Bacillus cereus: an important foodborne pathogen

Ο Bacillus cereus είναι ένα σπορογόνο βακτήριο ευρύτατα διαδεδομένο στο περιβάλλον. Τα περισσότεραστελέχη του αναπτύσσονται σε θερμοκρασίες μεταξύ 10° και 42° C, κυρίως σε αερόβιες συνθήκες, αλλά μπορεί να αναπτυχθούνκαι σε αναερόβιες συνθήκες. Η τιμή D1 2 1 για τους σπόρους του Β. cereus είναι συνήθως μεταξύ 0.03 min και 2.35 min. Τοβακτήριο παράγει τουλάχιστον πέντε διαφορετικές εντεροτοξίνες (HBL, Nhe, CytK, BceT και FM) και μια εμετική τοξίνη. Οιεντεροτοξίνες HBL, Nhe και CytK είναι οι αιτιολογικοί παράγοντες στην πρόκληση της διαρροϊκής νόσου. Οι εντεροτοξίνες είναι ευαίσθητες στη θερμική επεξεργασία και αδρανοποιούνται με θέρμανση στους 56° C για 5 min. Επίσης, είναι ευαίσθητεςσε χαμηλές τιμές pH, στη δράση των πρωτεολυτικών ενζύμων και αδρανοποιούνται στο όξινο περιβάλλον του στομάχου. Έχειδιαπιστωθεί σε in vitro μελέτες ότι η εμετική τοξίνη του Β. cereus παραμένει σταθερή ακόμη και μετά από θέρμανση στους 121°C για 2 h, ενώ είναι ιδιαίτερα ανθεκτική σε χαμηλές τιμές pH (μέχρι 2) και στην πρωτεόλυση. Συνεπώς, μπορεί να παραμείνειδραστική στο όξινο περιβάλλον του στομάχου και στην επίδραση της πρωτεολυτικής δράσης των ενζύμων του εντερικούσωλήνα. Ο Β. cereus προκαλεί μια διαρροϊκή και μια εμετική μορφή τροφιμογενούς νόσου. Η πρώτη μορφή προκαλείται απότις εντεροτοξίνες του Β. cereus που παράγονται στον εντερικό σωλήνα μετά τη βλάστηση των σπόρων και την ανάπτυξη τωνβλαστικών μορφών του βακτηρίου, με κύρια συμπτώματα τα υδαρή κόπρανα και το κοιλιακό άλγος. Η δεύτερη μορφήπροκαλείται από την πρόσληψη της προσχηματισμενης στα τρόφιμα τοξίνης. Τα συμπτώματα είναι ναυτία και εμετός πουπεριστασιακά συνοδεύονται από κοιλιακό άλγος ή διάρροια. Οι τροφιμογενείς λοιμώξεις που προκλήθηκαν από τον Β. cereusέχουν συσχετιστεί με διάφορα είδη τροφίμων. Η εμετική μορφή συχνότερα έχει συσχετιστεί με την κατανάλωση ρυζιού,ζυμαρικών και άλλων αμυλούχων τροφίμων, ενώ η διαρροϊκή με την κατανάλωση γαλακτοκομικών προϊόντων, λαχανικών καικρέατος. Τα τρόφιμα που συχνότερα εμπλέκονται στην πρόκληση νόσου από το Β. cereus είναι το γάλα και τα γαλακτοκομικάπροϊόντα. Μεταξύ των τροφιμογενών λοιμώξεων που έχουν αναφερθεί στη Βόρεια Αμερική, στην Ευρώπη και την Ιαπωνία,οι περιπτώσεις που αποδόθηκαν οτονΒ. cereus αποτελούσαν το 1% έως 22%. Όμως, τα περισσότερα κρούσματα τροφιμογενούςνόσου από τον Β. cereus έχουν συσχετιστεί με την κατανάλωση μαγειρεμένων τροφίμων που ψύχθηκαν αργά και διατηρήθηκανσε ακατάλληλες συνθήκες ψύξης. Οι τροφιμογενείς νόσοι από τον Β. cereus αποτελούν σημαντικό πρόβλημα σε εστιατόριακαι επιχειρήσεις τροφοδοσίας. Η εφαρμογή μέτρων, όπως η τήρηση των αρχών της Ορθής Βιομηχανικής Πρακτικής (GoodManufacturing Practice, GMP) και του Συστήματος Ανάλυσης των Κρίσιμων Σημείων Ελέγχου (Hazard Analysis CriticalControl Points System, HACCP), στην παρασκευή των τροφίμων μπορούν να αποτρέψουν τη μόλυνση των τροφίμων μεπαθογόνα βακτήρια, όπως είναι ο Β. cereus.Β. cereus is a spore-forming bacterium, frequently found in the environment. Most of the strains can grow at a temperature range of 10° - 42° C. B. cereus grows under aerobic conditions, but anaerobic growth is, also, feasible. D1 2 1 values of the spores of B. cereus strains are usually in the range of 0.03 to 2.35 min. The pathogen produces at least five different enterotoxins (HBL, Nhe, CytK, BceT and FM) and one emetic toxin. The enterotoxins HBL, Nhe and CytK are the etiological agents of the B. cereus diarrhoeal disease. The enterotoxins are heat sensitive and can be inactivated by heating at 56° C for 5 min. They are, also, sensitive to low pH and proteolytic activity of enzymes and, subsequently, are inactivated in the acid environment of the stomach.B. cereus emetic toxin has been kept stable even in a heat treatment at 121° C for 2 h in in vitro tests. The emetic toxin is highly resistant to low pH (as low as 2) and to proteolysis. Thus, the emetic toxin cannot be inactivated in the acidic environment of the stomach and the enzyme proteolytic activity in the intestinal tract. B. cereus causes either a diarrhoeal or an emetic type of foodborne disease. The diarrhoeal disease is caused by the B. cereus enterotoxins, which are formed in the intestinal tract after the spores' germination and the subsequent growth of the vegetative cells. The symptoms are watery diarrhoea, abdominal cramps and pain. The emetic disease is caused by the ingestion of the preformed toxins in the foods. The symptoms are nausea and vomiting, occasionally followed by abdominal pain or diarrhoea. Foodborne outbreaks caused by B. cereus have been associated with various foods. The emetic disease has often been associated with the consumption of rice, pasta and other starchy foods, while the diarrheal disease is often linked to the consumption of dairy products, vegetables and meat. The most common food sources for B. cereus infections in humans are milk and dairy products. Among the reported foodborne outbreak cases in North America, Europe and Japan attributed to B. cereus represent a percentage of 1% to 22%. Most B. cereus foodborne cases were associated with the consumption of cooked foods that were cooled slowly and stored under improper refrigeration conditions. Foodborne diseases caused byB. cereus constitute a major problem in restaurants and catering services. Application of control measures, such as Good Manufacturing Practices (GMP) and Hazard Analysis Critical Control Points system (HACCP), in food processing lines can prevent contamination of the foods with pathogens like B. cereus

Bacillus cereus: an important foodborne pathogen

B. cereus is a spore-forming bacterium, frequently found in the environment. Most of the strains can grow at a temperature range of 10 degrees - 42 degrees C. B. cereus grows under aerobic conditions, but anaerobic growth is, also, feasible. D(121) values of the spores of B. cereus strains are usually in the range of 0.03 to 2.35 min. The pathogen produces at least five different enterotoxins (HBL, Nhe, CytK, BceT and FM) and one emetic toxin. The enterotoxins HBL, Nhe and CytK are the etiological agents of the B. cereus diarrhoeal disease. The enterotoxins are heat sensitive and can be inactivated by heating at 56 degrees C for 5 min. They are, also, sensitive to low pH and proteolytic activity of enzymes and, subsequently, are inactivated in the acid environment of the stomach. B. cereus emetic toxin has been kept stable even in a heat treatment at 121 degrees C for 2 h in in vitro tests. The emetic toxin is highly resistant to low pH (as low as 2) and to proteolysis. Thus, the emetic toxin cannot be inactivated in the acidic environment of the stomach and the enzyme proteolytic activity in the intestinal tract. B. cereus causes either a diarrhoeal or an emetic type of foodborne disease. The diarrhoeal disease is caused by the B. cereus enterotoxins, which are formed in the intestinal tract after the spores' germination and the subsequent growth of the vegetative cells. The symptoms are watery diarrhoea, abdominal cramps and pain. The emetic disease is caused by the ingestion of the preformed toxins in the foods. The symptoms are nausea and vomiting, occasionally followed by abdominal pain or diarrhoea. Foodborne outbreaks caused by B. cereus have been associated with various foods. The emetic disease has often been associated with the consumption of rice, pasta and other starchy foods, while the diarrheal disease is often linked to the consumption of dairy products, vegetables and meat. The most common food sources for B. cereus infections in humans are milk and dairy products. Among the reported foodborne outbreak cases in North America, Europe and Japan attributed to B. cereus represent a percentage of 1% to 22%. Most B. cereus foodborne cases were associated with the consumption of cooked foods that were cooled slowly and stored under improper refrigeration conditions. Foodborne diseases caused by B. cereus constitute a major problem in restaurants and catering services. Application of control measures, such as Good Manufacturing Practices (GMP) and Hazard Analysis Critical Control Points system (HACCP), in food processing lines can prevent contamination of the foods with pathogens like B. cereus

Foodborne viruses and innovative non-Thermal food-Processing technologies

In recent years, several foodborne viruses’ outbreaks have been recorded worldwide. Most of the foodborne viruses have a low infection dose, are stable and can persist and survive in foods for a long time without loss of infectivity. The most important foodborne viruses are: human norovirus (HuNoV), human rotavirus (HRV), hepatitis A virus (HAV), hepatitis E virus (HEV), human astrovirus (HAstV), Aichi virus (AiV), sapovirus (SaV), human adenovirus (HAdV) and enterovirus (EV). In recent years, innovative non-thermal food-processing technologies including high-pressure processing (HPP), cold plasma (CP), ultraviolet light (UV), irradiation and pulsed electric field (PEF) for improving the quality and safety of foods, including foods of animal origin, have been under research. This review presents the recent data on foodborne viruses and reviews the innovative non-thermal technologies for the control of the foodborne viruses in foods. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Inactivation of foodborne viruses by the cold plasma technology

Cold plasma (CP) is an innovative non-thermal food processing method. CP refers to a partially or completely ionized gas containing reactive chemical species, which are active against microorganisms, including viruses or enzymes of foods. CP has a minimal effect on the quality attributes of foods and can also elongate the shelf life of foods. Foodborne outbreaks caused by viruses have been increased in various countries in recent years. The research works on the inactivation effect of CP against viruses including foodborne viruses have been also increased in recent years. The most important foodborne viruses are human norovirus (HuNoV) and hepatitis A virus (HAV), involved in several outbreaks worldwide. Human astrovirus (HAstV), human adenovirus (HuAdV), Aichi virus (AiV), sapovirus (SaV) and enterovirus (EV) are also notable foodborne viruses and were associated in sporadic cases. The CP treatment proved efficient for the inactivation of foodborne viruses such as HuNoV and HAV. The present work reviews the CP as a non-thermal food processing technology and present the published data on the effect of CP process on foodborne viruses in foods. © 202

Inactivation of foodborne viruses by high-pressure processing (Hpp)

High-pressure processing (HPP) is an innovative non-thermal food preservation method. HPP can inactivate microorganisms, including viruses, with minimal influence on the physicochemi-cal and sensory properties of foods. The most significant foodborne viruses are human norovirus (HuNoV), hepatitis A virus (HAV), human rotavirus (HRV), hepatitis E virus (HEV), human astrovirus (HAstV), human adenovirus (HuAdV), Aichi virus (AiV), sapovirus (SaV), and enterovirus (EV), which have also been implicated in foodborne outbreaks in various countries. The HPP inactivation of foodborne viruses in foods depends on high-pressure processing parameters (pressure, temperature, and duration time) or non-processing parameters such as virus type, food matrix, water activity (aw), and the pH of foods. HPP was found to be effective for the inactivation of foodborne viruses such as HuNoV, HAV, HAstV, and HuAdV in foods. HPP treatments have been found to be effective at eliminating foodborne viruses in high-risk foods such as shellfish and vegetables. The present work reviews the published data on the effect of HPP processing on foodborne viruses in laboratory media and foods. © 2021 by the authors. Licensee MDPI, Basel, Switzerland