Effects of Elevated Hydrostatic Pressure against Mesophilic Background Microflora and Habituated Salmonella Serovars in Orange Juice
Introduction
Foodborne diseases can affect healthy individuals and more severely at-risk groups such as the very young, the elderly, pregnant women, and the immunocompromised [1]. It is estimated that around 30% of US population are currently considered as at-risk individuals for foodborne diseases [2]. Foodborne Salmonella infections are a major public health concern in the country and around the globe. From 1998 to 2016 more than 2500 foodborne outbreaks in the United States were associated with Salmonella serovars, leading to about 6900 cases of illnesses and >7900 hospitalization episodes [3].
Active surveillance data of the Centers for Disease Control and Prevention (CDC) indicates around 42,000 laboratory confirmed cases of non-typhoidal salmonellosis occur every year in the United States, with 94% of cases associated with contaminated food products, and leading to hospitalization in 27% of cases. Considering the unreported and under-diagnosed cases, CDC further estimates that non-typhoidal Salmonella serovars are responsible for 644,786 to 1,679,667 cases of foodborne illnesses resulting in 8545 to 37,490 annual episodes of hospitalization in the United States [4]. The bacterium is currently considered as the leading etiological agents of foodborne hospitalizations and deaths in the United States [4]. In addition to illness, hospitalization, and death episodes, many survivors of salmonellosis suffer long-term health complications such as reactive arthritis and post-infectious irritable bowel syndrome. Considering these health complications, captured in public health metrics such as Disability-Adjusted Life Years (DALYs), Salmonella serovars are the top-ranked pathogen of concern among major foodborne diseases [5].
The number of Salmonella outbreaks associated with contaminated fruits, vegetables, and juices have been increasing in recent years and have been a rising concern in public health since the early 1990s [6]. In response to these issues, the U.S. Food and Drug Administration (FDA) introduced regulations [7] which mandate that all 100% fruit/vegetable juices sold wholesale need to be produced under a Hazard Analysis and Critical Control Point (HACCP) plan. The regulation also requires processors to administer a treatment that results in at least a 5-log reduction of the most resistant microorganism of public health significance that are likely to occur in juices. Presently, Salmonella is commonly accepted as the pertinent pathogen that occurs in citrus juices [8]. In 1999, 2000, and 2005 there have been three multi-state outbreaks of Salmonella associated with orange juice in the United States [3]. Similar outbreaks in other countries such as India, Australia, Canada and South Africa had also been reported in the literature [8]. Various Salmonella serovars could survive up to 25 days in orange juice after manufacturing if product is untreated or not validated to inactivate the pathogen [9].
Emerging technologies have been investigated to replace or complement conventional interventions employed in food processing to prevent and eliminate foodborne diseases episodes and assure health of the public [10]. Although it had been target of research in academia for several decades [11], application of high pressure processing in food manufacturing had been gaining increasing momentum in recent years due to advances in engineering of commercially available units [10]. Currently, more than 100 different food products around the world are brought to market using this emerging technology [12], and in the United States the market size of pressure treated products are estimated to surpass $9B annually [13]. The technology is emerging response of the private industry for manufacturing of products with clean label, extended shelf-life, and fresh-like qualities some of the major demands of consumers in 21st century [10]. The National Advisory Committee on Microbiological Criteria for Foods (NACMCF) has therefore recommended that pasteurization be redefined, and high pressure processing has been recommended for the supplementary non-thermal pasteurization [14].
Considering the public health significance of Salmonellosis, and repeated involvement of juices in sporadic and outbreak foodborne disease episodes, the objective of this investigation is to conduct a laboratory challenge study for inactivation of Salmonella serovars and mesophilic background microflora in orange juice exposed to various time and intensity levels of elevated hydrostatic pressure for validating a safe, feasible, and efficacious decontamination hurdle in manufacturing.