Meat-free burger patties, nuggets and sausages are often marketed to consumers as being a healthy alternative to meat, but is plant-based really better for you?

While eating vegetarian and swapping out animal products for legumes or grains is not new, concern about climate change has led to a boom in non-meat alternatives.

But analysis from researchers at the University of Sydney and the University of Massachusetts has found plant-based foods often have high levels of additives, salt, genetically modified ingredients and allergens.

Researchers raised concerns that the protein quality in meat-free products could change, and products could be mislabelled with false claims, for example, that a product is healthier than meat.

Multiple plant proteins are known allergens, including soy, wheat, pea and lupin proteins which can cause issues for some, the analysis, published in Food Safety on Tuesday said.

Researchers also raised concerns over contamination, which plant-based foods were not generally linked with.

"(Plant-based meats) can become contaminated with pathogens via contact with contaminated sources of animal manure, water, or other foods," the analysis reads.

"Adopting a plant-based diet is among one of the most powerful things a person can do for the climate," the analysis' lead researcher Dr Diana Bogueva, from the School of Chemical and Biomolecular Engineering said.

But she stressed plant-based food manufacturers were part of a large and growing industry, and needed to ensure their food was nutritious and did not contain undeclared allergens, so their products were safe for consumption, as well as good for the environment.

"It has been estimated that if the highest-income nations adopted a more plant-centric diet, it could cut greenhouse emissions by around 61 percent - potentially freeing up land currently used for livestock for carbon sequestration, and saving huge swathes of forest at risk of land clearing," she added.

Many manufacturers in the industry are currently working on improving the healthiness and safety of their products, Dr Julian McClements from the University of Massachusetts said.