Health is what human beings want, and the cognition and definition of health are constantly changing over time. Traditionally, health usually refers to the absence of disease, and illness means unhealthy. However, the World Health Organization pointed out in 1948 that health was not a single, clear goal, and it was a complete good state of the body, mind, and society, not just an exemption from disease or weakness. Health awareness is a mental state of individuals’ self-recognition of health, which is suitable for assessing the tendency of individuals to adopt healthy behavior, representing the orientation of healthy lifestyles. Under normal circumstances, individuals with high health awareness pay more attention to their own health and have higher motivations to adopt healthy behavior. At the same time, health awareness can affect the health information process of consumers, and consumers with high health awareness have higher motivations to process relevant information [23]. Studies have shown that health awareness has a significant impact on health-related attitudes and behaviors. In terms of food choices, groups with high health awareness prefer to eat functional foods.

Health awareness is divided into four dimensions, namely, health self-awareness, health alertness, health self-monitoring, and health participation [13]. Based on existing research and the characteristics of the research objectives, this paper divided consumer health awareness into three dimensions: the first dimension is health change perception, which refers to consumers’ comparative understanding of their own health perception before and after the outbreak of COVID-19 based on the time dimension, objectively reflecting the perception of physical health changes of consumers [24]; the second dimension is health concern, which refers to whether individual physiological functions caused by external conditions, living environment, personality, and other factors continue to be in good condition, reflecting the degree of consumers’ attention to their own health after the outbreak; the third dimension is healthy habit development, which refers to the development of healthy living habits by consumers before and after the outbreak. The dynamic changes reflect whether consumers can maintain healthy living habits for a long time.

It needs to be emphasized that the reason why consumers’ health awareness can be linked with dairy product purchase behavior is that dairy products are of great significance to human health. On the one hand, dairy products can provide the human body with rich nutrients; on the other hand, rich protein, active peptides, and other substances in dairy products have significant regulatory effects on humans under the same thermal energy intake condition, thus leading to better body immunity with a more obvious effect.

Therefore, the impact mechanism of consumer health awareness on dairy product purchase behavior can be specifically analyzed from the three dimensions of health awareness: First of all, in terms of health change perception, individual behavior is not only affected by information but also regulated by health cognition according to the protection motivation theory (PMT) analysis. Individuals adopt different coping modes or behaviors according to different cognitions. After the outbreak of COVID-19, the health of consumers was seriously threatened. Consumers with high health awareness understand and know their own health status and changes so that they may be more proactive in maintaining and improving their own health status. The simplest and most important method is to improve human immunity through dietary improvement so that people may be more willing to buy dairy products. Secondly, in terms of health concern, individuals with a higher degree of health concern are more sensitive to changes in the external environment according to the idea of continuous attention theory (CFT). Faced with the impact of COVID-19, the self-protection awareness of people is constantly increasing, and the degree of attention to their own health is also significantly increased. Therefore, the motivation of consumers to buy dairy products may be out of consideration for the health of themselves and their families. That is, the higher the health concern of consumers is, the greater the purchasing power of dairy products is. Finally, in terms of habit development, reinforcements are necessary to the establishment and formation of any new behavior according to the theory of habit formation (HFT), and repetitive actions of reinforcements would promote the generation, development, improvement, and consolidation of new behavior. COVID-19 is a public health emergency. Although the country has used the shortest time to suppress its spread, the normalization of epidemic prevention and control will be a long process, and this long process will also promote the health habits of consumers. The development of dairy products will increase purchase intention of dairy products and further affect the purchase behavior. The theoretical framework of this paper is constructed through the above theories, as shown in Figure 1.

On the whole, 79% of the surveyed 1780 consumers are more willing to buy dairy products after the COVID-19 outbreak, and the proportion of purchased dairy products is higher than that before the outbreak, with an average increase of 17.49%. In order to further test the impact of consumer health awareness on the dairy product purchase behavior under the impact of COVID-19, this paper weights and averages the specific indicators under the three dimensions, such as health change perception, health concern degree, and health habit development. To facilitate the expected statistical analysis and empirical analysis, the weighted average value is further processed by assigning a value of 1 to 3. Specifically, the value is assigned to “1 = smaller” when the weighted average of each dimension index is between 1 and 2 (inclusive), and the value is assigned to “2 = normal ”, when each dimension index is between 2 and 4 (exclusive), and the value is assigned to “3 = larger”, when each dimension index is between 4 (inclusive) and 5. From the cross-statistical results of independent variables and dependent variable, consumer purchase intention and purchase behavior show certain differences between groups after grouping. From the perspective of the overall changes in consumer health awareness, 66.67% of those with less health concern degree are more willing to buy dairy products, with an average increase in the purchase proportion of 8.93%, and 90.72% of those with greater health concern degree are more willing to buy dairy products with the increased proportion by 27.46%; 61.54% of those who are less concerned about health are more willing to buy dairy products. The average increase in the purchase proportion is 3.13%. A total of 85.33% of those who are more concerned about health are more willing to buy dairy products. The average increase in purchase proportion is 21.43%. A total of 56.46% of those with less healthy habits are more willing to buy dairy products, with an average increase in purchase proportion of 8.47%, 87.89% with better healthy habits are more willing to purchase dairy products, with an average increase in purchase proportion of 22.81%. Although there are differences in the linear ratios between the changes in various dimensions of consumer health awareness and the changes in purchase intention and purchase behavior, to a certain extent, it can be initially found that higher health change perception, health concern degree, and health habit development leads to stronger purchase intention and higher increase of purchase proportion (Table 1).

This paper uses Stata 14.0 statistical analysis software to estimate the Heckman two-stage model and empirically examines the impacts of consumer health awareness on dairy products purchase behavior under the impact of COVID-19. Model (1) is a benchmark model regression, which mainly incorporates individual characteristics of consumers, family endowments, and market environment characteristics into the model for benchmark testing. Taking the impact of health awareness on dairy product purchase behavior into account, three sets of core explanatory variables, health change perception, health concern degree, and health habit development, are included in Model (2). The specific regression results are shown in Table 2. According to the regression results, it can be found that the inverse Mills ratio has passed the significance test in both Model (1) and Model (2), indicating a sample selection bias. The Heckman two-stage model can effectively solve this problem when this paper focuses on the impact of consumer health awareness on dairy product purchase behavior. Results analysis can be conducted based on Model (2).

For the impact of consumer health awareness on dairy product purchase behavior, health change perception has passed the significance test at the level of 1% in both the first and second stages, and the coefficient symbol is positive, which means the stronger health change perception of consumers is, the stronger the willingness to buy dairy products, and the higher the proportion of purchased dairy products is. It can be explained as follows: after the COVID-19 outbreak, more consumers can perceive changes of their health conditions, and they will pay more attention to their own nutrition. The balance of dairy products will increase nutrient intake accordingly, thus leading to the increase of purchase intention and purchase proportion. Health concern degree passes the significance test at the 1% level in the second stage, and the sign of the coefficient is positive. That is, the more consumers that pay attention to their health, the proportion of dairy products purchased would increase accordingly. This can be explained by the fact that COVID-19 has a huge impact on consumers’ psychology. More people realize the importance of disease prevention and physical health, and they will continue to pay more attention to health to improve their immunity through the ingestion of nutrients. Although dairy products have no medicinal function, their benefits to human health have been proven. Therefore, the increased attention of consumers will help increase the proportion of dairy products they buy. Health habit development passes the significance test at the 1% level in both the first and second stages, and the coefficient symbol is positive. That is, the higher degree of health habit development is, the stronger the purchase intention is. Meanwhile, the proportion of purchased dairy products can also increase. This observation can be explained as follows: dairy products, as a “vegetable basket” product of the national economy, are a standing consumer product in most households. Many households have the habit of drinking liquid milk and eating dry dairy products for a long time. A step-by-step improvement of health habit development will strengthen the purchase intention and increase the purchase proportion. In summary, consumer health awareness has a significantly positive impact on dairy product purchase behavior.

As for other factors that affect consumer dairy product purchase behavior, age negatively affects dairy product purchase behavior. It can be explained by the fact that older consumers have lower drinking and eating preferences for dairy products than younger consumers. The increase in the purchase proportion would also be lower than that of younger consumers. The level of education positively affects the purchase willingness significantly. The higher the education level of consumers is, the stronger awareness of the rich nutritional value of dairy products is, and the stronger purchase intention for dairy products is. The number in the household has a significantly negative effect on the purchase willingness. The larger the household population is, the weaker willingness to buy dairy products is. This may differ from previous studies, which theoretically suggest that the higher the number of household members is, the higher the demand for dairy products in the household is, and the corresponding higher the willingness to purchase is. In order to explore the source of this contradiction, we conducted partial telephone callbacks to respondents with a household size of more than five and learned that there is a significant difference in the demand preference for dairy products due to higher household size, which increases the difficulty of purchasing dairy products and for this reason reduces the willingness to purchase. The elderly and children significantly and positively affect the willingness to buy dairy products. When the epidemic occurred, the elderly and children became the key groups to pay attention to. If there are elderly or children in the family, more attention should be paid to the nutritional balance in daily life, so the purchase intention of dairy products will be stronger. Changes in household income significantly and positively affect purchase intention. Income is the basis of consumption, and income level affects consumers’ willingness to buy to a certain extent. Therefore, if the income level increases after the outbreak, the willingness to buy dairy products will also be correspondingly promoted. Settlement sites negatively affect purchase intention. That is, compared with cities, rural residents are more willing to buy dairy products after the outbreak. The survey found that due to less going out under the epidemic, the awareness of rural residents has increased significantly, so that it may significantly increase their willingness to buy dairy products. Quality and safety concerns significantly and negatively affect the purchase behavior for dairy products. Dairy product quality and safety incidents will seriously affect purchase behavior. When consumers pay more attention to the quality and safety of dairy products, it is easier to inhibit the increase in the purchase proportion of dairy products. Satisfaction with quality supervision has a significantly positive impact on dairy product purchase intention and purchase behavior. That is, the more satisfied consumers are with the current quality supervision, the stronger purchase intention they will have to buy dairy products; at the same time, the purchase proportion of dairy products will increase. Consumption convenience significantly and positively affects the willingness to purchase dairy products; that is, better consumption convenience contributes to increased purchase intention for dairy products. These variables are consistent with the findings of previous studies and will not be discussed too much here (Table 2).

According to the above statistical description and empirical tests, it can be concluded that consumer health awareness has a significantly positive effect on dairy product purchase behavior. In order to further analyze the impact of health awareness on dairy product purchase behavior among different groups of consumers, considering an empirical test, this paper divides consumers into groups based on health change perception, health concern degree, and health habit development. The groups with values of “1” and “2” are classified as low health awareness groups, and those with a value of “3” are assigned to the high health awareness group. The Heckman two-stage model is also adopted to estimate the impact of health awareness on the purchase of dairy products among different groups of consumers to test the group differences.

Table 3 shows the test results of group differences based on health change perception. For consumers with low health change perception, gender and education levels significantly and positively affects dairy purchase behavior. For consumers with high health change perception, quality and safety attention significantly and negatively affect dairy product purchase behavior, and quality supervision satisfaction significantly and positively affect dairy product purchase behavior. In general, consumers with low health change perception are more susceptible to the influence of gender and education on purchase behavior of dairy products, and consumers with high health change perception are more likely to be affected by the quality and safety concerns and satisfaction with quality supervision. Therefore, it further illustrates that consumers with different degrees of health change perception after the outbreak of COVID-19 have certain differences in the purchase behavior of dairy products.

The results of the group differences based on the degree of health concern are shown in Table 4. For consumers with a low health concern degree, the level of education has a significantly positive impact on the purchase behavior for dairy products, and the number in the household has a significantly negative impact on the purchase behavior for dairy products. For the group with high health concern degree, satisfaction with quality supervision has a significantly positive impact on dairy product purchase behavior, while education level and quality and safety concern have significantly negative impacts on dairy product purchase behavior. In general, both the low health concern group and the high health concern group are easily affected by the level of education, but the education level differs in the direction of the impact effect between the low and high health concern groups. At the same time, the dairy product purchase behavior of consumers in the low health concern group is also vulnerable to the influence of the family population, and the high health concern group is also affected by the quality and safety concern and the satisfaction of quality supervision. It can be seen that after the outbreak of the epidemic, consumers with different levels of health concern showed certain differences between groups in their purchase behavior of dairy products.