Prevalence and evaluation strategies for viral contamination in food products: Risk to human health-a review

Current perspectives of viral hepatitis

Viral hepatitis represents a major danger to public health, and is a globally leading cause of death. The five liver-specific viruses: Hepatitis A virus, hepatitis B virus, hepatitis C virus, hepatitis D virus, and hepatitis E virus, each have their own unique epidemiology, structural biology, transmission, endemic patterns, risk of liver complications, and response to antiviral therapies. There remain few options for treatment, in spite of the increasing prevalence of viral-hepatitis-caused liver disease. Furthermore, chronic viral hepatitis is a leading worldwide cause of both liver-related morbidity and mortality, even though effective treatments are available that could reduce or prevent most patients' complications. In 2016, the World Health Organization released its plan to eliminate viral hepatitis as a public health threat by the year 2030, along with a discussion of current gaps and prospects for both regional and global eradication of viral hepatitis. Today, treatment is sufficiently able to prevent the disease from reaching advanced phases. However, future therapies must be extremely safe, and should ideally limit the period of treatment necessary. A better understanding of pathogenesis will prove beneficial in the development of potential treatment strategies targeting infections by viral hepatitis. This review aims to summarize the current state of knowledge on each type of viral hepatitis, together with major innovations.

Foodborne Viruses and Somatic Coliphages Occurrence in Fresh Produce at Retail from Northern Mexico

Foodborne disease outbreaks linked to consumption of vegetables have been often attributed to human enteric viruses, such as Norovirus (NoV), Hepatitis A virus (HAV), and Rotavirus (RoV). Information about the occurrence of these viruses is scarce in many fresh-producing countries. Viral contamination detection of indicators, such as somatic coliphages, could indirectly reflect the presence of viral pathogens, being a valuable tool for better viral risk assessment in food industry. This study aimed to establish the occurrence and correlation of foodborne viruses and somatic coliphages in leafy greens in northern Mexico. A total of 320 vegetable samples were collected, resulting in 80 composite rinses, 40 of lettuce and 40 of parsley. Somatic coliphages were determined using the EPA 1602 method, while foodborne viruses (HAV, RoV, NoV GI, and GII) were determined by qPCR. The occurrence of RoV was 22.5% (9/40, mean 2.11 log gc/g) in lettuce and 20% (8/40, mean 1.91 log gc/g) in parsley. NoV and HAV were not detected in any samples. Somatic coliphages were present in all lettuce and parsley samples, with mean levels of 1.85 log PFU/100 ml and 2.28 log PFU/100 ml, respectively. Spearman analysis established the correlation of somatic coliphages and genomic copies of RoV, resulting in an r2 value of - 0.026 in lettuce and 0.349 in parsley. Although NoV or HAV were undetected in the samples, the presence of RoV is a matter of concern as leafy greens are usually eaten raw, which poses a potential risk of infection.

Exploitation of the Antibacterial Properties of Photoactivated Curcumin as ‘Green’ Tool for Food Preservation

In the search for non-chemical and green methods to counteract the bacterial contamination of foods, the use of natural substances with antimicrobial properties and light irradiation at proper light waves has been extensively investigated. In particular, the combination of both techniques, called photodynamic inactivation (PDI), is based on the fact that some natural substances act as photosensitizers, i.e., produce bioactive effects under irradiation. Notably, curcumin is a potent natural antibacterial and effective photosensitizer that is able to induce photodynamic activation in the visible light range (specifically for blue light). Some practical applications have been investigated with particular reference to food preservation from bacterial contaminants.

In the landscape of SARS-CoV-2 and fresh fruits and vegetables: The fake and hidden transmission risks

From the first notification reporting to the WHO a cluster of coronavirus in Wuhan City (China), over 114 million cases of SARS‐CoV‐2 have been confirmed, with more than 2,530,000 deaths, and over 400,000 new cases and 10,000 deaths daily. Numerous viruses are susceptible to contaminate crops during growth, harvesting, handling, marketing and minimally processing, and these steps share one common factor which is human. Different studies showed that viruses might persist on different crops for periods of 2 to 14 days under different conditions such as refrigeration, household and freezing. Little is known on SARS‐CoV‐2, but preliminary studies showed that this virus might survive 24 hr on cardboard and 72 hr on plastic, materials used in fruits and vegetables packaging. Based on preliminary data, there is no evidence of food or food packaging being associated with transmission of SARS‐CoV‐2. Certainly, to date there is no scientific evidence that SARS‐CoV‐2 might be transmitted by a contact with, or the ingestion of contaminated fresh or minimally processed fruits and vegetables. However, this risk even though being considered improbable, it cannot be “completely and definitely” discarded or ignored, particularly where the virus is spreading in the word. Some agencies indicated that in case some commodities and handlers are contaminated among the multiple people involved from the farm to the table, a cross‐contamination may occur, and the risk of the contamination of food, food contact materials, and packaging from infected but asymptomatic workers should not be discarded even though considered “Very Low = meaning very rare but cannot be excluded.”

COVID-19 pandemic sheds light on the importance of food safety practices: risks, global recommendations, and perspectives

The outbreak of the coronavirus disease (COVID-19) is global health and humanitarian emergency. To respond effectively to this pandemic, it is mandatory to reaffirm science in its different fields of study, including the food safety area. Presently, we review food safety in times of COVID-19, exploring whether the virus can be transmitted by food or water; recommendations from regulatory agencies; perceptions of food hygiene practices during the pandemic; and post-pandemic perspectives. The review was based on papers published in Web of Science, Scopus, Pubmed, and covered recommendations of public health protection and regulatory agencies around the world. The transmission of the severe acute respiratory syndrome (SARS-CoV-2) by food was not confirmed until the present time. In any case, the protocols already established for food safety were reinforced, emphasizing the proper hygiene of hands after shopping, handling food packages, or before manipulating or eating food, adequate social distance, the use of individual protection equipment, the health of employees, and the proper preparation of food. It is hoped, in the post-pandemic scenario, to reach a better understanding of the particularities that led to greater care with food hygiene. Moreover, it is expected that the food system will creatively adapt the way meals are served.

The Significance of Mesophilic Aeromonas spp. in Minimally Processed Ready-to-Eat Seafood

Minimally processed and ready-to-eat (RTE) seafood products are gaining popularity because of their availability in retail stores and the consumers' perception of convenience. Products that are subjected to mild processing and products that do not require additional heating prior to consumption are eaten by an increasing proportion of the population, including people that are more susceptible to foodborne disease. Worldwide, seafood is an important source of foodborne outbreaks, but the exact burden is not known. The increased interest in seafood products for raw consumption introduces new food safety issues that must be addressed by all actors in the food chain. Bacteria belonging to genus Aeromonas are ubiquitous in marine environments, and Aeromonas spp. has held the title "emerging foodborne pathogen" for more than a decade. Given its high prevalence in seafood and in vegetables included in many RTE seafood meals, the significance of Aeromonas as a potential foodborne pathogen and a food spoilage organism increases. Some Aeromonas spp. can grow relatively uninhibited in food during refrigeration under a broad range of pH and NaCl concentrations, and in various packaging atmospheres. Strains of several Aeromonas species have shown spoilage potential by the production of spoilage associated metabolites in various seafood products, but the knowledge on spoilage in cold water fish species is scarce. The question about the significance of Aeromonas spp. in RTE seafood products is challenged by the limited knowledge on how to identify the truly virulent strains. The limited information on clinically relevant strains is partly due to few registered outbreaks, and to the disputed role as a true foodborne pathogen. However, it is likely that illness caused by Aeromonas might go on undetected due to unreported cases and a lack of adequate identification schemes. A rather confusing taxonomy and inadequate biochemical tests for species identification has led to a biased focus towards some Aeromonas species. Over the last ten years, several housekeeping genes has replaced the 16S rRNA gene as suitable genetic markers for phylogenetic analysis. The result is a more clear and robust taxonomy and updated knowledge on the currently circulating environmental strains. Nevertheless, more knowledge on which factors that contribute to virulence and how to control the potential pathogenic strains of Aeromonas in perishable RTE seafood products are needed.

Selected Viruses Detected on and in our Food

PURPOSE OF REVIEW

The purpose of this review is to provide an update on recent literature and findings concerning selected foodborne viruses. Two groups of viruses were selected: (a) the most important viruses contaminating food, based on numbers of publications in the last 5 years and (b) viruses infecting sources of food that might have an impact on human health.

RECENT FINDINGS

Important foodborne viruses such as norovirus, hepatitis A and rotavirus are usually "only" contaminating food and are detected on the surface of foodstuffs. However, they are threats to human public health and make up for the majority of cases. In contrast, the meaning of viruses born from within the food such as natural animal and plant viruses is still in many cases unknown. An exception is Hepatitis E virus that is endemic in pigs, transmitted via pork meat and is recognised as an emerging zoonosis in industrialised countries.

SUMMARY

Even though the clinical meaning of "new" foodborne viruses, often detected by next generation sequencing, still needs clarification, the method has great potential to enhance surveillance and detection particularly in view of an increasingly globalised food trade.