This study was conducted as a cross-sectional survey using an internet panel survey company (Macromill Inc) and all participants were registered with the company. First, to recruit study participants, the survey company randomly sampled a list of registered participants between the ages of 15 and 79 years. Second, an email was sent to everyone on the list to inquire whether they were interested in participating in this study. Enrollment closed when the number of participants in each group by gender and age in 10-year increments reached the target sample size (103 people per group). Participants completed the survey via a web survey screen and received a small monetary reward upon survey completion. There were 1442 participants in the study; after data cleaning, 1414 participants were included in the analysis with 706 men and 708 women.

Although the Japanese population has a higher number of people in their 70s than in their 20s, all age/sex groups had an equal number of respondents in this study owing to the method used to enroll participants. We did not employ data augmentation methods because we used traditional statistical methods for the analysis. Regarding regions, there was a slightly higher number of respondents in the city prefectures of Kanto and Kansai than in other areas. The respondents’ incomes were categorized in ranges: the median household income of the respondents was 6-8 million yen (100 yen=US $0.9596), which is higher than the national median household income of 4.4 million yen.

Age, gender, weight, height, and region of residence were recorded when the participants first registered with the panel survey company.

In addition to items related to food safety, food hygiene, and food defense, the survey included questions about the participants’ personalities (self-evaluation) and lifestyles (what they considered important when purchasing electrical appliances and clothes).

The value of food hygiene and food defense was evaluated using the contingent valuation method (CVM). There were six questions each pertaining to the specific additional costs to be paid for food hygiene measures (Q27) and for food defense measures (Q28) for a total of 12 questions. The unit prices of several food products were provided as examples, and the respondents were asked how much extra they would be willing to pay for food hygiene or food defense measures to be incorporated. The relevant questions are presented in Textbox 1. The unit price is expressed in Japanese yen, and the exchange rate at the time of the survey, January 2021, was 100 yen=US $0.9596.

We performed a distribution check on the payment amount for additional costs for food defense. As many people answered “0 yen” (not willing to pay), we performed comprehensive univariate logistic regression analyses for all combinations of the 12 objective variables and other questionnaire items as explanatory variables to analyze the characteristics of this subgroup. The univariate logistic regression analysis variable was evaluated using z-scores. By averaging the z-scores for the 12 questions (Textbox 1), we considered the strength of the relationship between the other questions and willingness to pay. The z-scores of the 12 logistic regression analyses, which changed the objective variable, were averaged and arranged in order of absolute values of the average of z-scores. The z-score is a statistic affected by sampling and therefore has small variation owing to sampling, whereas large fluctuations are unlikely. In this study, the responses to the 12 similar questions were converted to binary values and logistic regression was performed with the converted values as the objective variables. Given the slight variation in z-scores among the 12 logistic regression analyses, evaluating the 12 z-scores individually was not required and comparisons were made using mean values.

Since our questions concerned amounts of money, the data distribution was often skewed to the right (positive skewness). In the case of such a distribution, a transformation is often implemented to ensure that the distribution is closer to a normal distribution. As the Box-Cox transformation cannot be defined for 0, we added 1 to the transformation so that the distribution shape would follow a normal distribution. Since λ was estimated to be approximately 0 for each variable, we set λ=0 for all 12 variables. In other words, a logarithmic transformation was performed. Next, principal component analysis was performed on the 12 variables after the Box-Cox transformation and a principal component score was calculated for each respondent.

Univariate linear regression analyses were performed for all combinations with the top three principal component scores as the objective variables and all questionnaire items not used in the principal component analysis as the explanatory variables. Consequently, items that had strong relationships were identified. The relationships between each principal component score and the questionnaire items were examined.

This study was conducted with approval of the Ethics Committee of the National Institute of Public Health, Japan (approval number NIPH-IBRA#12302). All participants provided informed consent online for data collection and storage. Informed consent for participation in the study was obtained at the time of registration. In cases where participants were under the age of 18 years, a consent screen was displayed to obtain permission from their parents or guardians. The web-based questionnaire survey was conducted by an authorized research company compliant with personal information protection and we obtained anonymized data from the company.

In this study, a web-based survey was conducted in Japan to examine people’s willingness to pay for food safety and food defense. Approximately one-third of the respondents stated that they were unwilling to incur any additional costs. This subgroup also reported their willingness to consume food items included in their delivery even if those items were not part of their original order.

To analyze the additional amount paid, principal component analyses were performed. The first principal component reflected whether one is willing to pay extra and if so, how much. This propensity was maintained even if individual foods and amounts of money differed and therefore does not need to be discussed further. However, the second principal component reflected an axis indicating a difference in the importance of food defense and food hygiene among respondents.

Individuals who expressed unwillingness to pay additional costs for food hygiene and food defense may perceive bearing the costs associated with ensuring food safety as the responsibility of businesses rather than that of consumers. The first principal component represented the amount paid, and many items strongly associated with this component were related to perceptions of safety. Some people may consider food safety as something that should be provided free of charge, whereas others are willing to pay for it.

Respondents who were unwilling to pay for additional costs were often those who would consume food included in their delivery even if it posed a risk of intentional harm. Therefore, it can be concluded that this type of respondent is less concerned about food safety. The third principal component reflected the influence of the original price. Few people indicated that they would pay a fixed amount higher than 0 yen, regardless of the product’s price. Those who claimed that the price would not affect their decision may also be considered in the 0 yen category; in other words, they have no intention of spending additional money. Consequently, it can be inferred that Japanese food is perceived as safe and trustworthy [2], and respondents with this perception do not intend to increase their expenditure.

Some individuals in Japan believe that investing in safety is unnecessary. For example, Japan’s tap water is inexpensive and suitable for drinking, and it is considered a safe country overall [14]. In 1970, Yamamoto (writing under the pseudonym Isaiah BenDasan) [15] astutely pointed out that “Japanese people think water and safety are free.” Despite this perspective, citizens do pay for water and contribute through taxes for police services. Owing to the relatively low cost and its integration with other needs, there is a high possibility that some citizens are unaware of the necessity of investing in safety.

In Japan, both food defense and food hygiene are crucial for ensuring safe and high-quality food. Food defense involves protecting food from intentional contamination, whereas food hygiene focuses on preventing unintentional contamination. Although government regulations strictly establish standards for food hygiene, guidelines for food defense are developed and published by a research team funded by the Ministry of Health, Labour, and Welfare’s scientific research grant [1,3]. In recent years, concerns have arisen regarding the intentional contamination of food products with foreign substances in Japan. Consequently, stronger food defense measures are required, and the industry is working toward addressing these issues and promoting greater transparency and traceability in the food supply chain.

Thorough measures to improve food safety in the food supply chain have become imperative recently [16,17]. As all factors at each stage of the food chain, from primary production to consumers, can affect food safety, necessary actions must be taken [18,19]. To mitigate the risk of food-related health hazards, both businesses involved in the food supply chain as well as consumers must adopt appropriate measures.

Overall, Japan has fostered a strong food safety culture and remains committed to ensuring citizen health and well-being through safe and nutritious food. However, the results of this survey indicate that some consumers may be unaware that maintaining Japan’s robust food safety culture, built over many years, may entail a financial burden.

The second principal component revealed an axis that distinguishes between food hygiene and food defense. The most important factor indicating this distinction was “When buying food, the following are important to you: reputation (word of mouth).” The second most important factor was “When buying clothes, the following are important to you: price.” The fifth most important factor was “When buying food, the following are important to you: brand.” Based on these results, the second most important factor, “clothing,” is not directly related to food, whereas the fifth factor, “brand,” emphasizes the value of intangible qualities. The value of a brand has also been demonstrated by Aaker [20] and Winters [21].

In the case of agricultural products, Koike et al [22] conducted an internet survey and found that 64.5% of consumers preferred domestically produced agricultural products, 35.2% had no specific preference, and only 0.3% preferred foreign-produced products. This indicates the existence of the “domestic myth” (an emotional belief that domestic production is superior) or the perception that food produced in Japan is inherently safe, particularly regarding agricultural products. In our study’s questionnaire, most respondents stated that domestic production is important when purchasing food because “domestic products are trusted by many people.” Additionally, individuals who value brands in contexts other than food, such as clothing, also support food defense. We asked respondents whether they considered “manufactured domestically” to be important when buying food, with 1.3% responding “strongly disagree,” 2.9% responding “disagree,” 10.9% responding “somewhat disagree,” 33.5% responding “somewhat agree,” 31.2% responding “agree,” and 20.2% responding “strongly agree.” This indicates that the “domestic myth” of domestic production is prevalent in the food industry in Japan as 84.9% of respondents answered “somewhat agree” or higher. Our findings suggest that food hygiene is well-managed and recognized in Japan, while food defense is considered an added value, similar to brands.

We intend to investigate causal relationships and other factors using analysis methods such as structural equation modeling to identify the type of consciousness the current result is based on.

Several limitations to this study must be acknowledged. First, the data were collected only from respondents registered with an internet panel survey company, which may have biased the sample. Older people who use computers and the internet may be healthier and more active than those who do not. However, panel surveys are increasingly widely used in questionnaires [5,23-26]. Second, respondents received a brief description of the survey via email and then chose whether to participate in the survey. Thus, there is a possibility of participant bias owing to their preferences. Third, we included an explanation of food defense in our survey because we thought that the concept of food defense was not well understood by the general public. In the future, we must clarify the difference between food defense and food hygiene and then ask the participants to respond. This may have affected some participants’ responses regarding food defense. Fourth, this was not a population-based study; therefore, the participants may not be representative of the general population in Japan. Fifth, participants received a small cash reward for their participation, which may have affected the randomness of the sample. However, the research firm minimized bias by using a large enrollment population to create the survey panel (the total number of people registered with the research firm was more than 1,300,000, accounting for approximately 1% of the Japanese population). Despite these limitations, internet questionnaires can be considered representative of the general public; therefore, we believe that the study results could represent the entire Japanese population to some extent.

Approximately one-third of respondents said they were unwilling to incur additional costs for ensuring food safety. This subgroup also described that they would eat foods included in their delivery that they had not ordered. We performed a principal component analysis on the amount of additional money that people were willing to pay for food defense and food hygiene measures, and found an axis that indicated the divergent importance of food defense and food hygiene for consumers.

In Japan, food hygiene is taken for granted and food defense is considered of little significance by many people; it is only considered important by those who seek to gain peace of mind. Many companies are applying food defense efforts, but it is necessary to also educate consumers so that they understand the need for these measures.