Jana Partners has taken an 8.3% stake in Whole Foods leading to a share spike for the organic grocers and prompting calls that the supermarket should consider putting itself up for sale.

The US media is reporting how the activist investor now wants talks with the organic grocers on senior management, governance, real estate holdings, logistics, procurements and more, after taking the stake in the US supermarkets chain.

In recent years Whole Foods - which has more than 430 stores across the US, Canada and the UK -  sales have suffered as more competitors move into the organic and natural grocery space and availability of food products without artificial colorings, preservatives, flavors, sweeteners and so on have is much greater than previous years.

These factors have also prompted Whole Foods to review some of its prices, which have historically been considered very high, and hold more promotional activity such as offering customers a loyalty program.

However, as the natural food sector is being shaken up by more retailers and grocers coming in, the once uniqueness of Whole Foods - it was America’s first certified organic grocer - has dwindled, with many shoppers seeking out organic and natural labels from other cheaper grocers.

Following the announcement of Jana Partners taking the stake yesterday (Apr 10), shares in Whole Foods increased by almost 10%, closing at US$34.17 on Monday.