Two-pronged approach to stop wastage in the milk supply chain
Milk is said to be one of the top five wasted ingredients in Australia, with litres of spoiled milk going down the drain every day. Australian dairy is very mindful of its stewardship role and the need to reduce waste from farm to manufacturing and beyond, so this mathematical modelling research from US scientists, including one now at the Washington University in St. Louis, may be of interest.
The scientists integrated their knowledge across milk production and processing, microbiology and the supply chain to try to find a solution to the age-old problem of spoiled milk.
Two main strategies were found for the beginning of the milk supply chain — on the farm and in the processing plant — to prevent psychrotolerant (cold-growing,) spore-forming bacteria from contaminating and prematurely spoiling milk:
- Premium payments such as bonuses (or penalties) based on lower (or higher) spoiling bacteria counts in raw milk.
- Investing in spore-reduction technologies at the processing level.
Their study, concluding that enacting both strategies could improve some milk shelf life anywhere between a half-day to 13 days, was published in July in the journal Frontiers in Sustainable Food Systems.
The study targeted the problem of premature spoilage of milk caused by bacteria — Bacillus sp. and Paenibacillus sp. — which enter raw milk on farms and whose hardy spores can survive pasteurisation.
Supply chain incentives:
Farmers should be encouraged to implement fixes and improve processes from the get-go — starting with milk from the cow’s udders — if they are rewarded for consistent high-quality milk in terms of spore-forming spoilage bacteria contamination and penalised for low-quality milk.
Contracts similar to this bonus/penalty guideline already exist in US livestock commodities such as eggs and chicken, the authors noted. In this paper, the researchers propose a new, flexible bonus/penalty system based solely on raw milk’s initial spore counts at production.
Milk-processing companies know that technologies such as microfiltration and bactofugation are costly to acquire, install and operate. But this research illustrated how using both of those approaches, including a third, double-bactofugation method, were the most effective ways long-term to eliminate spore-forming bacteria from milk.
Their models predicted, by using such processing-level interventions and investments, shelf lives for milk would increase across the board. That improved shelf life — defined as the first day when 5% of milk packages carry a specific bacterial count — ranged from 20–26 days (for small processing plants) to 28–31 days (medium) to an average of 34 days (large).
In short, the research showed that medium and large processors could enact interventions and improve their milk’s shelf life up to 13 and 12 days, respectively.
According to Forough Enayaty Ahangar, a newly arrived lecturer in supply chain optimisation at the Olin Business School: “The results of our optimisation models demonstrate that optimal combination of interventions is highly dependent on characteristics of each individual dairy processor. These characteristics include the volume of processed milk and the quality of supplied raw milk. Therefore, our optimisation models provide novel decision tools from which individual processors can benefit and determine the best strategy for their facility.”
The ultimate goal of the research is to support the development of a sustainable milk production supply chain with the help of digital tools development, where milk waste is reduced.
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