# Innovative Sensor Approach to Follow _Campylobacter jejuni_ Development
## 1 Introduction  
Nowadays we live in the safest environment regarding the food industry. Organizations as EFSA (European Food Safety Agency), WHO (World Health Organization), and FAO (Food and Agriculture Organization) determine, organize and rule all the regulations that control every single aspect of food safety, security and trading. Even if the risk perception regarding the food industry is not one of the first concerns of the population in non-developing countries [1, 2], food poisoning is still the first cause of hospitalization in the world. The CDC (Center of Disease Control) estimates that each year 48 million people get sick from a foodborne illness, 128,000 are hospitalized and 3000 die just in the USA [3]. The FoodNet (Foodborne Diseases Active Surveillance Network) division of the CDC affirms in its 2017 report that the incidence of infections per 100,000 people was highest for _Campylobacter spp_ and _Salmonella spp_ from 2016 to 2017, which is similar to previous years. The situation in Europe for _Campylobacter spp_ infections is illustrated by the Campylobacteriosis-Annual epidemiological report published the 30 January of 2017 by the ECDC (European Center of Disease Control) from data collected in 2014 [4]. The report affirms that 240,379 confirmed cases were reported in 2014 with a rate of campylobacteriosis of 59.8 cases per 100,000 population in the EU/EEA, representing a 13% increase compared with the previous year. Human campylobacteriosis was more common inchildren below five years of age and in general was slightly higher for males than females across all age groups. Campylobacteriosis shows a clear seasonality, with a sharp peak of cases in July, trend that it is confirmed by the CDC as well. At the beginning of the summer of 2018 in Pescara (Italy), 180 cases of intoxicated children were reported and identified as Campylobacteriosis infection. The most representative etiologic agent for campylobacteriosis is _Campylobacter jejuni_. It is a slender, spirally curved rod that possesses a single polar flagellum at one or both ends of the cell. It is oxidase and catalase positive, is microaerophilic, requiring small amounts of oxygen (3-6%) for growth; its optimum growth temperatures on solid media are 37 \({}^{\circ}\)C, and it grows well at pH 5.5-8.0. _C. jejuni_ is associated with warm-blooded animals, in fact a large percentage of all major livestock animals have been shown to contain these organisms in their feces [5; 6]. Some strains of _C. jejuni_ produce a thermolabile enterotoxin (CJT), that has been reported to have some similar properties with the enterotoxins of _Vibrio cholerae_ (CT) and _Escherichia coli_ (LT) [7; 8]. Many livestock warm-blooded animals can carry in their intestines, liver and giblets cells of _C. jejuni_ that can be transferred to other edible parts of an animal when it's slaughtered. In the USA in 2014, National Antimicrobial Resistance Monitoring System (NARMS) testing found _C. jejuni_ on 33% of raw chicken bought from retailers [9]. _Campylobacter spp_ infection can also be transmitted through unpasteurized milk ingestion when a cow has _C. jejuni_ cells in its udder or when milk is contaminated with manure [10]. Moreover, most problematic foods regarding _Campylobacter spp_ infection are those consumed raw, such as fruits and vegetables that can be contaminated through contact with soil containing feces from cows, birds or other animals [11]. Animal feces can also contaminate water sources, such as lakes and streams. Today there are many techniques that can be used in the identification of this type of contamination, many of which have limits related to the collection time of responses, high complexity or the possibility of being reused several times. In the last few years, different kinds of sensors have been developed for _C. jejuni_ detection. They are essentially DNA-biosensors, of which specificity is due to oligonucleotide probes covalently immobilized on the sensing surface.