Food Handling Practices for Apple Drying in Home Kitchens in the United States: A Survey

Inactivation of Desiccation-Resistant Salmonella on Apple Slices Following Treatment with ε-Polylysine, Sodium Bisulfate, or Peracetic Acid and Subsequent Dehydration

Salmonella is capable of surviving dehydration within various foods, such as dried fruit. Dried fruit, including apple slices, have been the subject of product recalls due to contamination with Salmonella. A study was conducted to determine the fate of Salmonella on apple slices, following immersion in three antimicrobial solutions (viz., ε-polylysine [epsilon-polylysine or EP], sodium bisulfate [SBS], or peracetic acid [PAA]), and subsequent hot air dehydration. Gala apples were aseptically cored and sliced into 0.4 cm thick rings, bisected, and inoculated with a five-strain composite of desiccation-resistant Salmonella, to a population of 8.28 log CFU/slice. Slices were then immersed for 2 min in various concentrations of antimicrobial solutions, including EP (0.005, 0.02, 0.05, and 0.1%), SBS (0.05, 0.1, 0.2, and 0.3%), PAA (18 or 42 ppm), or varying concentrations of PAA + EP, and then dehydrated at 60°C for 5 h. Salmonella populations in positive control samples (inoculated apple slices washed in sterile water) declined by 2.64 log after drying. In the present study, the inactivation of Salmonella, following EP and SBS treatments, increased with increasing concentrations, with maximum reductions of 3.87 and 6.20 log (with 0.1 and 0.3% of the two compounds, respectively). Based on preliminary studies, EP concentrations greater than 0.1% did not result in lower populations of Salmonella. Pretreatment washes with either 18 or 42 ppm of PAA inactivated Salmonella populations by 4.62 and 5.63 log, respectively, following desiccation. Combining PAA with up to 0.1% EP induced no greater population reductions of Salmonella than washing with PAA alone. The addition of EP to PAA solutions appeared to destabilize PAA concentrations, reducing its biocidal efficacy. These results may provide antimicrobial predrying treatment alternatives to promote the reduction of Salmonella during commercial or consumer hot air drying of apple slices.

Content Analysis of Food Safety Information in Apple-Drying Recipes from YouTube, Blogs, Cookbooks, and Extension Materials

Recurrent foodborne outbreaks associated with low-moisture foods prompted this study to evaluate apple-handling practices presented in apple-drying recipes available to United States consumers, and to explore the food safety implications of the recipes. Because little research is available on the safety of home fruit-drying, we conducted a systematic search of English-language apple-drying recipes from YouTube videos, blog articles, cookbooks, and university extension sources. Our evaluation found that most recipes excluded handwashing instructions, and potential cross-contamination practices were evident in 12% of the videos. Bruised or damaged apples were selected for drying in 16% of the videos, two blogs, and five cookbook recipes. Although more than half the blogs and videos demonstrated pre-treatment procedures, they did so predominantly to minimize browning with almost no mention of antimicrobial benefits. Drying temperature information was missing in 41% of the videos and 35% of the cookbooks that we evaluated. Even when temperatures were mentioned, most were insufficient for pathogen reduction according to the recommendations of previous studies. These videos, blogs, and cookbooks commonly advocated subjective indicators instead of unit measurements when slicing apples and checking for doneness. Our findings reveal the need for drastic improvements in food safety information dissemination to home apple-dryers and recipe developers.

U.S. Consumers' Tree Nut Food Safety Knowledge, Perceptions, and Handling Practices across Demographic Groups

Tree nuts are often perceived as presenting a low risk for foodborne illness, despite their association with several foodborne outbreaks and recalls in recent years. An online survey was designed to assess how consumers' food safety knowledge, perception of risks and benefits, and preferred sources for food safety information influence their tree nut handling behavior. Participants (n = 981) who soaked tree nuts or prepared nut-based dairy analogs (NBDAs) at home completed the survey. Their responses indicated insufficient knowledge about potential contaminations of tree nuts. Only 25% of participants had heard of a tree nut-related outbreak or recall. Few (30%) participants perceived a risk of contracting a foodborne illness from tree nuts. The participants were more concerned with the health benefits than potential microbial risks of raw tree nuts and preferred government agencies for tree nut food safety information. Based on a cluster analysis, demographics with lower food safety knowledge and risk perceptions (ages 18-24 or 45 and above, female, suburban and rural communities, have less than a bachelor's degree, and earned less than USD 100,000 annually) tended to engage in risky tree nut handling practices (p < 0.05). The findings of this study support the development of audience-targeted food safety extension materials for tree nuts.

Home-Drying Operation Effect on Moisture Content, Electric Energy Consumption, Ascorbic Acid, Total Polyphenol Content, and Color of Sliced "Fuji" Apples

A home dehydrator allows obtaining dried apples that are beneficial to human health, but its operations will affect the chemical and organoleptic quality of this fruit. In this study, the effect of the drying temperature and mass load of sliced fresh "Fuji" apples in a home dehydrator was evaluated with regard to moisture content, electric energy consumption, ascorbic acid, total polyphenol content, and color of the dried fruit. Fresh "Fuji" apples were cut to obtain a uniform slice with a thickness of 4 mm and diameter from 60 to 75 mm. A home dehydrator was operated at 50 and 70°C (nominal temperatures), with a total sliced apple load of 250 and 500 g, uniformly distributed in five trays. Drying was carried out for 7 hours, and every hour, the trays were rotated, changing their position from the top to the bottom. Only the middle tray was always kept in the same position. As result, the level of nominal temperature (50/70°C) was not reached for any of the trays, regardless of the mass load (250/500 g) in the home dehydrator. The temperature average for fruits dried in trays of the home dehydrator that were rotated (top and bottom) and kept in the same position (middle) did not differ (p > 0.05) among them. At the end of drying, the apple treatment at 50°C/250 g, 50°C/500 g, 70°C/250 g, and 70°C/500 g reached 23.1, 26.2, 4.3, and 4.5% (w.b.), respectively. The drying conditions at nominal 50°C favored the quality of the dried sliced apples with regard to ascorbic acid and total polyphenol content; however, the treatment at nominal 70°C produced less variation in color with respect to the fresh fruit. The home dehydrator allowed obtaining sliced dried "Fuji" apples that adequately preserve the ascorbic acid, total polyphenol, and color with respect to the fresh fruit.

U.S. Consumer Practices of Homemade Nut-based Dairy Analogs and Soaked Nuts

Tree nuts, a low-moisture food, are typically perceived as being a low risk for foodborne illness. In the past five decades, the consumption of tree nuts (dry, soaked, or as nut-based dairy analogs [NBDA]) has increased along with corresponding foodborne illness outbreaks and recalls associated with these products. We developed an online survey to assess tree nut handling practices of U.S. consumers, and to select study participants who have soaked tree nuts and/or made NBDA at home. We distributed our initial survey questions in October 2021 to a convenience sample (n = 12) to test for clarity and comprehension. In January 2022, participants (n = 981) who met the criteria completed the survey. The most popular soaked tree nuts were almonds (54%), followed by cashews (36%), walnuts (32%), and pistachios (22%). Participants soaked tree nuts for direct consumption (67%) and during the preparation of NBDA (80%). Participants soaked tree nuts under refrigerated conditions for 1-24 h (22%), on the countertop at room temperature (est. 65-75°F [18-24°C]) for 1-5 h (21%), or at room temperature for 12 h or more (6%); 16% used a hot or boiling water, short time treatment. Some participants added acid (28%) or salt (25%) to the soaking water. Among those participants who dried their tree nuts after soaking (63%), 89% reported drying at a temperature lower than 46°C (115°F). Some participants (34%) used their tree nuts to make fermented dairy analogs (e.g., "cheese" or "yogurt") by adding "probiotics" (56-86%) or a yogurt starter culture (37-99%), respectively, and then, most frequently, holding at or below 20°C (68°F) for 12 h or less (29%). The safety of many of these practices has not been adequately investigated, but the findings of this study will inform future risk assessment and risk modeling studies on tree nut food safety in home kitchen settings.