One misconception about socially responsible investing is that it limits the investing universe to renewable-energy companies and organic-food retailers. However, that's not the case. Outlined below are a few companies that stand out by being socially responsible business and successful investments that should continue to shine in the future.

Costco Wholesale Corporation (NASDAQ:COST) does not go to great lengths to push and promote corporate social responsibility, or CSR, but CSR is nonetheless the company's modus operandi. The company's code of ethics is simple yet clear: Take care of members, employees, and suppliers and obey the law . Evidence of the first guideline is the loyalty of its workforce, which owes to Costco's corporate culture. Employee benefits include health and dental care for almost all workers, one of the highest pay rates in an industry known for low margins, and career growth opportunities. Beyond this, employees have a sense of pride when coming into work, which translates to lower employee turnover and higher productivity.

The company is socially conscious, focusing its philanthropic efforts on children, education, and social services, which ultimately affects the communities around it. From an environmental perspective, the warehouse giant has focused on reducing its environmental footprint by recycling cardboard, constructing its warehouses from 80% recycled steel, and reducing the amount of plastic used in packaging, which in turn translates to lower costs.

The company operates more than 600 membership warehouses across four continents. Its industry peers are Sam's Club, privately held BJ's Wholesale Club, and PriceSmart. Its membership renewal rate of 90% in the U.S. and Canada indicates strong brand loyalty to a range of products from own-brand Kirkland toilet paper to big-ticket items like diamond engagement rings. The company operates conservative financials and expands with caution, and the current CEO continues to operate in a similar leadership style as co-founder Jim Sinegal, which instils consistency.

Colgate-Palmolive Company (NYSE:CL) has organized its efforts toward sustainability into the broad categories of "people, performance, and plant." The consumer goods giant matches people's donations to various charities through its Annual Giving Campaign. It abides by good corporate-governance policies, ensuring independence and transparency, and a clear code of conduct that covers the practices of employees and auditors. Finally, its environmental initiatives include reducing its manufacturing carbon footprint by 20% from 2005 to 2015, being more conscious of the distribution of its products, and helping increase access to clean water in South Africa for local communities.

As a result of these continued efforts, the company ranked in the top 10 on the 2013 CSR RepTrak 100. This is a list compiled by The Reputation Institute (link opens PDF), a reputation-based management-consulting firm that ranks the world's most reputable companies by CSR. Additionally, Colgate is also included in Ethisphere magazine's list of the world's most ethical companies.

Colgate-Palmolive is categorized as a secular company, meaning its growth remains consistent in any economy, which makes it a classic example of a recession-proof stock. Its ultra-low beta of 0.44 means the stock has mimicked the broader market over the past five years, returning just more than 100%, so its mention at cocktail parties is nonexistent. While that does sound disappointing, the world leader in oral care has consistently raised its dividend every four quarters since 2005, and even every two quarters now in a few instances. Its easy-to-understand business, low volatility, and consistent performance warrant it a position in any long-term portfolio.

Whole Foods Market (NASDAQ:WFM) is in a sector that is experiencing growth on the basis of a long-term trend: consumers' increased consciousness of both healthy eating habits and the production processes involved in preparing food. Conscious capitalism, as outlined by Whole Foods founder John Mackey, is based on his thesis that companies and human beings should be aware of the effects their practices have on other stakeholders and the environment. Being the CEO of one of the most prominent organic-foods supermarkets, he has been able to increase his influence in socially responsible investing. The Harvard Business Review blog supports the idea that companies that adhere to not-just-for-profit business models outperform the S&P 500 index by a "factor of 10.5 over the years 1996-2011," and over the past decade, Whole Foods has performed accordingly.

During the latest quarter, the company experienced lower comparable-store sales growth of 5.9% and lowered its financial guidance for the coming year. Increased competition from Sprouts Farmers Market and The Fresh Market has been the company's main cause of concern. As a result of the recent quarterly earnings and forward guidance, the stock has fallen from its all-time high achieved in October, but I believe this makes for a good opportunity to purchase shares in this retailer. As expansion continues, consumers become more affluent and conscious of their health, while the company maintains its strengths and the values it was built upon.

Bottom line
These are a few examples of socially conscious investments and should act as a starting point for further research. If a company is ethical and socially responsible, that does not warrant an investment, but it should narrow down the companies worthy of your consideration. Searching through the holdings of socially responsible exchange-traded funds should provide another avenue for sifting through mass amounts of research.

John Mackey, co-CEO of Whole Foods Market, is a member of The Motley Fool's board of directors. Michael Tsangaris has no position in any stocks mentioned. The Motley Fool recommends Costco Wholesale and Whole Foods Market. The Motley Fool owns shares of Costco Wholesale and Whole Foods Market. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.