The Effect of High-Pressure Processing on Infectivity ofCryptosporidium parvumOocysts Recovered from Experimentally Exposed Eastern Oysters (Crassostrea virginica)

Inactivating Food Microbes by High-Pressure Processing and Combined Nonthermal and Thermal Treatment: A Review

High-pressure processing (HPP) is a mild technology alternative to thermal pasteurization and sterilization of different food products. HPP has emerged to provide enormous benefits to consumers, i.e., mildly processed food and additive-free food. It effectively retains bioactive compounds and extends the shelf life of food commodities by inactivating bacteria, yeast, mold, and virus. The limitation of HPP in inactivating spores can be overcome by using other thermal and nonthermal processing sequentially or simultaneously with HPP. This review summarizes the applications of HPP in the fruits and vegetables, dairy, meat, fish, and poultry sector. It also emphasizes microbial food safety and the effectiveness of HPP in the load reduction of microorganisms. Comprehensive information about the synergistic effect of HPP with different techniques and their effectiveness in ensuring food safety is reported. The summarized data would be handy to interested researchers and industry personnel.

High-pressure processing of fish and shellfish products: Safety, quality, and research prospects

Seafood products have been one of the main drivers behind the popularity of high-pressure processing (HPP) in the food industry owing to a high demand for fresh ready-to-eat seafood products and food safety. This review provides an overview of the advanced knowledge available on the use of HPP for production of wholesome and highly nutritive clean label fish and shellfish products. Out of 653 explored items, 65 articles published during 2016-2021 were used. Analysis of the literature showed that most of the earlier work evaluated the HPP effect on physicochemical and sensorial properties, and limited information is available on nutritional aspects. HPP has several applications in the seafood industry. Application of HPP (400-600 MPa) eliminates common seafood pathogens, such as Vibrio and Listeria spp., and slows the growth of spoilage microorganisms. Use of cold water as a pressure medium induces minimal changes in sensory and nutritional properties and helps in the development of clean label seafood products. This technology (200-350 MPa) is also useful to shuck oysters, lobsters, crabs, mussels, clams, and scallops to increase recovery of the edible meat. High-pressure helps to preserve organoleptic and functional properties for an extended time during refrigerated storage. Overall, HPP helps seafood manufacturers to maintain a balance between safety, quality, processing efficiency, and regulatory compliance. Further research is required to understand the mechanisms of pressure-induced modifications and clean label strategies to minimize these modifications.

Raw meat based diet (RMBD) for household pets as potential door opener to parasitic load of domestic and urban environment. Revival of understated zoonotic hazards? A review

RMBD (acronym of Raw Meat Based Diet) and BARF diets (acronym for Biologically Appropriate Raw Food or Bones and Raw Food) account dietary regimens based on raw ingredients (including raw meat), popular in pet feeding. Animal tissues and organs as well as other uncooked ingredients are more and more popularly used by pet owners to feed household pets. However, the increased risk of exposure to microbiological and parasitic agents poses the question as to whether such diets may be recommendable to be handled and offered to domestic cats and dogs co-living in domestic and urban environment. Above all, the threat of human and animal infections by parasites from raw meat fed to pets is not sufficiently explored and tracked, meanwhile deserving particular surveillance, instead. At this regard, raw meat feeding to pets may represent a route of exposure to the increased risk of environmental load. In fact, some parasites typically found in rural environment can be given the chance to complete their life-cycle, for the closeness between definitive and intermediate hosts. This is of particular concern, as potentially infected pets serving as definitive hosts can become a continuous source of environmental diffusion of parasites, both at domestic and urban level. The handling of raw meat requires adequate knowledge and awareness of the hygienic principles to prevent the onset of disorders related to both manipulation by pet owners and uncooked food consumption by the pet. This review aimed to shed a comprehensive overview of the hygienic aspects related to raw pet feeding, as to handling of raw meat in domestic environment, with special emphasis on parasitic agents and related zoonotic hazards.

Aspects of high hydrostatic pressure food processing: Perspectives on technology and food safety

The last two decades saw a steady increase of high hydrostatic pressure (HHP) used for treatment of foods. Although the science of biomaterials exposed to high pressure started more than a century ago, there still seem to be a number of unanswered questions regarding safety of foods processed using HHP. This review gives an overview on historical development and fundamental aspects of HHP, as well as on potential risks associated with HHP food applications based on available literature. Beside the combination of pressure and temperature, as major factors impacting inactivation of vegetative bacterial cells, bacterial endospores, viruses, and parasites, factors, such as food matrix, water content, presence of dissolved substances, and pH value, also have significant influence on their inactivation by pressure. As a result, pressure treatment of foods should be considered for specific food groups and in accordance with their specific chemical and physical properties. The pressure necessary for inactivation of viruses is in many instances slightly lower than that for vegetative bacterial cells; however, data for food relevant human virus types are missing due to the lack of methods for determining their infectivity. Parasites can be inactivated by comparatively lower pressure than vegetative bacterial cells. The degrees to which chemical reactions progress under pressure treatments are different to those of conventional thermal processes, for example, HHP leads to lower amounts of acrylamide and furan. Additionally, the formation of new unknown or unexpected substances has not yet been observed. To date, no safety-relevant chemical changes have been described for foods treated by HHP. Based on existing sensitization to non-HHP-treated food, the allergenic potential of HHP-treated food is more likely to be equivalent to untreated food. Initial findings on changes in packaging materials under HHP have not yet been adequately supported by scientific data.

The use of High-Pressure Processing (HPP) to improve the safety and quality of raw coconut (Cocos nucifera L) water

This research investigated the use of high-pressure processing (HPP) for inactivating vegetative pathogens and spoilage microbiota in fresh unfiltered coconut water (Cocos nucifera L) from nuts obtained from Florida and frozen CW from Brazil with pH >5.0 and storage at 4 °C. Additionally, CW was evaluated to determine if it supported the growth and toxin production of Clostridium botulinum with or without the use of HPP when stored at refrigeration temperatures. Samples of fresh unfiltered CW were inoculated to 5.5 to 6.5 logs/mL with multiple strain cocktails of E. coli O157:H7, Salmonella spp. and Listeria monocytogenes and HPP at 593 MPa for 3 min at 4 °C. HPP and inoculated non-HPP controls were stored at 4 °C for 54 and 75 days for Florida CW and Brazil CW, respectively. Results of analyses showed HPP samples with <1 CFU/mL and no detection (negative/25 mL) with enrichment procedures for the 3 inoculated pathogens for all analyses. The non-HPP control samples did not show growth of the pathogens but a gradual decrease in levels to ca. 3-Logs/mL by day 54 in the fresh Florida CW and similarly in frozen Brazil CW by Day 75. Microbial spoilage of uninoculated samples was evaluated for normal spoilage microbiota through 120 days storage at 4 °C. Microbial counts remained at ca. 2-logs with no detectable signs of spoilage for HPP samples through 120 d. The non-HPP control samples spoiled within 2 weeks of storage at 4 °C with gas production, cloudiness, and off-odors. To evaluate if CW supports the growth and toxin production of C. botulinum, samples of unfiltered and filtered (0.2 μm) CW were inoculated with either proteolytic or non-proteolytic C. botulinum spores at 2 log CFU/mL that were processed at 593 MPa for 3 min and stored at 4 °C and 10 °C for 45 days. Inoculated positive and non-inoculated negative controls were prepared and stored as the HPP treated and non-HPP samples. No growth of C. botulinum or toxin production was detected in either the unfiltered or filtered CW regardless if products were HPP treated or not. All inoculated samples with C. botulinum spores were enriched at Day-45 in PYGS media to determine the viability of the inoculated spores at the end of shelf-life and screened for C. botulinum toxins. In all samples, C. botulinum toxin Types A, B and E were detected indicating spores were viable throughout the storage. Type F toxin was not detected possibly due to inherent conditions in the samples that may affected toxin screening.

Assessing viability and infectivity of foodborne and waterborne stages (cysts/oocysts) of Giardia duodenalis, Cryptosporidium spp., and Toxoplasma gondii: a review of methods

Giardia duodenalis, Cryptosporidium spp. and Toxoplasma gondii are protozoan parasites that have been highlighted as emerging foodborne pathogens by the Food and Agriculture Organization of the United Nations and the World Health Organization. According to the European Food Safety Authority, 4786 foodborne and waterborne outbreaks were reported in Europe in 2016, of which 0.4% were attributed to parasites including Cryptosporidium, Giardia and Trichinella. Until 2016, no standardized methods were available to detect Giardia, Cryptosporidium and Toxoplasma (oo)cysts in food. Therefore, no regulation exists regarding these biohazards. Nevertheless, considering their low infective dose, ingestion of foodstuffs contaminated by low quantities of these three parasites can lead to human infection. To evaluate the risk of protozoan parasites in food, efforts must be made towards exposure assessment to estimate the contamination along the food chain, from raw products to consumers. This requires determining: (i) the occurrence of infective protozoan (oo)cysts in foods, and (ii) the efficacy of control measures to eliminate this contamination. In order to conduct such assessments, methods for identification of viable (i.e. live) and infective parasites are required. This review describes the methods currently available to evaluate infectivity and viability of G. duodenalis cysts, Cryptosporidium spp. and T. gondii oocysts, and their potential for application in exposure assessment to determine the presence of the infective protozoa and/or to characterize the efficacy of control measures. Advantages and limits of each method are highlighted and an analytical strategy is proposed to assess exposure to these protozoa.

Tools and methods for detecting and characterizing giardia, cryptosporidium, and toxoplasma parasites in marine mollusks

Foodborne infections are of public health importance and deeply impact the global economy. Consumption of bivalve mollusks generates risk for humans because these filtering aquatic invertebrates often concentrate microbial pathogens from their environment. Among them, Giardia, Cryptosporidium, and Toxoplasma are major parasites of humans and animals that may retain their infectivity in raw or undercooked mollusks. This review aims to detail current and future tools and methods for ascertaining the load and potential infectivity of these parasites in marine bivalve mollusks, including sampling strategies, parasite extraction procedures, and their characterization by using microscopy and/or molecular techniques. Method standardization should lead to better risk assessment of mollusks as a source of these major environmental parasitic pathogens and to the development of safety regulations, similar to those existing for bacterial and viral pathogens encountered in the same mollusk species.

Randomized, double-blinded clinical trial for human norovirus inactivation in oysters by high hydrostatic pressure processing

Contamination of oysters with human noroviruses (HuNoV) constitutes a human health risk and may lead to severe economic losses in the shellfish industry. There is a need to identify a technology that can inactivate HuNoV in oysters. In this study, we conducted a randomized, double-blinded clinical trial to assess the effect of high hydrostatic pressure processing (HPP) on Norwalk virus (HuNoV genogroup I.1) inactivation in virus-seeded oysters ingested by subjects. Forty-four healthy, positive-secretor adults were divided into three study phases. Subjects in each phase were randomized into control and intervention groups. Subjects received Norwalk virus (8FIIb, 1.0 × 10(4) genomic equivalent copies) in artificially seeded oysters with or without HPP treatment (400 MPa at 25°C, 600 MPa at 6°C, or 400 MPa at 6°C for 5 min). HPP at 600 MPa, but not 400 MPa (at 6° or 25°C), completely inactivated HuNoV in seeded oysters and resulted in no HuNoV infection among these subjects, as determined by reverse transcription-PCR detection of HuNoV RNA in subjects' stool or vomitus samples. Interestingly, a white blood cell (granulocyte) shift was identified in 92% of the infected subjects and was significantly associated with infection (P = 0.0014). In summary, these data suggest that HPP is effective at inactivating HuNoV in contaminated whole oysters and suggest a potential intervention to inactivate infectious HuNoV in oysters for the commercial shellfish industry.

Development of high hydrostatic pressure in biosciences: pressure effect on biological structures and potential applications in biotechnologies

Compared to temperature, the development of pressure as a tool in the research field has emerged only recently (at the end of the XIXth century). Following several developments in Physics and Chemistry during the first half of the XXth century (in particular the synthesis of diamond in 1953-1954), high pressures were applied in Food Science, especially in Japan. The main objective was then to achieve the decontamination of foods while preserving their organoleptic properties. Now, a new step is engaged: the biological applications of high pressures, from food to pharmaceuticals and biomedical applications. This paper will focus on three main points: (i) a brief presentation of the pressure parameter and its characteristics, (ii) a description of the pressure effects on biological constituents from simple to more complex structures and (iii) a review of the different domains for which the application of high pressures is able to initiate potential developments in Biotechnologies.

The potential for marine bivalve shellfish to act as transmission vehicles for outbreaks of protozoan infections in humans: a review

Most marine molluscan bivalve shellfish feed on suspended phytoplankton which are trapped from water pumped across the gills by ciliary action. Pathogenic microorganisms in the water may be filtered by the gills during feeding, and become concentrated in the digestive glands/tract. If these pathogens are not excreted or inactivated by the shellfish, or in subsequent preparatory processes, they may be ingested by consumers, the shellfish thereby acting as vehicles of infection. The protozoan parasites Cryptosporidium spp., Giardia duodenalis and Toxoplasma gondii have the potential to be transmitted in this way, and here we review the accumulating knowledge on the occurrence and survival of the transmission stages of these parasites in shellfish, whilst also emphasising the considerable gaps in our knowledge. Relevant information is particularly lacking for T. gondii, which, in comparison with Cryptosporidium spp. and G. duodenalis, has been relatively under-researched in this context. Although it seems evident that these shellfish can accumulate and concentrate all three of these parasites from the surrounding water, whether Giardia cysts remain viable and infectious is unknown, and some evidence suggests that they may be inactivated by the shellfish. Although both Toxoplasma and Cryptosporidium apparently retain their infectivity for prolonged periods in shellfish, the actual public health threat posed by these parasites via these shellfish is unclear, largely because there is minimal evidence of infection transmission. Reasons for this apparent lack of infection transmission are discussed and it is recommended that the potential for transmission via shellfish consumption is recognised by those concerned with investigating transmission of these infections.

Effectiveness of standard UV depuration at inactivating Cryptosporidium parvum recovered from spiked Pacific oysters (Crassostrea gigas)

When filter-feeding shellfish are consumed raw, because of their ability to concentrate and store waterborne pathogens, they are being increasingly associated with human gastroenteritis and have become recognized as important pathogen vectors. In the shellfish industry, UV depuration procedures are mandatory to reduce pathogen levels prior to human consumption. However, these guidelines are based around more susceptible fecal coliforms and Salmonella spp. and do not consider Cryptosporidium spp., which have significant resistance to environmental stresses. Thus, there is an urgent need to evaluate the efficiency of standard UV depuration against the survival of Cryptosporidium recovered from shellfish. Our study found that in industrial-scale shellfish depuration treatment tanks, standard UV treatment resulted in a 13-fold inactivation of recovered, viable C. parvum oocysts from spiked (1 x 10(6) oocysts liter (-1)) Pacific oysters. Depuration at half power also significantly reduced (P < 0.05; ninefold) the number of viable oocysts recovered from oysters. While UV treatment resulted in significant reductions of recovered viable oocysts, low numbers of viable oocysts were still recovered from oysters after depuration, making their consumption when raw a public health risk. Our study highlights the need for increased periodic monitoring programs for shellfish harvesting sites, improved depuration procedures, and revised microbial quality control parameters, including Cryptosporidium assessment, to minimize the risk of cryptosporidiosis.