But that may soon become a thing of the past.
University of Otago researchers are working to harness the power of peptides in a spray to help the red meat industry combat bacterial contamination and spoilage.
The red meat industry in New Zealand contributes $10.8 billion annually to the economy, accounting for about 15% of the country’s total export earnings.
However, up to 1% of exported products are returned or rejected due to bacterial spoilage or contamination, resulting in financial losses amounting to tens of millions of dollars each year.
Otago microbiologist Associate Prof Daniel Pletzer said bacteria formed "biofilms" on meat — a dense matrix of microbial cells that bacterial communities created — to seal themselves off from threats such as heat, cold or water.
Once they had securely encased themselves upon a piece of unwrapped steak in the refrigerator, they were free to begin breaking it down and harvesting its nutrients, leading to classic signs of spoilage.
Because biofilms were stubbornly effective at blocking traditional cleaners and antibiotics, scientists had engineered solutions like anti-biofilm coatings for surfaces, Assoc Prof Pletzer said.
But he and his fellow biomedical sciences researchers were pursuing a different approach, using peptides — tiny molecules that serve as the building blocks of life.
They are short chains of amino acids, found naturally in foods and the body, and they are crucial for many bodily functions, like cell signalling, immune response, tissue repair, metabolic control and hormone regulation.
"As soon as we encounter a virus, parasite or bacteria, the first thing our bodies do is produce functional peptides to fight them off."
After discovering a wealth of insights about certain peptides, Assoc Prof Pletzer and fellow microbiologist Dr Sam Wardell pondered how their discovery might translate into a practical new tool.
The country’s primary sector stood out as an obvious area that could benefit, and they started working with major red meat co-operative, Alliance Group NZ.
The duo’s proposed solution was a spray, specially designed to attack biofilm-building bacteria, that could be applied to meat within processing plants.
But first, they need to find the right peptides for the job.
Their search has already begun, and their project recently won a $1 million Smart Ideas grant from the Ministry of Business, Innovation and Employment to explore host defence peptides (HDPs).
Using artificial intelligence and computational algorithms, the team has already mined the genetic data of cattle and sheep to find the HDPs with the best chance of combating spoilage and pathogenic bacteria.
They have narrowed their search from thousands of possibilities to about 400 candidates, which are now being synthesised for testing.
Assoc Prof Pletzer said the team was screening the candidates against common spoilage-causing bacteria like E. coli and Listeria, as well as "good bacteria" like Lactobacillus, which helped maintain the balance of the human microbiome.
The aim was to find a peptide, or perhaps a combination of them, that could target biofilm-forming bacteria without harming the beneficial bugs.
If successful, it could have applications far beyond meat production, like treating farm equipment to prevent diseases like mastitis, or medical devices to reduce contamination.
More broadly, he believed it could aid the growing global movement to cut back on the use of chemical cleaners and broad-spectrum antibiotics, which had contributed to the rise of antibiotic-resistant "superbugs" like MRSA.
