. Epidemiological data should then be given special attention and consideration by meat producers and in general by anyone whose role it is to carry out investigations on food, as they can provide useful information regarding changes or additions to be made to the eradication plans against *Salmonella*.
