- Routinely monitor town-based retail open mkts
- Microbial counts of almost all types of meats in Jaffna Town exceeding acceptable limits - High levels of faecal coliforms
- Contamination from unhygienic slaughtering practices
There is a need for the routine monitoring and verification of town-based retail open markets exposed directly to open environments to assess the efficiency of control measures and food safety recommendations. This is in the context of the microbial counts of almost all samples of chicken, beef, and mutton in open markets in the Jaffna Town exceeding the acceptable limits set by international and local standards with high levels of faecal coliforms with contamination likely resulting from unhygienic slaughtering practices, poor hygienic conditions, water, and open-air retailing under warm climatic conditions. This underscores the need for improved hygiene during slaughtering, processing, transportation, and retail storage to ensure the microbial safety of meat products including the poultry supply.
These recommendations and findings were made in an article on the "Evaluation of the chemical and microbiological quality of selected retail meats in Jaffna for health safety assessment" which was authored by G. Rajkumar, S C S Sabaragamuwa and A C Thavaranjit published in the Ruhuna Journal of Science's last June.
Meats are a nutrient-rich food that provides energy and essential nutrients, including proteins as well as micronutrients such as iron, zinc, and vitamin B12, which are vital for human growth, development, and health. However, high red meat consumption is linked to increased risks of cardiovascular disease, cancer, and metabolic disorders.
Global meat consumption has risen sharply over the past Century (20th) due to modern slaughtering and processing technologies, which have improved hygiene, commercialisation, and year-round. Poultry, in particular, has become a dominant protein source worldwide because of its rapid growth, efficient feed conversion, short fattening period, high reproductive capacity, and relatively low cost. In Sri Lanka, the poultry industry has transitioned from small-scale backyard systems to a highly commercialised sector over the past three decades, supported by advancements in breeding, feed formulation, hatchery management, disease control, and processing.
Meat quality, defined by physicochemical (e.g., the potential of hydrogen [pH], the water-holding capacity), sensory (e.g., tenderness, juiciness), and nutritional attributes, is a key determinant of consumer preference and product value. Among these, pH plays a central role, as a higher pH improves the water-holding capacity, tenderness, and shelf life, whereas a lower pH can negatively affect these qualities.
Most foodborne bacteria are unable to grow at water activity levels below approximately 0.90, although the exact threshold depends on the specific bacterial species and the prevailing temperature conditions. Water activity is a critical factor affecting the meat quality and shelf life. Most foodborne bacteria require a water activity above 0.90 to grow under typical storage conditions, and foods with a higher water content are more susceptible to microbial proliferation, which can reduce the shelf life. In meat, fat plays a key role in determining juiciness, flavour, and texture, and also provides essential fatty acids that humans cannot synthesise. Together, the water content and fat not only influence the sensory properties of meat but also affect its microbial stability and overall quality, underscoring their importance in meat processing and storage.
Meat is a high-quality protein source with high biological value, providing essential amino acids for human nutrition. However, its nutrient-rich composition, particularly high protein and water content, makes it highly susceptible to microbial contamination and spoilage. Contaminated raw meat is a major source of foodborne diseases, emphasising the need for proper handling, storage, and processing to ensure safety.
The primary sources of microbial contamination in meat include the animal’s hide and faeces. Additional external sources arise during handling and distribution, such as the floor and air of retail outlets, the slaughterhouse environment, and the vehicles used to transport meat from slaughterhouses to markets. Globally, the leading foodborne pathogens associated with meat are Campylobacter, Staphylococcus aureus, Escherichia coli, Salmonella, and Enterococci, which are responsible for millions of infections and fatalities each year.
Materials and Methodology
Rajkumar et al.'s study sought to assess the safety and quality of retail fresh meat sold in Jaffna, by evaluating the physicochemical properties (pH, the moisture content, the ash content [represents the inorganic mineral residue in meat after the combustion of organic matter and is typically expressed as a percentage, reflecting the total mineral concentration], the fat content, the protein content, the carbohydrate content, the water activity, and the total caloric content) and the microbiological quality (aerobic plate count, total coliforms and faecal coliform bacteria, Enterobacter, Escherichia coli, Staphylococcus aureus, Salmonella spp., and Shigella spp.) of fresh chicken, mutton, and beef samples collected from retail outlets.
Sample collection
Fresh chicken, beef, and mutton samples (15; five per meat type) were collected from retail outlets in the main market of Jaffna using a random sampling strategy to represent typical retail-level meat quality. Only skeletal muscle portions - chicken breast, beef muscle, and mutton muscle - were selected. Sampling was conducted once per week over four weeks during the morning hours.
Approximately 250 grams of each sample was aseptically excised, placed in sterile containers, and transported to the laboratory in insulated ice boxes at four plus/minus one degree Celsius. The samples were processed within 30–60 minutes and stored at four °C until analysis. Strict aseptic precautions were followed, including the use of sterile gloves, disinfected instruments, and sealed containers to prevent cross-contamination.
Results and Discussion
The physicochemical analysis of selected fresh meat types available in Jaffna
The pH
Meat pH is a key determinant of freshness, flavour, and overall quality. It influences palatability, microbial growth, and the water-holding capacity, alongside factors such as the salt content and temperature. Therefore, pH measurement is an important indicator of the meat quality, affecting the colour and texture.
Chicken exhibited the highest mean pH, greater than beef and mutton. pH is a result of postmortem metabolic changes that persist during the storage period, and it is dependent on the quantity of glycogen breakdown to lactic acid during anaerobic glycolysis. Elevated pH in chicken samples may indicate ante-mortem stress, which depletes glycogen reserves and limits postmortem lactic acid production.
Such stress could be physical in nature (e.g., temperature extremes, noise, confinement, crowding) or psychological (e.g., social group disruption, novel environments, noxious odours). These pH values align with reports for beef and ruminant meats, confirming typical postmortem acidification in non-stressed animals.
The moisture content
Moisture is regarded as one of the key physicochemical characteristics of meat, considering that it is fundamental to the meat's palatability. Fresh meat typically contains 70 per cent to 75% moisture, varying by species and cut. It affects the weight, density and viscosity of the meat and it allows microorganisms to grow. Chicken exhibited the highest mean moisture content, followed by mutton and beef.
The ash contents
The mean ash content was the highest in mutton and the lowest in beef. These values are consistent with the published data.
The fat contents
Fat, a key macronutrient alongside protein and carbohydrates, comprises triglycerides and contributes to the meat’s energy content, and sensory attributes. Variously sized fatty tissues (fat cells packed with lipids) can be found in meat. In meat, fat serves as an energy source, padding for the skin and around organs, particularly the heart and the kidney, and insulation against temperature loss.
Fat constitutes of an animal’s carcass, with variability depending on species, diet, and anatomical location. External body fat, which is higher in unsaturated fatty acids, is generally softer than the internal fat surrounding the organs. The skin is the primary source of fat in meat. The fat content also significantly influences meat quality attributes such as flavour, juiciness, and texture. The highest fat content values were observed in mutton and the lowest in chicken.
The protein contents
Meat is a protein-rich food with a high biological value, providing essential amino acids critical for human nutrition. Proteins are complex nitrogenous substances that exist naturally and have a very high molecular weight. They contain nitrogen, carbon, hydrogen, and oxygen. The elevated protein content of beef enhances its nutritional value by providing essential amino acids, such as leucine and lysine, which are critical for muscle repair and growth.
The carbohydrate contents
Carbohydrates in meat are very low because most glycogen is metabolised after slaughter. The mean carbohydrate content was the highest in beef, followed by chicken and mutton. These values are consistent with previous reports indicating that the carbohydrate content in meat is generally low, primarily due to residual glycogen in muscle tissues. Lower values in mutton are attributed to species-specific differences in muscle glycogen storage and post-mortem metabolism.
Water activity
Water is an essential component of all foods and strongly influences their quality and shelf life. Based on the moisture content, foods can be classified into perishable products and less perishable items. Water activity, defined as the ratio of a food’s vapour pressure to that of pure water, directly affects microbial growth and thereby governs the shelf life of meat and other perishable products.
Spoilage increases the concentration of solutes. However, different food varieties with the same water content have significantly different shelf life and spoilage characteristics.
The total caloric content
The total caloric content is the measurement of energy released from macronutrients. In meat, the total caloric content is in the form of fats and proteins.
The estimation of the microbiological quality of selected fresh meat types
All samples exhibited microbial loads above the baseline levels, with the aerobic plate count exceeding in most, indicating post-slaughter contamination consistent with raw meat handling.
The aerobic plate count
The aerobic plate count is used as an indicator of bacterial populations in a sample. It is also called the aerobic colony count, or standard plate count. It is a generic test for organisms that grow aerobically at mesophilic temperatures 25 degrees Celsius to 37 and psychrophiles generally lower than 10 degrees Celsius. The mesophilic counts were the highest in chicken, followed by beef and mutton. Psychrophilic bacteria were absent in chicken.
According to the Food Act, No. 26 of 1980, the aerobic plate count (mesophilic bacteria) in fresh meat should be less than a certain amount. This limit was exceeded in all meat samples, indicating high mesophilic contamination. The absence of psychrophilic bacteria in chicken samples may reflect the actual storage conditions (rapid cooling and short storage period) rather than limitations of the assay. In contrast, mutton exhibited higher psychrophilic counts than beef, suggesting longer storage or higher susceptibility to cold-tolerant microbes.
The higher mesophilic counts in chicken could be associated with the elevated moisture content and the pH. Slightly higher moisture and pH values were shown in chicken samples compared to beef and mutton. Given that poultry is dominating the Sri Lankan meat market, these elevated mesophilic loads highlight potential food safety risks, including spoilage and the presence of opportunistic pathogens.
The enumeration of the total coliform count
Coliform bacteria are often referred to as indicator organisms for faecal contamination and potential enteric pathogens in food. Specific types of coliform bacteria may be tested especially after a total coliform bacterium is present. These subgroups of coliform bacteria include faecal coliform and E. coli.
The mean total coliform count was slightly higher in chicken, followed by mutton and beef.
There were no recommendations on the total coliform count in the said Act. All raw meat samples had total coliform counts which much exceeded the acceptable limit.
A high coliform count indicates poor sanitary quality and may be accountable for economic losses as well as the presence of enteric pathogens that pose public health risks. The high total coliform count highlights the need for hygiene improvements in Jaffna’s poultry supply.
The enumeration of faecal coliform
A faecal coliform test was created because total coliform counts are insufficient to distinguish between faecal and non-faecal contamination. Faecal coliforms are thought to be more closely linked to faecal contamination in warm-blooded animals than other members of the coliform family.
Faecal coliforms were detected in all the samples. There are no specific limits for faecal coliforms in the said Act. All samples exceeded the acceptable level.
The enumeration of Enterobacter and E. coli
There are about 20 genera in the family Enterobacteriaceae, which include E. coli and the group of coliform bacteria. Numerous Enterobacteriaceae are found in the intestines of humans and other animals, some occur in water or soil whereas others are parasites on animals and plants.
Enterobacter counts were the highest in the mutton samples compared to chicken and beef. E. coli counts varied among the meat samples.
According to the said Act, the E. coli count in fresh meat should be less than a certain amount. Each and every sample exceeded the acceptable level in the E. coli count. So, it revealed that the butcher shops in the Jaffna Town are highly contaminated with faecal coliform, E. coli. Faecal contaminations occur by water and the butcher shops are mostly in open areas. This contamination occurred when handling, during transportation, and in storage - maybe they are contaminated with animal faeces.
This result showed that sufficient hygiene measures are not in place at the butcher shops in the Jaffna Town area, which leads to a high level of bacterial contamination in all the meat samples. Nonetheless, the presence of E. coli is concerning, as some strains, such as E. coli O157:H7, have been linked to the synthesis of Shiga toxins and have been linked to foodborne illness in people.
The enumeration of Staphylococcus aureus
Many pathogens have been responsible for food safety in recent years. Staphylococcus aureus is a prominent foodborne pathogen found in fresh and ready-to-eat foods that causes a variety of diseases. At room temperature, this bacterium multiplies rapidly and produces toxins that cause sickness. Naturally, S. aureus is found all over the world, but, the most common infection source for S. aureus is food.
The Staphylococcus aureus counts were the lowest in chicken, whereas beef samples had the highest counts, and then in mutton. According to the said Act, Staphylococcus aureus counts should be less than a certain amount. All three meat samples exceeded the acceptable limit.
The enumeration of Salmonella sp. and Shigella sp.
Salmonella sp. and Shigella sp. were not detected in any of the meat samples analysed. Salmonella has been identified as one of the most major pathogenic genera implicated in foodborne bacterial outbreaks and disorders. Salmonella infections are found all throughout the world and are a major public health issue in many countries. Salmonella causes an estimated 1.4 million episodes of foodborne disease and more than 500 deaths each year, according to reports. Salmonella is a growing public health concern because it is one of the most commonly implicated pathogenic microorganisms of bacterial food poisoning, especially in poultry meat. Infection occurs when raw poultry carcasses and products are handled, as well as when undercooked poultry meat is consumed.