Untersuchungen zur hygienischen und mikrobiologischen Qualität von marinierten Fleischzubereitungen zur Festlegung von Richtwerten bei der Kontrolle des Mindesthaltbarkeitsdatums (MHD) Tierärztliche Fakultät - Digitale Hochschulschriften der LMU - Teil 01/07
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Examinations concerning the microbiological and hygienic quality of marinated meat preparations in order to determine guidelines to control the best-before-date
In this study 52 marinades, 5 seasoning mixtures and 1 lemon seasoning were surveyed at the time of delivery and again following 4 weeks of refrigeration at + 6 °C ± 2°C. An analysis was also performed on self-made meat preparations consisting of pork respectively venison marinated in three different marinades. The marinated meat samples were produced and examined in duplicate to increase statistical accuracy. The examinations were carried out after 1 and 2 weeks of cold storage and after 6 weeks of deep freezing in order to determine the best-before-date of these self-service-products. The effect of an interruption in the cold chain was also examined as follows: 3 hours interruption for cold storage products and 5 hours for frozen products. This procedure was chosen to simulate the interruptions occuring during transport from dealer to customer or from customer to customer.
All samples were examined in the following three categories: sensory examination, microbiological survey, and pH value.
The sensory examination included “general characteristics”, “external qualities”, “consistency”, “appearance”, “odor”, “taste” and “haptic consistency”. Taste and haptic consistency were only determined for the marinades and seasoning mixtures, as the marinated meat could only be examined in raw condition and could therefore not be analysed concerning taste.
The microbiological survey included the examination of total viable count, B. cereus, Enterobacteriaceae, E. coli, C. perfringens, lactic acid bacteria, coagulase-positive staphylococci and salmonellae.
The pH-value was measured by means of a pH-meter if possible. In the case of oil-containing marinades the pH-value was determined using pH-indicator paper.
According to the sensory examinations, neither the marinades nor the seasoning mixtures had to be rejected after the initial examination nor after the 4 weeks storage. The high intensity of taste can be explained by the very spicy character of the concentrated marinades. The marinades are generally meant to be used as a taste enhancing component in meat preparations and are not intended for direct consumption.
The sensory examination of the marinated pork samples revealed a musty and odor compo-nent in 33 % of the samples after 1 week and in 100 % after 2 weeks of cold storage. According to sensory examinations 67 % of the samples were eventually classified as spoilt after 2 weeks. Only 33 % of the deep frozen samples were judged as musty and dull while none of those samples was spoilt after 6 weeks storage. Such sensory defects as a slimy and rope forming consistency were observed in 33 % of the samples after 2 and 6 weeks of storage, while 67 % of the frozen samples showed separation of fat within the marinades.
The sensory examination of the marinated venison samples revealed that 17 % had a musty and dull odor after 1 week, increasing to 50 % after 2 weeks of cold storage. In 33 % of the samples frozen for 6 weeks a musty and dull odor was observed. Putrid smell and spoilage could be detected in 33% of the samples after 1 week, in 67% after 2 weeks cold storage and in none of the samples after deep freezing. 33 % of the samples were slimy and rope forming after 1 as well as 2 weeks of cold storage. Separation of fat occurred only in the frozen samples (67 % of the samples). No significant differences could be observed between samples subjected to an interruption of the cold chain and samples held at constant temperature.
The microbiological survey of the marinades revealed no occurrence of pathogenic bacteria in critical amounts, with the exception of the detection of B. cereus and C. perfringens in small quantities. Both species of bacteria are to be considered innocuous, because the marinades are subjected to heat treatment together w
Examinations concerning the microbiological and hygienic quality of marinated meat preparations in order to determine guidelines to control the best-before-date
In this study 52 marinades, 5 seasoning mixtures and 1 lemon seasoning were surveyed at the time of delivery and again following 4 weeks of refrigeration at + 6 °C ± 2°C. An analysis was also performed on self-made meat preparations consisting of pork respectively venison marinated in three different marinades. The marinated meat samples were produced and examined in duplicate to increase statistical accuracy. The examinations were carried out after 1 and 2 weeks of cold storage and after 6 weeks of deep freezing in order to determine the best-before-date of these self-service-products. The effect of an interruption in the cold chain was also examined as follows: 3 hours interruption for cold storage products and 5 hours for frozen products. This procedure was chosen to simulate the interruptions occuring during transport from dealer to customer or from customer to customer.
All samples were examined in the following three categories: sensory examination, microbiological survey, and pH value.
The sensory examination included “general characteristics”, “external qualities”, “consistency”, “appearance”, “odor”, “taste” and “haptic consistency”. Taste and haptic consistency were only determined for the marinades and seasoning mixtures, as the marinated meat could only be examined in raw condition and could therefore not be analysed concerning taste.
The microbiological survey included the examination of total viable count, B. cereus, Enterobacteriaceae, E. coli, C. perfringens, lactic acid bacteria, coagulase-positive staphylococci and salmonellae.
The pH-value was measured by means of a pH-meter if possible. In the case of oil-containing marinades the pH-value was determined using pH-indicator paper.
According to the sensory examinations, neither the marinades nor the seasoning mixtures had to be rejected after the initial examination nor after the 4 weeks storage. The high intensity of taste can be explained by the very spicy character of the concentrated marinades. The marinades are generally meant to be used as a taste enhancing component in meat preparations and are not intended for direct consumption.
The sensory examination of the marinated pork samples revealed a musty and odor compo-nent in 33 % of the samples after 1 week and in 100 % after 2 weeks of cold storage. According to sensory examinations 67 % of the samples were eventually classified as spoilt after 2 weeks. Only 33 % of the deep frozen samples were judged as musty and dull while none of those samples was spoilt after 6 weeks storage. Such sensory defects as a slimy and rope forming consistency were observed in 33 % of the samples after 2 and 6 weeks of storage, while 67 % of the frozen samples showed separation of fat within the marinades.
The sensory examination of the marinated venison samples revealed that 17 % had a musty and dull odor after 1 week, increasing to 50 % after 2 weeks of cold storage. In 33 % of the samples frozen for 6 weeks a musty and dull odor was observed. Putrid smell and spoilage could be detected in 33% of the samples after 1 week, in 67% after 2 weeks cold storage and in none of the samples after deep freezing. 33 % of the samples were slimy and rope forming after 1 as well as 2 weeks of cold storage. Separation of fat occurred only in the frozen samples (67 % of the samples). No significant differences could be observed between samples subjected to an interruption of the cold chain and samples held at constant temperature.
The microbiological survey of the marinades revealed no occurrence of pathogenic bacteria in critical amounts, with the exception of the detection of B. cereus and C. perfringens in small quantities. Both species of bacteria are to be considered innocuous, because the marinades are subjected to heat treatment together w
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