Carnimonas nigrificans and other microorganisms causing brown or black spots in fresh or cured meat products (hams, loins, pepperoni, sausage, ...) - Culture; Molecular diagnosis (PCR)
Information 10/15/30.
The appearance of spots or dots, brown or black, in fresh or cured meat products is a result of the growth of microorganisms. Stains or spots, brown or black, in cured meat products (ham, loin, sausage, chorizo, ...) are located superficially, mainly in oily areas without affecting the muscle tissue and connective tissue, and without alter its smell or texture. The presence of these stains is an important from the point of view of consumer acceptance for factor. Several species of fungi have been considered responsible for the appearance of these black spots in meat products stored at low temperature (-1): Cladosporium cladosporoides, Cladosporium herbarum, Cladosporium oxysporum, Penicillium hirsutum and Aureobasidium pullulans. Also, several species of yeast, Yarrowia lipolytica as (Saccharomyces lipolytica before) and Candida zeylanoides, among others, have also been implicated.
Bacteria, Carnimonas nigrificans, was found responsible for the development of these spots, or black spots in cured meat products. Its development is favored by the addition of dextrose, maltose or dextrin, while inhibited by the addition of sodium nitrite or potassium bisulphite. Also we found other bacteria (Pseudomonas fluorescens) that can acquire black coloration under certain culture conditions in the laboratory, and that are likely to also be involved.
Curing some meat products, such as hams, it involves a process of maturation of 18 to 24 months with salt and cold to prevent the growth of microorganisms until the product is stabilized by reducing its water content. Finally, a ham, for example, reduce its pH to 5.6 to 6.5 and a value of 0.80 or less water. Under these conditions the growth of microorganisms is not favored. However, when the ripening process does not develop properly, or pH levels or adequate water are achieved, microorganisms which cause product degradation can develop, alter its appearance or organoleptic characteristics, with the consequent rejection consumer and economic loss for the processing industry.
Among bacteria, the main cause has been found Carnimonas nigrificans, but they have also found other bacteria such as Pseudomonas fluorescens. To prevent its development, it is important to control the conditions of curing and preservation after the ripening process, maintaining at 5 ° C, until essentially its content in surface water is reduced to less than 0.92, and its salt content is 2 %, as even with salt concentrations of 2 and 5% to 5 or 25, may develop black spots producing bacteria if the water content is 0.94 to 0.97.
However, yeasts and molds can survive and develop in refrigerated meat in air and in vacuum packed meat, can also develop when the transmission rate of oxygen through the wrapper is high. Yeasts and molds require oxygen to grow, and can do so from temperatures below 0 ° C to 40 ° C, depending on the species, so that tolerate and develop refrigeration temperature. Most tolerate little activity (presence) of water and prefer a slightly acidic environment with pH from 4.4 to 5.5. For these reasons, the measure used to prevent the development of bacteria in hams, does not prevent the development in other types of sausage, such as salami or sausage, and contamination of meat or casings used should be avoided with yeast or molds.
Tests in IVAMI:
- For bacteria and / or fungi (yeasts and molds).
- PCR for bacteria and / or fungi (yeasts and molds).
- Identification of bacteria and / or fungi (yeasts and molds) by sequencing.
Recommended sample:
- Meat product with black spots.
Preservation and shipment of sample:
- Refrigerated (preferred) for less than 2 days.
- Frozen: over 2 days.
Delivery term:
- Culture for isolation: 4 working days.
- Molecular targets for PCR: 48 to 96 hours.
Cost of the test:
Consult ivami@ivami.com
FAQs
The appearance of spots or dots, brown or black, in fresh or cured meat products is a result of the growth of microorganisms.
What bacteria is in cured meat? ›
Detailed Solution. The bacterial spoilage-causing organisms in processed and cured meats are lactic acid bacteria (such as Lactobacillus sake, Lactobacillus curvatus, Leuconostoc gelidium, Leuconostoc carnosum, Leuconostoc mesenteroides), Acinetobacter, Bacillus, Micrococcus, Serratia, and Staphylococcus.
What are the black spots on pork skin? ›
The mite causing these pustules and subsequent black spots is known as Demodex fulliculorum yar suis, a very large name for such a small mite, that may be seen only by the aid of a magnifying glass.
Can you eat salami with black spots? ›
As for the mold present on the salami, if it takes on a black color and penetrates inside the salami, it means that the curing of the salami has failed and the product inside the 'casing has deteriorated. Although yellow-colored mold is to be avoided, when it happens we are certainly talking about bad mold.
Is mold on cured meat bad? ›
Contrary to popular belief, "good" molds act as natural preservatives, keeping your cured meats for longer with their flavors intact. In the case of artisanal cured meats, chances are that a smattering of white mold is actually helping the food rather than hurting it.
Is cured meat safe to eat? ›
Unlike that chicken breast that you took out of the fridge a few days ago, cured meat is safe to eat as long as proper safety guidelines are followed. The main component that sets rancid and cured meats apart is moisture. A steak that sits out in the sun all day will grow harmful bacteria which can make you sick.
Is cured ham safe to eat? ›
Whether the meat is smoked or cooked, the brine and the high cooking temperatures work together to kill bacteria and create a ham that is cooked and safe to eat. In short, if you purchase a ham that is labeled as cured, smoked, or baked this, it is likely "pre-cooked" and safe to eat.
Does cured meat have parasites? ›
Results indicate a low prevalence of infective forms of the parasite in cured meat products. However, some level of risk remains because of the inability of current meat inspection procedures at slaughterhouse to detect the parasite, and the curing process not always being effective.
Is cured meat cancerous? ›
Processed meats are meats that have been preserved by smoking or salting, curing or adding chemical preservatives. They include deli meats, bacon and hot dogs. Eating processed meats increases your cancer risk. Unfortunately, when these processed meats are preserved, cancer-causing substances form.
What are the brown spots on pork? ›
Other situations with very low oxygen can create brown spots. That's why you will see brown under the stickers on packages or on the underside of the meat cuts. In some cases, bacteria can cause the meat to turn brown, but when this happens, the bacteria will also create a smell.
If the meat has taken on a pale gray, brown, or yellow hue, it's probably not safe to eat. It's also time to toss it if it's grown any mold.
What is pork melanosis? ›
A network of deposits of melanin can be seen in the subcutaneous tissue of the udder area in a pig carcass in the abattoir. Congenital macular melanosis consist in hyperpigmentation of various tissues and organs caused by accumulation of melanin, in this case in the mammary area.
What are the black dots on pepperoni? ›
Some molds cause spoilage by forming black, white, or blue-green spots on the surface of meat and meat products. Gill, Lowry, and Di Menna (1981) isolated Cladosporium cladosporioides, Cladosporium herbarum, Penicillium hirsutum, and Aureobasidium pullulans from blackspotted spoiled meat, whereas Lozano-Ojalvo et al.
What is the brown stuff on salami? ›
However, if left out for too long, bad bacteria will eventually grow. These usually look like black, green, grey, or brown fuzzy spots. Once you see these little guys, it's time to say goodbye to your salami.
What are the black spots on pancetta? ›
Black (or any other dark) dots are most likely mold, and it's not the good white mold some cured meats tend to develop, either! If you notice any dark spots on your pancetta, immediately dispose of the product. It's one of the most significant visual signifiers that the meat has gone bad and is unfit for consumption.
What does it mean when meat has black spots? ›
Black discolouration of pork and beef adipose tissue is a relatively rare but quite eye-catching phenomenon and an obvious sign of advanced spoilage of the affected meat surfaces.
What are the spots on prosciutto? ›
Scientifically, these white spots are called Tyrosine or Tyrosine Crystals. It's one of the amino acids that are part of the protein chain and is therefore present in the meat of the Iberian pig. Tyrosine crystals are formed during the maturation of the ham.
What does bad cured meat look like? ›
There are two types of bad molds on cured meats: green and black. Green mold found on cured meat is a sign that the storage room in which you keep it has either too much humidity or very poor air ventilation.
What are the black spots on serrano ham? ›
A: It is normal for a thin layer of mold to appear on hams, particularly in high-humidity conditions. This penicillin-like mold is completely harmless. Simply remove it with a clean, damp cloth, or with a cloth soaked in olive oil.
