Introduction
In today's highly competitive business environment, traditional markets have been totally changed and companies are not working separately anymore. Companies and organizations form very wide networks by having different relationships with other members of the network. Staying in business networks offers many opportunities to companies; therefore, the use of communication and having effective activity in business networks is vital for all manufacturing and services companies and organizations.  In this research, the set of factors affecting the effective activity in the business network in Iran's food industry has been exmined.
 Methodology
The current research is a descriptive and cross-section research. The population of this research are senior and middle managers of active companies in the food industry. The sample members are 205 senior and middle managers of active food industry companies in Iran. In this research, the library method was used to collect information and a questionnaire was used to collect information to test the hypotheses. Operational definitions (questions) found in previous researches including Miller et al. (2007), Sherer (2003), Ritter and Gemunden, (2003), Bryson et al. (2003) and Philip (2011) were used to design the questionnaire. This questionnaire, which is set with a five-point Likert scale, includes two sections of general and specialized questions. In the first part, general questions include 7 questions and the second part includes 52 specialized questions. Specialized questions numbered 1 to 7 examine sharing resources, questions 8 to 11 examine common vision, questions 12 to 15 examine trust, questions 16 and 17 examine commitment, questions 18 and 19 examine choosing partners, questions 20 and 21 examine information technology, questions 22 to 41 examine network competence, questions 42 to 44 examine company flexibility and questions 45 to 52 examine effective activities. In the analysis of the collected data, descriptive statistics and structural equation model were used in the inferential statistics section, and measurement model tests and structural model tests were performed by SMART PLS software.
Results and Discussion
The results of this study show that among the eight factors of resource sharing, common vision, trust, commitment, choice of partners, information technology, flexibility of the company, competence of the network, the last two factors affect the effective activity of companies in the business network of food industry in Iran. Based on the past researches, social capital factors such as trust and commitment enable participants to effectively act together in a business network. It seems that these factors are highly ignored by active companies in the food industry in Iran.
Conclusion
According to the findings, it could be concluded that the flexibility of the companies and the competence of the network have a significant effect on the effective activity of the companies in the business network. Flexibility is defined as the ability of a company to adapt itself to the circumstances or changes. The more agile a company is, the longer it can stay in a network. In other words, the more companies can increase their flexibility, the more effectively they will be able to operate in the business network. In fact, when the environmental conditions of a company are changing, its flexibility will greatly help the continuance of the company's activity in the network. Another definition of flexibility is to respond quickly to the needs of customers. The more companies try to increase their flexibility and respond to customers' needs more effectively and faster, the stronger their relationship with their customers will be and customers will be more loyal to that company. Therefore, it is suggested to the managers of the companies to take a more serious approach to the flexibility of their company so that they can take advantage of its benefits to continue operating in a business network. Network competence includes broad concepts. One of the dimensions of network competence is the tasks specific to a company's external relations with other network members. That means, to what extent a company has the ability to create and maintain relationships. Based on this, the more a company tries to create more and more stable relationships, the competence of the network in which it operates will be higher and as a result the company activity will be more effective. Another dimension of network competence is the tasks related to relationships within a company. It means the extent to which the management of a company strives for relations between employees within the company. The more the management of the company tries to resolve the conflicts between the employees and make these relationships stronger, the higher the competence of the network will be. Another dimension that defines the competence of the network is the level of technical and economic expertise of the active companies in the network. The more the companies can strengthen these specialties in their company, the more effective their activities will be. Therefore, it is recommended to companies to establish strong relationships with other members of the network, manage the relationships between their company's employees properly and also to raise the level of technical and economic expertise of their company so that they can significantly benefit from being a member of the network.