# Microbial Risk Assessment of Industrial Ice Cream Marketed in Italy
## 4 Discussion  
Although freezing appears to ensure the high microbiological safety of ice cream, it does not exclude the fact that the transmission of foodborne pathogens to humans can also occur through its consumption [12; 13; 28; 29; 30]. This is stressed by the results of the present study, which revealed the presence of \(L\). _monocytogenes_ in 16 store-bought industrial ice creams, and, in three of them, the loads were even beyond the legal limit (<100 cfu/g) allowed in Europe [31]. Major concerns are associated with vulnerable people such as YOPI, for whom even low loads of pathogens can result in serious outcomes [19]. In this regard, we underline that ice cream is widely consumed by children and also recommended in postoperative recovery diets in patients undergoing various types of surgeries [32; 33]. The microbiological quality and safety of industrial ice cream depend on many factors, which could be divided into three strictly interconnected groups: microbiological standards of the raw materials, the production process and the hygiene of the working environments [6]. Any ingredient used in the production of ice cream represents a source of microorganisms that can affect the composition of the microbial flora in the finished product [34]. In the first steps of production, the desired ingredients are blended to obtain a  
Figure 2: Correlation matrices between the results of different microbiological parameters obtained for 200 samples of industrial ice cream collected at different mass-market retailers. The value of the correlation coefficient (r) is reported inside each square. The results were arranged considering (a) all samples, (b) the samples with inclusions (toppings or decorations) and (c) samples without inclusions. liquid mix that will undergo a pasteurization treatment. If properly performed, pasteurization ensures the inactivation of pathogenic microorganisms and reduction of the vegetative microbial forms [35]. The use of raw materials with poor microbiological standards can negatively impact the effectiveness of the heat treatment, threatening the quality and safety of the product [6; 36; 37] Indeed, pasteurization treatments lose their effectiveness against spore-forms, thermodynamic microorganisms, thermostable myo- and bacterial toxins and heat-resistant enzymes possibly present in the raw materials, which may spoil the product and pose risks for the consumer's health [35]. The raw materials commonly used to produce industrial ice cream are milk, water, cream, butter, sugars, dairy or non-dairy fats and additives such as thickeners, stabilizers and emulsifiers. The industrial production of ice cream involves the use of liquid or powdered milk that has already undergone a heat treatment by the supplier [38]. The water used to mix the dry ingredients together is of drinkable quality and should not pose a risk if the distribution and storage facilities are properly managed. Even cream and butter, in their production processes, are subjected to heat treatments that ensure their microbiological safety [39]. Contamination by sugars, used in powder or syrup, should be limited only to certain types of osmophilic microorganisms considering that the high sugar content and the production process make them almost sterile [34]. Moreover, fats and additives are usually produced with techniques that involve high temperatures and therefore they should not represent an important source of contamination [40; 41]. In addition, the low moisture content of fats offers a further guarantee [42]. Many other ingredients, such as flavorings, colorings and inclusions, can be added to the mix after pasteurization, which, for the same reasons as the other ingredients, would not represent a real risk in themselves. However, although most of the ingredients should not be relevant sources of microorganisms or be able to support their growth, their contamination would threaten the safety of the ice cream already during production [43; 44].