Doris T. Hicks

Effect of high hydrostatic pressure on four genotypes of F‐specific RNA bacteriophages

Aims:  The pressure responses of four genotypes of F‐specific RNA bacteriophages, f2, GA, Qβ and SP, were evaluated with respect to pressure magnitude, treatment temperature and suspending medium.

Pressure Inactivation of Enteric Viruses in a Seafood Salad-Like Product

High pressure processing (HPP) is a nonthermal processing technology that can inactivate foodborne viruses. This study assessed the protective effects of food components on virus inactivation by HPP in a seafood salad model. Virus-inoculated seafood samples (cod, shrimp, tuna, and clams) with or without mayonnaise were pressure-treated at 5°C. The seafood salad provided a protective effect on HPP inactivation compared to cell culture medium. Inactivation in seafood salad varied greatly due to the complex nature of the food matrix. When seafood salad ingredients were isolated, mayonnaise alone had a 2.0-log10 PFU/g protective effect for all viruses, unlike albumin, which did not affect virus inactivation, providing some insight into the roles individual ingredients may play on HPP inactivation of viruses in foods.

Assessing Knowledge and Attitudes of U.S. Healthcare Providers about Benefits and Risks of Consuming Seafood

An online needs assessment survey of healthcare providers was developed and implemented to determine knowledge and attitudes about the benefits and risks of consuming seafood along with how this might impact patient/clientele counseling. Only 6 of the 45 knowledge items queried (13%) met the 80% subject mastery or proficiency with a total knowledge score of 56 ± 18%. Based on this survey, it was found that healthcare providers were less than proficient regarding all knowledge areas for seafood. Understanding of seafood safety and contaminants was low. In addition, while the majority (76%) of healthcare respondents knew the correct recommendation for seafood meals per week, they failed to identify the groups that were targeted by the Food and Drug Administration/Environmental Protection Agency (FDA/EPA) advisory about seafood and mercury and therefore could be providing inaccurate information. Attitudinal responses for 18 items resulted in an overall average score of 3.28 ± 0.47 meaning slightly agree (based on a 5-point Likert scale strongly disagree—strongly agree). While trends showed that it was important to the respondents to provide accurate information (3.78 ± 1.06) about seafood to their patients, they felt more comfortable recommending that their patients follow government advice (3.52 ± 0.91) about both seafood safety and which seafood to eat over other sources. Combined with a low knowledge base, attitudinal responses indicate that there could be a barrier to both outreach education to these healthcare providers and to their patient counseling regarding seafood consumption. Results also showed that a combination of online, science-based, easy to access information with the capability to provide brochure-formatted information would appear to be the best way to communicate seafood safety, nutrition, and health information.

Thermal inactivation of human norovirus surrogates in oyster homogenate

Human norovirus (HNV) is the most frequent causative agent of foodborne diseases in the US. Raw and undercooked oysters are commonly associated with outbreaks caused by HNV. Many guidelines recommend that shucked oysters be boiled for at least 3 min, but it is not clear this thermal treatment can inactivate HNV. The objective of this research was to evaluate whether this recommendation was sufficient to inactivate two HNV surrogates, murine norovirus (MNV-1) and Tulane virus (TV) in oyster homogenate as well as to determine their thermal inactivation kinetics. Inoculated oyster homogenate was heated in boiling water and circulating water bath at 49 to 67 °C for different time durations. After 3 min of boiling, both MNV-1 and TV titers decreased to below the detection limits. First-order model and Weibull model were used to describe thermal inactivation kinetics. TD = 1 values from Weibull mode are used as an analog to D values in first-order model. The D values of MNV-1 and TD = 1 values ranged from 28.17 to 0.88 min and 26.64 to 0.78 min at 49 to 67 °C, respectively. The D values of TV and TD = 1 values ranged from 18.18 to 1.56 min and 19.35 to 1.56 min at 49 to 63 °C, respectively. The kinetics demonstrated that at temperatures > 58 °C, TV was much more heat sensitive than MNV-1. As the temperature increased over 58 °C, the inactivation of both viruses occurred at a faster rate. Boiling treatment for 3 min as recommended by FDA for cooking shucked oysters, inactivated MNV-1 and TV in oyster homogenate below detection limit. One minute heating of TV at 63 °C or MNV-1 at 67 °C in contaminated oyster homogenate reduced the viral titers below the detection limits. Our research identified effective combinations of time and temperature to inactivate two HNV surrogate viruses, and thus provides insights on thermal processing to reduce the risk of foodborne viral illness outbreaks associated with consumption of oysters.