To continuously earn the trust that consumers place in the dairy industry, it is imperative that milk is rigorously screened at distinct points along the supply chain to identify any contaminants including antibiotics, pesticides, and toxins.
The responsibility for this dairy testing is shouldered by various different stakeholders, including farmers, processing plants, packaging facilities, food testing laboratories and regulatory authorities - with each having different safety testing requirements. The complexity of dairy supply chains, compounded by global and highly localized food regulations, can make defining these specific safety testing requirements a challenging job.
“Tinder” for dairy testing
Matching the appropriate testing instrumentation and methodology with the appropriate point in the supply chain is crucial in the effort to prevent dairy contamination, as well as to drive dairy-based businesses and food testing agencies forward to work easily and efficiently.
For example, rapid qualitative test strips can be used by non-scientists, on-the-farm or in-a-truck, to uncover antibiotic contamination within minutes.
In contrast, the intricate analysis of heavy metals relies on ICP-MS analysis, which must be undertaken in a laboratory setting. For analyses such as the detection of trace elements, mass spectrometry instruments can provide the high sensitivity and accuracy needed.
Potential milk contaminants are varied and include anything from unsafe levels of heavy metals to the presence of pathogenic bacteria.
- Contamination with certain strains of E. Coli, Salmonella or Listeria can cause debilitating illness, particularly in vulnerable populations such as young children and pregnant women.
- Pesticides or fungal aflatoxins that find their way into milk products may also cause serious illness, and are known to be carcinogenic; populations exposed to aflatoxins are particularly susceptible to liver cancer.
- Antibiotics are also common residues identified in milk as they are routinely used to treat animal illnesses. In a world where antimicrobial resistance is rising, it is imperative that populations are not consistently ingesting small amounts of these drugs and significant efforts are in force to monitor and control the levels of antibiotics that we are exposed to.
Aside from accidental contamination, milk and other dairy products may also be subject to economically motivated adulteration (EMA): the intentional adulteration of food in order to generate higher profits. A common method of milk adulteration is to simply water it down.
Although this may seem to pose little threat to consumer health, there is always the risk that the water used may not be fit for human consumption, and any addition of trace elements or particulates to consumer products may pose a risk.
The very worst-case scenario
Other EMA cases involving milk stem from the fact that milk is valued based on its protein content. This is often calculated based on the overall nitrogen content of the product, leaving scope for fraudsters to increase the apparent protein content of milk with nitrogen-rich adulterants such as melamine. This particular form of adulteration was brought to the world’s attention in 2008, when melamine added to milk products in China caused illness in over 300,000 babies and led to several deaths.
Developing a unified cow, commingle, and cross-border strategy
There are many factors to consider when a business within the dairy supply chain is devising a suitable testing strategy. One of the most important factors is understanding the local and international regulations governing the levels at which different potential contaminants must be quantified. These regulations are not harmonized and can vary widely between jurisdictions.
For instance, Russia generally follows the EU’s MRLs for antibiotics in food, however for the tetracycline drug family, the Russian food standards agency have instated much stricter regulations.
Clearly, dairy producers must be sure that they have the correct methods in place to fulfill the regulations where their product is sold, not just where it is produced.
Another factor is the inherent complexity of the dairy supply chain and the ever-present threat that an entire batch can be compromised from the potential contamination of a single cow. Milk from multiple farms is mixed together and sent to a processing plant that may be in another state or even another country. Here it will be homogenized, pasteurized and packaged before being shipped in chilled delivery trucks to retailers.
In order to mitigate and uncover a potential contamination source, processing companies hold back samples of milk from each individual farm. If testing on the whole batch indicates unsafe levels of antibiotics, these samples can be readily tested and the antibiotics can be traced back to the source of the contamination. The dairy supply chain is also connected to the broader food supply chain in that all the food ingested by dairy cows affects the composition of the milk produced.
Businesses at the front end of the supply chain must have rigorous screening methods in place. Their testing requirements can be fulfilled with the front line of analytical tools: testing strips, spectroscopy and immunoassays. Meanwhile, at the backend of the supply chain within third party testing facilities and regulatory authorities, there is a need for more advanced analytical equipment.
Public safety, regulatory compliance, cost efficiency and time to report are considerations for anyone conducting food safety tests. In addition to those overarching requirements, specific needs arise from the reason the test is being conducted. Whether the purpose is to return an animal to herd, accept a tanker into a processing plant, verify and pay suppliers or monitor public health, different stakeholders will have very different needs.
In many cases where there is risk of fresh milk spoiling, the time to result is paramount and rapid testing options should be considered.
For legal investigations and confirmation of screening results that indicate contamination, accuracy and sensitivity is more important than time, and analytical instrumentation such as LC-MSMS will be required.
The types of samples (e.g. dried milk, fresh milk, cheese) and the desired throughput is also an important consideration when deciding which equipment is appropriate. Complex matrices like cheese may require sample extraction and preparation to deliver accurate results. Food testing laboratories may consider automated instrumentation to help reduce manual sample processing for efficiency improvements.
Finally, many people who carry out testing in the supply chain are not scientists, and the user’s skill level and ability to understand and communicate results is important. When returning an animal to herd, a simple yes/no output is the most practical, allowing decisions to be made quickly. By contrast, in a government laboratory, more detailed analysis by scientists is likely to be required.
Meeting the needs of a globalized industry
As globalization continues apace, dairy manufacturers must comply with the montage of safety regulations set by authoritative bodies in an ever-connecting number of countries. These regulations are also escalating in their stringency, seemingly updated each week.
Recent high-profile food scandals have driven an increasing demand for stricter transparency about the contents of the food that consumers purchase. Furthermore, in a competitive industry, there is always demand for faster, more efficient, simpler technology that can enable real-time results for real-time decision-making.
By adopting the right technology and methods, companies in the dairy industry can secure their brand integrity, ensure product safety and deliver products that live up to consumer expectations.